Coal and Coke.pdf

PART X
IRONMAKING COURSE
March 12th, Belo Horizonte, Brazil
INTRODUCTION
Coal and Coke

History
The man uses multiple energy sources to maintain and improve his life.
Coal was known in China many centuries before Christ.
The Romans during the invasion of Wales knew the " flammable ground " that
was removed from the mountains.
In 589 "flammable ground" was offered to the Emperor of Japan
Coal mining documents in the thirteenth century.
After 1700 the discovery that coal and coke could be used in the manufacture of
iron (Abraham Darby 1709).
Coal was the motor of the industrial revolution in England (1770).
1800: 10 million tons of coal in England.
1850: 56 million tons of coal in England.
1900: 229 million tonnes in England and 270 million tonnes in the USA.
Coal was the main element in the development of organic chemistry, and until
after the Second World War, the source of many chemical substances.

The Coal Future
The dispersed and large occurrence of coal makes it the main source of energy
for a variety of uses.
The world coal reserves are abundant compared to oil and natural gas, it is
widely dispersed across all continents and are estimated in around one trillion
tons.
The expected duration of the coal is over 190 years, compared with about 41
years for oil and 67 years for gas.
Oil (18,2%)
Natural Gas (18,1%)
Coal (63,7%)

Coal Sources
Total: 919 billion tonnes
Measured reserves (end of 2005 in billion tonnes), with the
participation of anthracite and bituminous coal in parenthesis.

Coal Production and Comsumption.

World Primary Energy Demand (IEA - World Energy Outlook 2004)
¾Fossil fuels will be responsible for nearly 90% in energy demand growth
until 2030.
Oil
Natural Gas
Coal
Nuclear
Hidraulic
Others
0
1 000
2 000
3 000
4 000
5 000
6 000
7 000
2010 2020
M
t
1970 1980 1990 2000 2030

Coal Importance in Metallurgy
Source: Robson Jacinto Coelho et all (REM jan mar 2004)
Hot Metal Production Costs Stratification
Coal is a major factor in cost of steel.

Coal Future in Cokemaking Process
The steel will maintain its importance as the main material of the industry in the
XXI century. Its potential has not yet been exhausted.
The production of steel by the blast furnace / converter route will be dominant for
at least the next two or three decades.
Coke is the main raw material of blast furnace process. The ironmaking process
in blast furnace is not possible without the coke due the physical requirements
"coke is the leading provider of permeability in the process." With the blast
furnace existence, there will be coke and, consequently, the coking coal will be
used in its manufacture.
Coal is and will still be used for many years as a partial substitute of coke in its
chemical and thermal roles in blast furnace process (pulverized coal injection).

PART X
IRONMAKING COURSE
Coal Genesis
and Formation

Volatile matter
Fixed carbon
Inherent
Moisture
Superficial
Moisture
CHNSO
Macerals
Vitrinite
Exinite
Inertinite
Inorganic
Inclusions
Ash
Coal is a rock fuel containing more than 50% in weight and more than 70% in
volume of carbonaceous material including inherent moisture.
Genesis and Formation of Coal

Coal
Coal is a
is a generic
generic term
term for a
for a complex
complex accumulation
accumulation of
of different
different organic
organic
substances
substances.
.
Thus
Thus,
, the
the sine
sine qua
qua non
non condition
condition for
for the
the formation
formation of
of coal
coal is
is the
the existence
existence of
of
organic
organic matter
matter.
.

The Pangea
In the end of Carboniferous Period (180 to 200 million years) there was a single
giant continental mass, the Pangea.
Ziegler's theory: the continent Gondwana turned clockwise and collided with
Laurasian which emerged slowly causing the formation of mountains (such as the
Appalachians).

Conditions for the formation of coal
•Beyond the existence of organic matter:
•geological accident (sedimentary basin)
•favorable climate for plant development
•biological attack / action of oxygen
•geophysical process
•time
•pressure
•temperature

Sedimentary basin
The rock
The rock pieces
pieces resulting
resulting from
from erosion
erosion of
of the
the crust
crust by
by the
the action
action of
of nature
nature,
, gives
gives
the
the name
name of
of sediments
sediments.
.
For a
For a long
long time,
time, the
the sediments
sediments have
have accumulated
accumulated in
in layers
layers,
, giving
giving rise
rise to
to
sedimentary
sedimentary rocks
rocks. The
. The various
various layers
layers of
of these
these rocks
rocks form
form the
the sedimentary
sedimentary
basins
basins.
.
Sedimentary
Sedimentary basins
basins are
are formed
formed by
by layers
layers of
of porous
porous sand
sand,
, sandstone
sandstone or
or
limestone
limestone.
.

Lagoons – small vegetation
Genesis of Brazilian Coal

PEAT

Pressure
(3 to 5 km of sediments)
Heat
(150 a 200 ºC)
Coal
layer
TIME
TIME
PEAT

Cycles Repetition of Coal Formation
Organic matter accumulated in
a swamp near the coast of a
continent
Transgression of marine water
in the swamp makes the peat
covered with sand and clay.
The process is repeated,
resulting in alternating layers of
non-marine and marine
deposits.

Philosophical definition of coal
•The Sun is the source of light and life on Earth, "is a ball of incandescent gas,
whose nucleus happens energy generation through thermo-nuclear reactions."
Coal is the sun's radiant energy, accumulated by plants that were buried,
subjected to thousands of cycles of heat and pressure over millions of years within
the earth.
Mineral
Substances
CO2
NO3
-
H2O
Oxygen
Carbohydrates
Lipids
Protein
Photosynthesis
Radiant energy (light)
Chlorophyll

Types of Coal
Peat: It is not considered as belonging to the series of coal, since it is an
material in the initial transformation of organic matter and retains many
characteristics of plant origin. The vegetable matter can be recognized in
detail in the turf. The pores are large, there is cellulose and moisture content
is around 70%.
Stage of Lignite (soft and hard)
• Compression produced by the increase of sediments overlapping and whose
principal effect is to reduce the empty places of the material deposited and the
subsequent expulsion of water.
• The material gradually changes from brown to black.
• Gradual increase in hardness.
• Change of surface appearance (from matte to shiny).

Origin and Formation of Coal
Stage of Coals
Increase in fixed carbon content.
Decrease of oxygen and nitrogen content.
Decrease of volatile matter content.
Increase in calorific value, due the increase of carbon content.
The temperature rise reflects in the chemical composition of coal, and the
pressure increase, caused by the weight of overlapped sediments and
tectonic movements actuate in the the physical properties such as hardness,
strength, porosity and optical anisotropy.

Stage of Anthracites
Characterized, under the chemical point of view, for the reduction of volatile
matter, especially in the final stage, and for the decrease of the hydrogen
content, with the formation of CH4, removed in gaseous form.

Coking coal
Anthracite
Lignite
Peat Sub-
Bituminous
Bituminous Graphite
Carbonification
Rank
Cause: Temperature, time and pressure.

Synopsis
Coal is formed from plant remains that have been compacted, buried, chemically
altered and metamorphosed by heat and pressure over geologic time.
Coal Formation (I):
The formation of coal is based on three main factors:
Initiation, maintenance and repetition of environments that propitiate large-scale
accumulation of sediments and plant conservation
Conditions within the depositional environmente to promote biological
degradation and alteration of sediments in peat (peat formation).
Geochemical procesess that induce chemistry coalification of peat in higher rank
coal.

Synopsis
Coal Formation (II):
Burial of sediments, subsidence of peatlands;
Full cut of contact with the atmosphere;
Overlapping of sediment in peat: compaction and subsidence, and
Increase in pressure and temperature.

Synopsis (II)
Humic coals, originated from the remains of terrestrial plants that at least
transitorily exposed to the atmosphere and, consequently, went through a stage
of peat.
Sapropel coals: originated from plankton, algae and / or terrestrial vegetation, by
putrefaction in marine or lacustrine environment, shallow and anaerobic.
Oil: is an oily substance, flammable, less dense than water, with a characteristic
odor, color ranging from black to dark brown and is a combination of molecules of
carbon and hydrogen. Its origin is linked to the decomposition of the beings that
compose the plankton - organisms suspended in fresh and salt water such as
protozoans, coelenterates and others - caused by low oxygen and bacterial
action. These decomposed beings were during over millions of years,
accumulating at the floor of seas and lakes, being pressured by the movements
of Earth's crust and transformed into the oily substance that is oil.

Final Synopsis (I)
Live plants Organic matter
Biological and chemical
degradation of organic
matter to peat
Thermochemical
conversion
of peat to coal

Coal in the World
For sources around one trillion tons, the life of coal for the current production is
about 230 years.
5 % of coal for blast furnace.
10 % of soft coal.
85 % unsuitable for coking coal, part may be used as fuel injection in blast
furnace.
3,7
26,7
2,0
16,3
26,8
11,4
0,5
6,7
5,9

Coal in Brazil
Coal
Coal importation
importation
Sources: 32 bilions of tons
Productions: ~ 4 millions tons per
year
High ash content
High sulphur content
High alkali content
High cost of extraction
Low coal yield
Coal
occurrences

PART X
IRONMAKING COURSE
Coal Mining

Coal Mining
Ground
Drilling
Explosion
Coal
Coal Layer
Layer

Coal Mining
Work of coal extracting from its natural environment, processing and
transportation to the place that it will be used.
Disassembly of the coal layer (drilling and / or detonation with explosives),
charging, transporting and crushing to a suitable size for further processing.

Coal Mining
Stages of the coal industry
1. Exploratory
Geological Research
Geophysical Research
Drilling Research
2. Viability Studying
3. Exploration
Mining Development
Mining Operation
Coal processing
4. Transportation
5. Utilization

Coal Mining
Activities before coal mining
Deposit
•Geology
•Mineralogy
•Mining methods
•Mineral processing
•Economy
•Environment
Planning
•Mininh methods seletion
•installation needs
•Project and engineering
OPENING AND
DEVELOPMENT
Opening of the pit and
tunnels
Stripping
•Surfaces and undergrounds
constructions
Coal localization and
avaliation
•Local Geology
•Geophysics
•Geochemistry
•Drilling
•Sampling
Reserves evaluation
•Drilling (mash)
•Pit or tunnel drilling
•Evaluation
Mining

Coal Mining
The first stage for the implantation of a mining unit is the establishment of a
research program, drilling teams, using simultaneously several drilling machines,
take the probe evidency.
Probe evidence are samples of 50 mm in diameter for definition of reserves /
characterization of coal or 200 mm in diameter, in sufficient quantities for various
tests, including those of washability.
Tests can get information on coal quality on the geological layer characteristics,
providing a perfect project of the mine, of the preparation plant and the
subsequent use of coal.

Coal Mining
E
X
P
L
O
R
A
T
O
R
Y
Probe
evidency
•Probe or drilling
tower
•Drilling column
•Tubes
•First tube: drill

Coal Mining
Organic Matter
Inorganic
Moisture
Organic Matter
Inorganic
Moisture
Float-Sink
Test
Complete characterization
Mining
Beneficiation
Aplication
Complete characterization

Coal Mining
Washability curve
It is made by the determination of the properties (ash, volatile matter and sulfur)
of the fractions that sink to a certain density of the dense liquid and float into
another density a bit higher. It also determines the percentage by weight of each
of these fractions.
Os valores acumulados são calculados, tabelando-se os rendimentos, matéria
volátil, cinza e enxofre para os carvões flutuados em diversas densidades. O
carvão metalúrgico é considerado como o flutuado em meio denso a várias
densidades.
A planta de preparação é projetada para remover a porção não-combustível do
carvão a um custo operacional mínimo e um rendimento ótimo.

Coal Mining
Types of Coal Mining
Underground
Underground
Ground
Drilling
Explosion
Coal
Coal Layer
Layer
Open Pit

Coal Mining
Stages of coal mining
Mining
Í Disassembly
Í Charging
Í Transport
Í Costs control
Í Environment
Geology
Sampling
Research
Digging stability
Project and engineering
Suply services
Energy
Maintenance
Occupational health and
security
Ventilation
Water control
Land recovering
ROM

Coal Mining
Steps to coal mining:
Depth of coal layer.
Thickness of coal layer.
Quantity and type of sediments overlapped.
Quantity of water encountered.
Presence and quantity of gas in the layer.
Other geological conditions, roof stability, existence of igneous inclusions, dip
angle of the layer, existence of flaws.

Coal Mining
Underground Mining

Coal Mining
Underground mining

Coal Mining
Underground Mining
Chambers
Chambers and
and pillars
pillars

Coal Mining
Underground mining – Longwall

Coal Mining
Underground Mining – Longwall

Coal Mining
Coal Processing
Processing
•ROM conversion to
consumable
products
ROM
Comsumption products
Classification
Processing
Pesquisa
Digging stability
Project and engineering
Suply services
Energy
Maintenance
Occupational health and
security
Ventilation
Water control
Land recovery

Coal Mining
Coal processing
Run
Run-
-of
of-
-Mine
Mine
v
vVariety
Variety of
of sizes
sizes
v
vHigh
High content
content of
of
impurities
impurities
Process
Process
v
vCrushing
Crushing
v
vClassification
Classification
v
vWashing
Washing
v
vDrying
Drying
Washed
Washed coal
coal
v
vSmall range
Small range of
of sizes
sizes
v
vLow
Low content
content of
of impurities
impurities
ØThe processing method use the density to remove impurities.
ØMagnetite is added to water to create an ambient in which multiple density levels are
created.
ØDifferent qualities of coal are produced

Coal Mining
Coal beneficiation
Tailing bunker
Clean coal Clean coal Clean coal
Thermal Dryer
Clean coal filter
Dewatering screen
Centrifuging
Dewatering screen
Froth Flotation
Tailing
Cyclone
Tailing
Bathing with dense
fluid
Tailing
Fine coal Medium coal Thick coal
Run-of-Mine
Crusher
Tailing Thickner
Charging

Coal Mining
Coal beneficiation
Pre-scrubber
Run-of-Mine
55 to 60% of ash
1000 t
243 t
17 t
12 t 740 t
60 t 170 t
Scrubber
752 t
Fines (18% ash)
Metalurgical Coal
(18% ash)
Seam Coal
(30 to 40% ash)
Tailings
(70 to 75% of ash)

Coal Mining
Coal marketing
Consumption products
MARKETING
•Coal for
cokemaking
and oters uses.
Definition of coal types
Standards and specifications
Transport to the costumers
Materials science and technology
Properties and products uses.
Ways of sales.

Coal Preparation for The Coke Oven Plant

Coal Preparation System
Storage yards
Maritime Terminal
Railway transportation
Conveyors belt system
Dumper wagon
Coal sampler
Magnetic separator
Magnetic separator
Coal bunker
Scales system
Mechanical Mixer
Coal Blend Bunker
Blending sampler Coke oven battery
Coal sampling
Crushing system

Car Dumper
Í
ÍCar
Car dumper
dumper with
with water
water sprays
sprays
Í
ÍAutomatic
Automatic weighing
weighing and
and emptying
emptying

Storage in Yards of Steel Industry
ÍDead storage (to prevent transportation problems and keep a steady flow) and
alive storage (supplies directly the consumer or the means of transport): the coal
is removed from the dead and transferred to the alive.
ÍSilo between regular consumption of coke oven battery and irregular receiving
of ships.
ÍOpen storage (outdoor):is used for large capacity, due to its lower cost in
relation to the closed storage.

Storage in Yards of Steel Industry
Thick green belt around the yards.
Covered conveyor belts.
Stacking and removal of coal (distribution-reclaiming).
Individual Stacks by type of coal.
Increase the homogeneity of the coal.
Limiting the storage time to prevent more severe oxidation of coal.

Distribution by Stacker-Reclaimer

Distribution by Stacker-Reclaimer
•
•Maximum height of fall during stacking.
Maximum height of fall during stacking.
•
•Maximum height of stacks.
Maximum height of stacks.
•
• Stacks located appropriately in relation to the wind direction.
Stacks located appropriately in relation to the wind direction.
•
• Water spray systems on conveyor belts before stacking.
Water spray systems on conveyor belts before stacking.
•
• Automated system of spraying water in the stacks.
Automated system of spraying water in the stacks.
•
• Tailing ponds for contention of the material carried by the wate
Tailing ponds for contention of the material carried by the waters.
rs.

Coal Distribution System by Stacker-Reclaimer
The system consists of a feeder conveyor belt, a conveyor belt of reverse
cycle and a bucket wheel.
The coal is carried by the feed conveyor to an intermediate transfer point,
where it is transferred to a reverse conveyor belt, which takes the coal to
the point of storage.

Coal Distribution in Yards
ÍIt should prevent the occurrence of segregation that makes the particles
of larger diameter be located in the outer and bottom stack zones and the
smaller diameter in the inner and higher stack zones. This arrangement
facilitates the movement of air currents through the larger particles, which
carry oxygen to the border region with smaller particles, due it has higher
specific surface are susceptible to oxidation, may generate hot points. It can
lead to located deterioration of coal.

Stacking Methods
W
Windrow
indrow,
, chevron
chevron e
e cone
cone-
-shell
shell

Windrow Method – Parallel Stacks
It is (with the stacker) a series of parallel stacks along the tyard, covering the
entire area of the stack soil.
When the first series of steps is completed a second row of stacks is constructed
by filling the gaps in the first serie of stacks.
The process continues until the entire stack is built (it can be flat-topped or not).
The advantage of this type of stack is that it avoids the segregation (the
arrangement of thicker material for each step is restricted by the triangular
section)
The thick material is distributed consistently throughout the stack.
The method can be applied only if the scope of the stacker reaches the extremity
of the yard.

Chevron Method
Consists in crossing from one side to another throughout the length of the court
with the stacker arranged to feed the center of stack.
A small stack of triangular section is deposited along the length of the court in the
first step of the stacker.
In the second step in the opposite direction a second chevron of coal will be
placed on the top of the first.
As the number of steps increases the stack increases in height and thickness of
chevrons reduces progressively (the same amount of material trying to cover a
perimeter of increased cross section).
If there is thick coal the main disadvantage of these methods is that there will be
segregation and larger particles tend to be deposited in the lower and outside
parts of the stackl.
Depending on the method of reclaiming used this method may not give the results
of homogeneity required.

Fines Generation in Yards
The winds and the transfer operations are largely responsible for the
existence of clouds of fine coal in the atmospheric air from stored coal or in
storage.
The generation of dust, beyond dependency of the winds action depends
on the sum of the free fall that coal is submitted, also responsible for the
increased percentage of fines.
In coal transfer operations should be used methods for dust removal. The
cheapest solution is to spray water.
Minimizing the problem of dust generation: prevention, removal,
suppression, containment and fines dilution.
The physical stability of the coal stacks can be made by spraying of binders
(synthetic polymers) which form a film on the surface, preventing the
formation of dust.

Evaluation in Yards Emissions
Method for measuring emissions with wind tunnel (for stacks).
Method for measuring the exposure profile (transfer points).
Method of measurements of wind barriers (green belt).
Quantification of settable dust (point counting technique on body-of-
evidence produced from samples collected in different parts of the plant and
in locations close to it).

Dreinage Water in Yards
Drainage water from coal stacks may have three undesirable aspects
regarding the viewpoint of use:
–high acidity, resulting from oxidation of pyrite (neutralization is made
by adding lime or limestone);
–contain particulate matter in suspension by mechanical drag made
by percolation water (this material may have dimensions such that it
behaves as colloid, dispersing in the liquid mass with slow
sedimentation rate), and
–contain heavy metals (such as Fe, Pb, Zn, Cd and Hg) dissolved in
water, resulting from the leaching action of acidic water (these metals
can be precipitated at higher pH and removed with particulate material
in devices called classifiers or thickeners).

Unstacking: Reclaimer or Jib-Loader

Unstacking of Coal in Yards
With Reclaimer: the unstacking of coal is made by the bucket wheels which
transfer the coal to reverse conveyor belt (now goes in the opposite direction)
and will discharge it in the feed conveyor, which takes the coal for further
processing.

Types of Unstacking
Í
ÍBench
Bench cut
cut, module
, module cut
cut e
e harrow
harrow cut
cut.
.

Oxidation During Coal Storage
Coal is a pyrophoric substance spontaneous combustion.
WIND
•If the O2 penetrates the stack, it
oxidizes.
•Increase of temperature.
•If the heat generated is not well
removed, it eventually ignites.
+ O2 H2O CO2
+ + HEAT
C
H

Oxidation Consequences
Reducing of rheological properties
Decrease of the mechanical strength of coke
Control problems with charge density.
Variations in the coke production.
Overheated charges.
Carbon deposit
Ovens deterioration
Increase of coke reactivity.
Decrease of coking rate.
Fines generation and difficult of handling.
Spontaneous combustion.
Sponge effect when adding oil.

Monitoring Oxidation Level
Systematic monitoring of coal received quality (rheological properties)
Observation and petrographic analysis
Extraction method with probe.

Steps to Prevent Oxidation
Stacks compression
Monitoring and eliminating hot points
Minimize pressure of the winds

Coal Classification by Rank
¾Coal is a heterogeneous material consisting of a wide variety, sizes and
quantities of plant residues over geological periods of time were consolidated
between the rock strata and altered by the combined effects of geological and
biological actions in addition to pressure and heat to form the coal layers.
¾Coalification is the development of peat through the stages of lignite, sub-
bituminous coal, bituminous coal and anthracite. The coalification involves the
progressive loss of volatile matter, from peat to anthracite, and, consequently, the
relative concentration of carbon (carbonification).
Peat Sub-betuminous Betuminous Anthracite

The coalification suffered by coal has an important role in it physical and chemical
properties.
The coalification correspond to all the changes that contribute to the formation of
coal: a individual stage of this transformation is called rank. The most common
classification of coal is by rank!

Volatile matter
Fixed carbon
Inherent
Moisture
Superficial
Moisture
CHNSO
Macerals
Vitrinite
Exinite
Inertinite
Inorganic
Inclusions
Ash
Coal is a rock fuel containing more than 50% in weight and more than 70% in
volume of carbonaceous material including inherent moisture.

The volatile matter on dry basis is converted to dry mineral matter free basis
(dmmf), and this is used in combination with the calorific value (dmmf) and carbon
content(dmmf) on classification of coal according to ASTM Standard D388.
The volatile matter is measured according to ASTM D3175, an gram of coal is
weighed into a platinum crucible and heated to 950 ± 20 °C for seven minutes.
The loss in weight, except moisture, is the volatile matter content of the sample”.

ASTM D388 Classification

Rank categories based on volatile matter:
The categories indicates in ASTM D388 are widely used in different contexts of
use coal, generally considering the daf base (dry ash free) or db (dry basis),
causing loss of ranking accuracy. This is the case for the coal classification by
volatile matter on dry basis used in the Brazilian steel industry.
In case of use of the volatile matter is more plausible to use the limits specified in
ASTM D388 (data in parenthis are approximate values for daf basis):
Bituminous coking coals with less than 22% volatile matter dmmf are low volatile
rank (~ 23% daf).
Bituminous coking coals with less than 31% volatile matter dmmf (~ 32.5% in daf)
are of medium volatile rank.
Coals with more than 31% volatile matter dmmf are high volatile rank.

Coal Rank by Reflectance
The predominant maceral is vitrinite in coal and has higher reflectance than
exinite and lower than the inertinite in the coal associated with it.
The vitrinite reflectance is independent of the maceral composition and gradually
increases with coal rank. Therefore, the rank can be determined by a method that
uses reflected light microscopy (although more accurate, due the high prices it is
less used in the routine):
A sample of milled coal (850 microns) is placed in a thermoplastic or cold resin,
and polished. The maceral vitrinite maximum reflectance is measured (ASTM
D2798 standard) in oil at 546 nm on 100 grains and the average of these values
Romax is taken as rank of the coal sample.”

Rank categories based on reflectance

GENERAL CONSIDERATIONS
COAL
Organic matter
Mineral matter
Inherent moisture
Ash
Superficial
moisture
Volatile matter
Fixed carbon
CHNSO
Macerals
Vitrinite
Exinite
Inertinite
Inorganic inclusions
Moisture

Coal macerals
Coal is a heterogeneous material made up of a wide variety, amounts and sizes
of plant residues that over periods of geological time have been consolidated
between rock strata and altered by the combined effects of biologic and
geologic action, besides pressure and heat to form coal seams. Viewed under
reflected light microscope, coal can be seen to be composed of three main
constituents named macerals: vitrinite appears grey, exinite black, and
inertinite white.
VITRINITE
EXINITE
INERTINITE

Rank of coal
Wood
Wood
Fuel
Fuel Lignite
Lignite
Peat
Peat Anthracite
Anthracite
Bituminous
Bituminous Graphite
Graphite
44 - 52
44 - 52
Carbon
Carbon 55 -75
55 -75
50 - 68
50 - 68 90 - 96
90 - 96
74 - 96
74 - 96 100
100
43 - 42
43 - 42
Oxygen
Oxygen 26 - 19
26 - 19
35 - 28
35 - 28 3 - 0
3 - 0
20 - 3
20 - 3 0
0
5 - 6
5 - 6
Hydrogen
Hydrogen 6 - 9
6 - 9
7 - 5
7 - 5 3 - 1
3 - 1
5 - 1
5 - 1 0
0
Coalification is the development from peat through the stages of lignite, sub-
bituminous and bituminous coals to anthracite. Coalification involves a
progressive loss of volatile, from peat to anthracite, and, consequently, a
relative concentration of carbon (carbonification). It corresponds to all
transformations which contribute to the formation of coal: a particular stage of
this transformation is called rank. The rank is determined by the measurement
of various physical and chemical parameters (commonly by carbon, volatile
matter and mean reflectance).

Ranking of coal: volatile matter is not an accurate parameter for the evaluation
of rank of coal because it is influenced by the chemical features of macerals
and petrographic variation which can affect the results of volatile matter test:
there are differences of volatility between macerals and the amount of
macerals varies from coal to coal mainly when they are from different
sources. Coals can be ranked more properly by the reflectance.
Volatile matter of vitrinite (%, daf)
0 0.1 0.2 0.3 0.4 0.5
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.0
Inertinite
Vitrinite
Exinite
Volatile
matter
of
vitrinite,
exinite
and
inertinite
(%,
daf)
HV AUS
MV AUS
LV AUS
LV CAN
HV CAN
MV CAN
JAPAN
2 4 6 10
10
20
30
40
50
Grain size (mm)
Content
of
inerts
(%,
vol.)

PART X
IRONMAKING COURSE
Coal Receiving
Logistic

Coal Receiving Logistics
Coal Oceanic Transportation
Coal is transported from the country of origin by ship. Those ships vary in size
and capability and are classified as follows:
Panamax Ships: They are capable of carrying 65 to 70 thousand tons of coal.
Cape Size Ships: They are capable of carrying 135 to 150 thousand tons of coal.
Handy Size Ships: They are capable of carrying 25 thousand tons of coal.
The most commonly used in Brazil is the Panamax due to its capacity, depth of
draft, submerged part of the ship, and easy combination of loads. This type of
ship has six to seven holds with capacity of approximately 10 000 tons each one.

Ships discharging at the port of Praia Mole - TECAR

Inside the hold of a ship with mineral charge.

Preliminary procedure for ship charging
The supplier informs the customer when coal is available at the port of departure.
The client tells the owner, (ship contracting company), the date that wants to
charge the ship.
The owner hires the ship and put it available at the Departure Port, giving the
ETA (Estimated Time of Arrival) of charge.
After the ship be charged, the owner passes to the customer, the ship plane's
charge, with the distribution of holds, the total amount charged and the ETA at the
port of discharge.

Coal Purchase Flow
Steel Plant
Schedule
90 days
Ship designation
30 days 10 days
Laydays
Journey
15-30 days
Pacific=
30 days
Atlantic=
15 days
P. Mole
5 days
1 day
Railroad
4-8 days
Charging
4 days 8 days
5 days 5 days

Discharge at Praia Mole Port
The facilities consist of one Pier with 730 m of quay that allows the berthing of 2
ships with the possibility of simultaneous discharge. It has 04 discharger ships
operated by ' Grab's .
Coal is transported from the discharger silos to the coal yard by conveyor belts.
The VALE Coal Yard has a storage capacity of 1.000.000 million tons. They are
04 yards (A, B, C and D), containing 02 jib loaders and 2 stack reclaimer .
The jib loaders remove the coal from the yards, carrying through the conveyor
belts to the charging station wagon.

Wagon Charging at Praia Mole Port.

Wagon discharging at the Steel Plant.

Coal Sea Transportation
Shipping is divided into: international or long-distance and coastal shipping
and cabotage (along the coast)
Offers low freight, relatively long trip time and varied availability.
Ships with 25 to 175 thousand ton.
Bulk
Bulk carriers
carriers
Characterized by long main deck, where the only highlight is the hold, they
have lateral tanks that can be charged grain / bulk charge / ballast water and
the holds are bigs to charge of low density. Those used for coal and coke are
generally classified by size.

Coal Sea Transportation
Í
ÍPort
Port Facilities
Facilities
Deep-draft ports
Yards
Blending Coal facilities
Automatic Samplers
ÍPorts properly structured with pier, appropriate draft (depth of water) and
cranes to operate ships.

Coal Sources for Steelmaking.
Major Coal Producers
(Mt -1999/2000)
1.000
900
300
240
220
163
112
515
3450
China
USA
India
Australia
South Africa
Russia
Poland
Others
Total
World Coal Trade (Mt -1999/2000)
185
300
240
220
163
112
Exportation (Coking Coal + Steam Coal)
Australia
South Africa
Indonesia
USA
China
Canada
Importation (Coking coal)
65
18
12
11
8
6
Japan
South Korea
Brazil
India
England
Italy

Arrival
USA, Canada, Australia, China,
South Africa and others
Yards
Time of Journey to Praia Mole
ÍSouth Africa: 13 days
Í USA: 15 days
Í Poland: 18 days
Í Canada: 30 days
Í Australia: 30 days
ÍChina (coke and coal) : 40 days
ÍJapan (coke): 42 a 45 days

Projection of Consumption and Coal Receiving

Boarding Program (TBN trip, laydays of departure terminal, final departure,
laydays receiving terminal, final arrival, demurrage, despatch, beginning and
ending of consumption)

Consumption Projection by coal type

Storage Control by coal type (in number of days and tonnes)

Coal Purchase
Coal selection (procedure for the characterization of new coals and monitoring of
the homogeneity of the coals used in the company)
Application of Mathematical Model of Coal Blending Formulation.
Fixed contracts for the purchase of coals covering a portion of the total
consumption of steel industry coal??

Coal Purchase
Contracts for short, medium and long time (optimal duration of contract)??
Spot coal purchases
Programming of annual purchases (dynamic application of the model)
Integration of information between purchases-operation-technical units
Introduction of clauses of repayment and penalties in coal contracts : moisture,
ash, volatile matter, sulfur, maximum Gieseler fluidity etc..

Coal Purchase
Monitoring changes in price of coal in short, medium and long time.
Interaction Company-Suppliers
Capacity of ships, number of coals for charging.
Purchase of straigth coal, blend coal, blended coal or coal blend
Emergency solutions in cases of perturbation of supply (diversification of sources,
use of domestic coal, mining investment, maintenance of safety storage).

Factors Hierarchy that Influence in Coke Quality
Coal
Blending Coking
condition
Pretreatment Others
Impact
on
Coke
Quality
(%)
Granulometry
Moisture
Burden density

Japanese Method for Strength Predicting
Miyazu Okuyama Fuhuyama M O F
Principle: A coal has to be sufficiently fuse for the cokemaking, in order to the
reactive macerals can agglutinate properly to each other and also to the inert
macerals.
A partir do momento em que a plasticidade atinge o seu valor ideal para
provocar a aglutinação, qualquer excesso não concede mais nenhuma vantagem
para a resistência do coque e pode mesmo levar à formação de coque esponja
de baixa resistência.
From the moment that the plasticity reaches its ideal value to cause
agglutination, any excess does not give any benefits to the strength of coke and
can even lead to the formation of sponge coke with low resistance.

The ability of an individual coal to produce coke is characterized by rank (vitrinite
reflectance) and the maximum Gieseler fluidity (or by the proportion reactive /
inert).
It is not possible obtain coke from a coal that does not have the property of
passing to plastic stage. However, in the case of individual coal that pass through
plastic stage, the particles join to each other even though the maximum fluidity is
low, since all the particles are plastic at the same temperature.

Rank effect of individual coal

Effect of the proportion reactive / inert of individual coal: i) “high or low reactive
reduce the strength and ii) the optimum amount depends on the rank.“

The higher the rank the lower the effect of inert content (up to Ro = 1.20%,
practically only the rank influence on DI).
Coque fabricado de misturas de carvões: “índice médio de rank e habilidade
aglutinante”.
Coke made from blending of coals: “rank and rheological properties”.
Influence of the rank: the relationship between Ro of coal blending and DI is
similar to that obtained for individual coal.

Effect of maximum fluidity of the coal blending, by mixing coals of different
ranks the temperatures that these coals reach their maximum fluidity are different.
It results in inconsistent plastic transition of low rank coals (Ro = 0.8%) and high
rank (Ro = 1.80%) and a coal can get soft when the other is still solid, and the
other will get soft when the first is already solidified. “

Se esses carvões são misturados na proporção 1:1 (ou seja, Ro da mistura
igual a 1,30%, o que atende ao limite de Ro 1,20%) é difícil a obtenção de
ligações fortes entre as partículas e de coque de alta resistência.
If these coals are mixed in the proportion 1:1 ( Ro of Mix equal to 1.30%,
according to the limit of Ro 1.20%) is difficult to obtain strong connections
between the particles and high resistance coke.
The introduction of a third coal (for example, an American high volatile, high
fluidity) whose plastic range is able to cover the plastic ranges of the first two
coals provides strong links between the particles.

Separation of the effects of rank and the maximum fluidity of coal blends
Experiences in commercial coke oven battery, seven components of mixtures
with two levels of reflectance and six levels of maximum fluidity.

For both values of coal blending Ro , the DI15-30 decreased with the decrease of
maximum fluidity, with a small variation below 200 ddpm and little change over
this value!

¾ log ddpm versus CBI
¾ CBI versus DI15-150

The factors that rule the coke strength can be consolidated in two parameters:
rank and rheological properties.

The rank of the mixture should be: Ro 1.20%.
The predicted fluidity has an optimum range, and the lower limit is 200 ddpm.
However, as the industry battery has operational fluctuations, the desired value
should be something more than 200ddpm.
The blends of coals used in the cokemaking are included in the range controlled
by the rank when the fluidity is in the optimum range, Ro is the only factor
affecting the resistance.“

The coal effectiveness with Ro ≥ 1,3% depends mainly on Ro.
The effectiveness of coal with Ro 1.1% depends mainly on the maximum fluidity.
¾ A efetividade de carvão com 1,1 Ro 1,3 depende tanto de Ro quanto da
fluidez máxima.
The effectiveness of coal with 1.1 Ro 1.3 depends on the fluidity and on the
Ro.
The strength of the coke when affected by the rank and by the inert content is not
appropriate to avaliate the coal quality.
The MOF diagram has a window for blanding used in cokemaking process.
log mix = ∑ xi log Ci
Rmix = ∑ xi RCi

The MOF diagram illustrates how the rheological properties is related to rank.
The results of the combination reflectance versus Gieseler fluidity applied to coals
used in Brazilian stellmaking process show as in the original diagram MOF, coal
of low levels of inert are located in areas related to coal with different origin and
coal with high inert are located below the curves. The more distant of the curve is
the representative point of a single coal, the lower is its rheological properties, the
lower is the amount of plastic mass offered, the weaker inter-particle links and the
greater the difficulties of being used as a component of coal blends.

PART X
IRONMAKING COURSE
Crushing

Influence of Particle Size
1 - The coking power of a coal is dependent on its particle size. Thus, particle
size constant distribution of the coal mixture is essential in order to have a
constant and high resistance of coke.
2 - Rose Blocks of Coke:
- inert particles and mineral matter of excessive size are sources of cracks;
- reactive particles with excessive size (+ 3mm) create large pores with irregular
shapes;
- fine reactive particles (- 0.2 mm) did not allow the formation of pores.
3 - The particle size in combination with moisture, controls the charge density:
- The higher the charge density the bigger proximity between the particles
(more intimate contact between the macerals of coal which is the primary goal
of crushing);
- The finer the coal, for the same moisture content, the lower the charge
density, in other words the greater the distance between the particles.

Ash Versus Particle Size
Ash
(%)
Screen (mm)

Inert Versus Particle Size
Screen (%)
Inert
Content
(%
in
volume)

Coal Size for Cokemaking
• It is necessary to crush coal to a suitable level of crushing!
• Operational Limitation: the level of crushing should be obtained in order to not
exceed the maximum allowed - 100mesh (the goal would not increase above the
rate existing in the coal).
• Achieving this goal minimize the loss of load density and the coal loss during
crushing and during coking (with gains in terms of pollution and safety).

Coal Size as Received
Retained Accumulated (%)
Screen
(mm)
SC-Brazil
BV-CAN
AV-EUA
MV-AUS

Particle Size of Coke Charged in Coke Battery.
The coal is crushed between the small limits of size (7mesh to 100mesh). This is
a compromise between:
- Obtain high charge density in the oven;
- Maximize the expansion of swelling coal particles;
- Obtain a more solid structure of the coke product;
- Minimize the adverse effects of thick mineral matter;
- Reduce environmental pollution and the negative effects of fines (carbon
deposits and insoluble material in quinoline in tar).

Factors That Influence on the Particle Size
Coal is an aggregate of the non-consolidated particles.
Some coals tend to pulverize with greater ease, forming high percentage of fines,
while others have more particle size stability.
The formation of fines depends largely on the maceral composition of coal as well
the content and nature of mineral matter and the level of intergrowth between the
mineral matter and carbonaceous matter.
Plenty of vitrite and fusite leads to greater tendency of coal to the formation of
fines.
Plenty of durito and clarita leads to greater stability to the coal particle size.
The higher the clay content the greater the aggregation between the particles and
the lower the tendency to spray.

Factors That Influence on the Particle Size
The wear or abrasion produced on the equipment should also be considered. The
abrasion depends mainly on the type of mineral matter present and the size of the
mineral matter. Quartz is very abrasive.
A coal can provide excellent grindability but can cause excessive wear in the
spray equipment.

Screen Series
ASTM (USS) TYLER MESH DIN Opening (mm) (Opening pol)
4 pol - - 101,6 4,00
3 1/2 pol - - 88,9 3,50
2 ½ pol - - 63,5 2,50
2 pol - - 50,8 2,00
1 ¾ pol - - 44,4 1,75
1 ½ pol - - 38,1 1,50
1 ¼ - - 31,7 1,25
1 pol - - 25,4 1,00
¾ pol - - 19,1 0,75
5/8 pol - - 15,9 0,625
½ pol - - 12,7 0,500
3/8 pol - - 9,52 0,375
5/16 pol - - 7,93 0,312
¼ pol - - 6,35 0,250
3,5 3,5 - 5,66 0,223
4 4 - 4,76 0,187
5 5 - 4,00 0,157
6 6 - 3,36 0,132
7 7 - 2,83 0,111
8 8 - 2,38 0,0937
10 9 - 2,00 0,0787
12 10 - 1,68 0,0661
14 12 4 1,41 0,0555
16 14 5 1,19 0,0469
18 16 6 1,00 0,0394
20 20 - 0,84 0,0331
25 24 8 0,71 0,0280
30 28 10 0,59 0,0232
35 32 12 0,50 0,0197
40 35 14 0,42 0,0165
45 42 18 0,35 0,0138
50 48 20 0,297 0,0117
60 60 24 0,250 0,0098
70 65 30 0,210 0,0083
80 80 35 0,177 0,0070
100 100 40 0,149 0,0059
120 115 50 0,125 0,0049
140 150 60 0,105 0,0041
170 170 70 0,088 0,0035
200 200 80 0,074 0,0029
230 250 100 0,062 0,0024
270 270 110 0,053 0,0021
325 325 130 0,044 0,0017
400 400 150 0,037 0,0015

Basics of Mechanical Size Particle Reduction
A material is reduced by:
Impact: instant and sharp break resulting from a moving body crashing against
another (impact crusher).
Friction: reduction resulting from a body subject to frictional action between two
surfaces.
Stress: break resulting from the combination of friction and impact or impact and
compression.
Compression: reduction resulting from the pressure on a body between two
surfaces (jaw crusher).

Mechanical Reduction by Impact
The impact process applies its energy to each particle in direct proportion to its
mass, the work is done mainly on the larger particles!
Lower energy consumption per ton crushed (the material is not forced in a
restricted area).
Because of lack of friction the maintenance will be less.
The lack of friction results in a product with cubical shape.
It is possible to obtain higher levels of spraying without the generation of
inadequate amounts of particles - 100mesh.

Mechanical Reduction by Impact
Collision of particles against a surface that moves at high speed or causing them
to collide at high speed against a fixed surface or both types of collision.
The energy to break is derived from the change of mass moment of the particle
when it collides with the surface and / or from energy supplied by the surface in
movement.
Impact is a free type process since the particle is not at any time subjected to
compressive forces applied by the fixed or mobile surface!
The material is broken along cleavage lines more or less natural without
generating frictional heat.

What is the Most Suitable Equipment to Get The Crushing Level for
The Charge of Slot Oven Battery?
When the goal is to reduce a material to a narrow distribution of sizes - as in the
case of coal that the maximum size limitations and proportion of fines suggest the
range between 7mesh - 100mesh - the principle of particle size reduction by
impact is indicated and often preferred.

Coal Crushers
Feeding rate!
Rotor speed!
Interlaminar distance!

Considerations About Crushing
The control of particle size of coal in impact crusher is made by control of
distance between baffle plates and plates of impact, by the measuring of the % in
weight of particles - 3mm of crushed coal.
During crushing is difficult to continuously control the particle size of coal
because the granulometry analysis takes time and work, then only an initial
adjustment is made.
The introduction of an automatic analyzer would involve big costs and the trouble
of maintaining and controlling the accuracy of sampling / analysis will ever come
to light.

Considerations About Crushing
It remains the possibility of predicting the size analysis of crushed coal through
equations that link the characteristics of raw coal to crushed coal and consider
the conditions of operation in the crushing.
Characteristics of coal:% + 7mesh, HGI, coefficient of particle uniformity.
Crushing conditions: feed rate, rotor speed etc..

Performance of Crushers
The performance of the company crushers is generally considered inappropriate
for people who operate them!
One option used in some company is the screening and recycling if the
preparation wants, quality of coke and reducing fines!

Crushing Types
Simple Crushing : pass the coal once in one or more crushers in serie.
Methodical crushing : passing coal through a screen, crush the oversize, recycle
the oversize crushed through a screen and so successively until all the coal
passing through a screen.
Global crushing : when the coals are premixed and the mixture is crushed.
Differential crushing : pass the coal once (brutal) by a single crusher trting to
obtain the defined particle size for coal. For each type of coal is defined a target
size.

Particle Size Versus DI 15-150
Crushing Level (% 7 mesh)
DI
15-150

Selective Crushing
B
Coal
Heated Screen
(5-15 mm)
(5-10 mm)
(5-5 mm)
First Screen
(14 mm)
Hammer Crusher
Coal - 5 mm

Selective Crushing
Fractions of vitrinite and clarenite that have good rheological properties are
clearly powdery, they are put in a granulometry range considered ideal for the
coal in question (for example, 1.5 to 3mm).
The durenite lower in rheological properties, is placed in a lower granulometry
(eg, - 1.5 mm).
The fusenite is finely crushed to be incorporated in the plastic coal during the
coking process.

Selective Crushing
Total Dilatation Audibert-Arnu (%)
Total
of
Inerts
(%,
in
volume)

Crushing Conditions for Impact Crusher
Coal
Itmann - LV
Lynco - HV
Brazilian - HVSC
Speed (m/s)
18
47
52
+ 3 mm
12,11
15,05
16,41
- 0,5 mm
32,84
29,28
27,00
- 0,15 mm
10,71
10,14
10,14

Crushing Conditions for Impact Crusher
Rotor Speed (rpm)
Granulometric
Index

Proportioning and Mechanical Blending of Coal Blend
Formula of coal blends is defined based on the characteristics of the coals and on
the desired characteristics for coke.
Number of coal in the blend: 4 to 20.
Proportioning silos house filled with defined coal for the mix.
Quantities defined for each coal in the mixture are obtained from scales located
below the proportioning silos house.
These quantities are fed into conveyors belt (layers) that drive to the mechanical
mixing of spinning blades.
The mixture of coal highly mixed is sent to the “Coal Bunker situated in an
elevated position in relation to the battery of coke ovens.

Proportioning and Mechanical Blending of Coal Blend
Advantages
ÍUniformity of blending.
ÍNumber of coal in the blending.
ÍAllows use of low percentages of coal
ÍLow capital investment
ÍStorage of blending.
Advantages
ÍPossibility of fast changing of coal
blend.
ÍLower levels of storage.
Disadvantages
ÍDifficulties of adjustments after blend
stack consolidation.
ÍRequires bigger area.
ÍRequires more time before of coal use.
Disadvantages
ÍVariability increased.
ÍLimited number of coal in the blending.
ÍHigher minimum percentage of coal in
the blend of coals.
ÍHigh costs of capital.
BED (Coal Yard) Proportioning Silos

Coal Blending Formule (% in weight)
AV1USA
AV2 USA
MV1 AUS
MV1 CAN
MV1 CAN)
MV2 AUS
MV3 AUS
MV1 USA
BV 1USA
11
12
7
13
7
13
14
14
9
USA: 46%
AUS: 34%
CAN: 20%
AV: 23%
MV: 68%
BV: 9%
Moisture (%): 6 a 11%
Ash (%): 7,5 a 8,5
Volatile Matter (%): 26,0 a 27,0
Sulphur (%): 0,6 a 0,7
Gieseler Fluidity (ddpm): 300 a 700
Refletance (%): 1,10 a 1,20

Blending Efficiency
Efficiency (%) = 100 ( 1 - Wb
2 / Wu
2 )
Wu
2 = MVCi
xi
MVCi -
( )2
xi
Wb
2 = MVSi si
- MVSi
( )2
si
Ci : coal i
xi : % in weight (dry basis) fo the coal i in the blend.
MVCi : Coal Volatile Matter i (% in dry basis)
Si: i section of the conveyor belt
si : % in weight (dry basis) of the i sectioni
MVSi : volatile matter of the section (% in dry basis)
∑ ∑
∑ ∑

Coal Route
Mixers
Silo
Crushers
Scale
Coal Stack
Mixing Coal Deposit

General Comments
Draining (pool cleaning, bobby cat etc).
Contamination
Mistakes of transport guides
Losses by wind at coal yard
Surface hardener coal stacks (vegetable oil, water + vegetable oil etc.).
Stacking with controlled segregation
Stacks compactation of certain coals
Coal arrangement (special arrangements, separation by type, rotation versus
deterioration etc.).
Regulating the crushers
Blades conditions
Clean crusher
Scale Errors
Flows in silos and scales
Scales conditions
Efficiency of the mixers
Interruption of flow in silos of coal bunker
Filling in the coal bunker silos

PART X
IRONMAKING COURSE
Coal and Coke
Characterization

Methodology for Characterization of Coal – Coke Oven Plant
Chemical characterization:
Proximate analysis (moisture, ash and volatile matter).
Elemental analysis (C, H, O, N, S)
Analysis of the ash composition.
(Al2O3, SiO2, Fe2O3, TiO2,CaO ,MgO, MnO, K2O, Na2O, ZnO, P2O5, SO3)
Petrografic analysis
Rank determination
Maceral type
Rheological properties
Free Swelling Index (FSI)
Gieseler plastometer
Dilatometry Audibert-Arnu

Methodology for Characterization of Coal – Coke Oven Plant
Coking oven pilot
Determination of coking pressure
Cokemaking
Characterization of coke:
Structural strength
Coke Reactivity Index – CRI
Coke Strenght after Reaction with CO2 – CSR
Mechanical strength
Drum Index – DI 15-150
Micum – M40 e M10

Physical Characterization of Coking Coal
Sizing analysis (ASTM D4749)
It allows the separation in particle sizes of coal crushed.
It consists of the superposition of screens, ordered from top to bottom according
to their openings in screens vibrator.
Granulometric indices representing the retained (or passing) on a given mesh:%
7mesh,% 100 mesh.
Crushing Level (% 7 mesh)
DI
15-150

Grindability Index(ASTM D0409)
Grindability is the measure of the facility with which coal can be pulverized or
reduced granulometrically to suitable size for use as pulverized fuel.
Hardgrove Grindability Index (HGI)
The HGI indicates the grindability of coal compared with chosen standard coals.
A prepared sample coal receives a set amount of milling energy in the Hardgrove
machine, the reduction of particle size is measured by screening.
Pulverizer ring-ball
8 one inch balls in diameter
Sample: 50 g of coal between 0.59 and 1.19 mm
Treatment: 60 revolutions (20 ± 1 rpm)
Screening at 200 mesh for 25 min in rotap
W = 50 - retained on 200 mesh
HGI = 13 + 6.93 w

Main Control Parameters for the Mixtures Formulation
Ash (ASTM D3174)
Measure the loss in weight (%) after complete incineration (burning with air at 725
°C ± 25 ° C)of the sample with 1 g of dry coal (-60 mesh).
The mineral matter in coal originates from its ashes after incineration operation of
the sample.
•AshMixture = xi . AshCoal i
=
∑
i
n
1

Schematic Representation of Sample Incineration
Air (O2, N2)
Ash
Organic matter
Inorganic inclusion
+ GAS

Volatile Matter (ASTM D3175)
Measure the loss in weight (%) sample of 1 g of dry coal (-60 mesh) heated to
950 ± 20 ° C for 7 minutes.
The volatile matter corresponds to the pyrolysis products of organic substance of
coal.
The volatile matter is composed of hydrocarbons, carbon dioxide and inherent
moisture.
•MVMistura = xi . MV Carvão i
=
∑
i
n
1

Coal Sulphur
The sulfur is present in organic, pyrite and sulfate forms in coal.
It is appropriate to consider only the total sulfur (LECO).
The coking coals have sulfur content between 0.3% and 0.9%.
Coke contains sulfides (from the dissociation of pyrite) and sulfur connected to
carbon structure (from organic or pyritic sulfur).
a, b, c, d and e are coefficients of correlation.
•SMistura = xi . SCarvãoi
•SCoque = a * SMistura – b * MVMistura + c
•SCoque = d * SMistura + e
=
∑
i
n
1

Petrographic Analysis
Determination of rank, stage reached by coal during its geological history, (ASTM
D2798): by measuring the amount of light reflected by vitrinite maceral.
Maceral analysis (ASTM D2799): quantification of coal macerals (vitrinite, exinite
and inertinite) using the technique of point counting on highly polished sample.
Petrographic microscope
Petrographic microscope
Rank determination
Maceral analysis

Coal Ash Analysis
After incineration of organic matter in a sample are analyzed the contents of
oxides in the ash.
Conventional methods.
Atomic absorption.
X-Rays

Coal Reflectogram (Rank)
Distribution of vitrinite types in coal.
Vitrinite type Range Times % in vol.
V10 1,00 ~1,09 1 1
V11 1,10 ~1,19 23 23,0
V12 1,20 ~1,29 41 41,0
V13 1,30 ~1,39 24 24,0
Total 100 100,0
V14 1,40 ~1,49 6 6,0
0
10
20
30
40
50
Vitrinite type
Frequency
V10 V12 V14
Ro = 1,20 %
σ = 0,10

Coal Maceral Analysis
Maceral Group Maceral Numbers of points %V (without mineral matter) % in Volume
Vitrinite Colinite (telinite) 370 74,0 71,6
Sporinite 11 2,2 2,1
Exinite
(Lipdinite)
Cutinite 3 0,6 0,6
Resinite 0 0,0 0,0
Semifusinite 66 13,2 12,8
Sclerotinite 1 0,2 0,2
Inertinite Micrinite 39 7,8 7,5
Fusinite 10 2,0 1,9
Mineral Matter n.d. n.d. 3,3
Total 500 100,0 100,0
Ash (% in dry base) 5,82
VITRINITE
EXINITE
INERTINITE

Free Swelling Index – FSI (ASTM D0720)
It was originated in the observation of buttons obtained in the determination of
volatile matter.
Measure of the bonding properties of coal.
1g of coal heating from room temperature to 825 º C (400 º C / min), placed in a
crucible without compression.
The produced button is compared to a series of standard profiles, numbered 1 to
9. The FSI will be equal to the number of the profile that most resembles the
button obtained.
1,0 1,5 2,0 2,5 3,0 3,5
4,0 4,5 5,0 5,5 6,0 6,5
7,0 7,5 8,0 8,5 9,0

Gieseler Plastometer (ASTM D2639)
Measure of the bonding properties of coal.
Measure the rotation of an agitator (subjected to a torque) within a compressed
load of 5 grams of coal 35 mesh (-0.42 mm). Register, as the coal is heated to
3° C / min between 300 and 500 °C, the fluidity in dial divisions coupled to an
agitator.
Temperature (°C)
Maximum fluidity
Fluidity
(ddpm)

Audibert-Arnu Dilatometer (JIS M 8801 DIN 51739)
Monitoring of volumetric changes undergone by a binder coal during plastic
stage.
Coal sample 0.15 mm, compressed in the form of a pencil with small taper (6.5
mm in diameter and 60mm long) is inserted into a metal tube. Over the pencil is
placed a piston coupled to an extension bar (weight of 150g on the pencil). It is
analysed the length variation of the pencil heated at 3 °C / min between 300 and
500 °C.
Temperature (°C)
Ta
Tr
Expansion (%)
Contraction
(%)

Coke Reactivity Index - CRI
Definition: The rate or speed that carbon coke reacts
with an oxidizing gas (O2, CO2, H2O, etc.).
Specification: 18,5 a 27,5%
The reactivity of coke can be evaluate by the weight loss suffered by
a sample of coke subjected to a flow of CO2.
The reaction with CO2 in the highest part of the furnace is strongly
dependent on the type of coke and consumes about 25 to 30% of the coke put
into the furnace, and have a decisive influence on the performance of
Blast Furnace.

Coke Reactivity Index - CRI
CRI = Mi – Mr . 100
Mi
Legend:
CRI: coke reactivity index (%)
Mi: sample initial mass (g)
Mr: sample reacted mass (g)
This index indicates the weight loss of a 200g coke sample, after the passage of
CO2 for 2 hours at 1100 ºC.

Coke Strength after Reaction with CO2 - CSR
A resistência do coque após a reação, CSR, é avaliada submetendo-se
a massa de coque, após ensaio de reatividade, a 600 rotações durante
30 minutos em um tambor tipo “I”, seguido de peneiramento na malha
de arame de 9,50 mm. Especificação: 62,0 a 75,0%
Ensaio CSR:
O equipamento utilizado no ensaio de CSR é acionado por um motor-
redutor de velocidade fixa, de forma a se obter 20 rpm e dispõe de um
contador de giros que desliga o equipamento quando se atinge 600
giros durante 30 minutos.

The coke strength after reaction, CSR, is evaluated by submitting
the mass of coke after reactivity testing at 600 rpm during
30 minutes in a drum type I followed by the screening in the wire mesh
of 9.50 mm.
Specification: 62.0 to 75.0%
CSR testing:
The equipment used in testing of CSR is operated by an reducer motor with
fixed speed in order to achieve 20 rpm and has a
turning counter that switch off the equipment when it reaches 600
turns for 30 minutes.

CSR = Mrm . 100
Mr
Legend:
CSR: coke strength after reaction with CO2 (%)
Mr: sample reacted mass(g)
Mrm: retained mass in the mesh of 9.50 mm (g)

Importance of CRI and CSR Specification
The specification of the CRI and CSR are related to minimizing the endothermic
reaction between coke and CO2 in the blast furnace shaft and ?need to ensure
high strength, less degradation, and ?therefore, high permeability in the region of
the bosch.

Drum Index (DI)
Ability to resist the impact fragmentation and / or abrasion in tumbling tests,
determining the extent of its reduction in particle size after being subjected to a
fixed number of revolutions in a drum with standard features and expressing the
test results in the form of several indexes related of coke (after tumbling) retained
or passing in a determinated mesh
Specification
83,0 DI 89,0%

Resistance Tests
Drum Micum IRSID JIS ASTM
Regulation M03-046 M03-046 K2151 D294-64
Coke size (mm) 60 20 25 51-76
Sample weight (Kg) 50 50 10 10
Drum dimensions
(m)
1,0 x 1,0 1,0 x 1,0 1,5 x 1,5 0,914 x 0,457
Rotation speed (rpm) 25 25 15 24
Total of revolutions 100 500 150 1400
Mesh (mm) 60,40,10 40,20,10 50,25,15 25 a 6
Hole meshes round round square square
Results expression M40 e M10 I40, I20 e I10 DI
150
15
Stability (+25 mm)
Hardness (+ 6mm)

Moving Wall Coking Test Oven
Represents an individual cell of a horizontal furnace.
There are no standard methods of determining coking pressure.
Coking time (h)
Coking
pressure
(psi)
1
2
3
4
5
1 2 3 4 5 6 7 1 9
Max
pressure

Heated Base Oven (ASTM D2014)
Measurement of volumetric variations of the load, heated unidirectionally under
2psi pressure.
As the load is not under in volume confinement, the variation in height can be
positive (expansion) or negative (contraction).
Heated base
(SiC resistance)
Coal
Piston
Refractory
2 psi

Coke Basic Composition:
Fixed Carbon 85%
Ash 12%
Volatile Matter 1 a 2%
Total Sulphur 0,40%
Moisture 1%

Coking Process in Horizontal Furnace

1
Companhia
Vale do Rio Doce
COKEMAKING PROCESS
Uses of Coal in Cokemaking Process

2
Companhia
Vale do Rio Doce
PART X
IRONMAKING COURSE
Uses of Coal

Uses of Coal and the Future of Coke
Heating Value
LOW RANK COAL
48%
HARD COAL
52%
LIGNITE
20%
SUB-BITUMINOUS
28%
HIGH
BITUMINOUS
51%
ANTHRACITE
1%
STEAM
THERMAL COAL
METALLURGICAL
COKING COAL
¾Electricity generation
¾Cement making
¾Industrial uses
¾Mainly for electricity
¾generation
¾Pig iron and
¾steel making
¾Industrial use and
¾as smokeless fuel
HIGH
Moisture
USES OF COAL
(WORLD COAL
INSTITUTE)

Uses of Coal and the Future of Coke
¾ The main function of the coke in the blast furnace is as “process
permeabilizer”. Without that function it would not be possible the iron-making in
the blast furnace. Worldwide the production of hot metal and crude steel via
the blast furnace/converter route is regarded as the dominant process line also
in the next two or three decades (there's no metal-production system that can
beat the blast furnace). In other words, the coke still has an on-life at least
equal.

Coke in the Production of Hot Metal (I)
¾The principle of iron-making in a blast furnace is that iron ore is reduced by carbon
from coke to form metallic iron and carbon dioxide. The production of hot metal in an
integrated steel plant involves three basic units: coke oven, sintering and blast
furnace.
Coke Oven Gas and By-Products
Blast Furnace Top Gas
Fine Iron Ore
Coking Coal
Anthracite
Sinter
Pulverised Coal
Blast Furnace
Breeze
Fluxes
Hot Metal
Slag
Coke Oven
Sintering
Coke and Small Coke
Lump Iron Ore

Coke in the Production of Hot Metal (II)
¾By-Product Cokemaking. The process is developed in a wet-charge, by-product coke
oven and is comprised of the following steps: i) the coals are reclaimed from
stockyards, crushed in hammer or impact mills to about 85% under 7 mesh and
mechanically blended according to a formula of a multi-component coal blend, iii) the
coal blend is charged into a number of slot ovens wherein each oven shares a common
heating flue with the adjacent oven and iv) coal is coked at a temperature of about
1250°C for about 18 hours in the absence of air and the off-gas is collected via the
ascension pipes and crossover mains to the by-products area, where it is cooled,
scrubbed, and many valuable by-products are extracted.

¾ Coal-to-Coke Transformation Steps: i) the heat is transferred from the
heating walls (indirect heat is applied by means of gas firing) into the coal
charge, ii) from about 350°C to 475°C, the coal decomposes to form plastic
layers near each wall (during the plastic stage, the plastic layers move towards
the centre of the oven trapping the evolved gas and creating a gas pressure
build up which is transferred to the heating wall and is traditionally known as
coking pressure), iii) at about 475°C to 600°C, there is a marked evolution of
tar, and aromatic hydrocarbon compounds, followed by solidification of the
plastic mass into semi-coke, iv) at 600°C to 1100°C there is a contraction of
coke mass, structural development of coke and final hydrogen evolution. The
incandescent coke mass is pushed from the oven and is wet or dry quenched
and then transported to the blast furnace.

Coke in the Production of Hot Metal (III)
¾Non-Recovery Coke-Making. Coal is carbonised in large oven chambers and the
coking process takes place from the top by radiant heat transfer and from the bottom
by heat conduction through the sole floor. Primary air for combustion is introduced
into the chamber through ports located above the charge level in both pusher and
coke side oven doors. The volatile compounds that are produced during the
carbonisation of coal are oxidised in the oven chamber and partially combusted
gases exit the top chamber through down comer passages in the oven wall and
enter the sole flue, thereby heating the sole of the oven. Combusted gases are
collected in a common tunnel and exit via a stack which creates a natural draft in the
oven. Since the by-products are not recovered, the process is called non-recovery
coke-making (if the waste gas exits into a waste heat recovery boiler which converts
the excess heat into steam for power generation it is named non-recovery-heat
recovery). In-oven combustion of hydrocarbons appears to virtually eliminate
hydrocarbon emissions and also the negative-pressure ovens should not leak
appreciable amounts of emissions.

Coke in the Production of Hot Metal (III)

¾Sintering is a process in which iron ore fines (in a mixture with several recycled
materials, fluxes and solid fuel) is agglomerated forming a porous mass (sinter) that
it is fed in the blast furnace as component of the mineral burden. In the process the
mixture is ignited by a gas burner and then moved along a travelling grate machine
until partial melting and agglomeration of iron ore particles occur. The burning of
coke breeze resulting from the process of blast furnace coke calibration and sized in
rod mill to below 4.76 mm (in mixture with other solid fuels as anthracite, wood
charcoal or green pet coke) provides the heat for the process.
Coke in the Production of Hot Metal (IV)

¾The purpose of a blast furnace is to chemically reduce and physically convert iron
oxides into liquid iron called “hot metal or pig iron”. Blast furnace is a chemical
reactor which requires certain physical conditions such as permeability to fluid flows
in order to produce hot metal efficiently. From the tuyere level and above, it is a
counter-current reactor. The descending solids are processed by the ascending gas
which carries heat and reducing agents, H2 e CO. Coke is used as reducing agent,
fuel and permeability provider.

Coke in the Production of Hot Metal (V)
¾ The main blast furnace product is iron in melted state that it is called hot metal
or pig iron. Hot metal is sent for the steel plant of an integrated steelmaker and
fed in converters. Pig iron is iron liquid solidified in metallic ingot molds (pig
iron is called like this since when the liquid iron was drained through a channel
in the soil to flow in molds and whose arrangements resembled with avid newly
born pigs to suck).

Coke in the Production of Hot Metal (VI)
¾Iron bearing materials (iron ore, sinter, pellets), coke and fluxes are charged into the
top of the furnace. A blast of pre-heated air enriched with oxygen and also, in most
cases, a gaseous, liquid or powdered fuel (for instance, pulverised coal) are
introduced through openings (tuyeres) at the bottom of the furnace just above the
hearth crucible. Coke and mineral burden are charged in separate and alternate
layers and nowadays all steelmakers are mixing small coke or nut coke with the
mineral burden (iron bearing materials + fluxes). The heated air burns the injected fuel
and most of the coke charged in front of tuyeres to produce the heat required by the
process and to provide reducing gas that removes oxygen from the ore. The reduced
iron melts and runs down to the bottom of the hearth. The flux combines with the
impurities in the ore to produce a slag which also melts and accumulates on top of the
liquid iron in the hearth. The melted iron and slag are both tapped periodically of the
furnace. The total furnace residence time is about 6 to 8 hours.

Coke in the Production of Hot Metal (VI)
Carbon Blast Furnace Reactions
Carbon oxidised by hot air:
Carbon(s) + oxygen(g) → carbon dioxide(g)
C(s) + O2(g) → CO2(g)
Carbon oxidised by carbon dioxide:
Carbon(s) + carbon dioxide(g) → carbon monoxide(g)
C(s) + CO2(g) → 2CO(g)
Carbon monoxide reduces iron (III) oxide
Carbon monoxide(g) + iron (III) oxide(s) → iron(l) +
carbon dioxide(g)
3CO(g) + Fe2O3(s) → 2Fe(l) + 3CO2(g)

¾After extinction coke is transported to the blast furnace in a handling system
constituted by belts conveyors, transfer chutes, screens and bunkers (the
handling system in the figure proceed is from Brazilian Usiminas steelmaker). In
this system coke suffers mechanical stabilisation due to the drops that is
submitted (few companies have coke cutters for size reduction, even if its
stabilisation in the handling system is not enough). Coke is classified in two or
three products that are used in the blast furnace and sintering. As an example i)
coke breeze under 10 mm is used after rod mill size preparation in sintering, ii)
small coke (10 - 25 mm) or nut coke (25 - 40 mm) is used as component of
metallic burden in the blast furnace and iii) lump coke (25 - 75 mm or 40 - 80 mm)
in the blast furnace coke bed (coke layers) as main responsible for the furnace
permeability.
Coke in the Production of Hot Metal (VII)

Coke in the Production of Hot Metal (VII)
AF3
AF2
AF1
Bateria
2
Rampa
Bateria
1
Rampa
Bateria
4
Rampa
Bateria
3
Rampa
K
203-1
K
207
K
208
K
210
K
211
K 211r
K
103-1
K
103-2
K
105
K 106r
K 104-r
C 2
C 4
E 4
E 2
C
1
E
1
C
3
E
3
K 202r K 102r
Coke
Bunker
S
1
C2
C1
C3
Finos para
Sinterização
CT C-4
CT C-3
CT C-5
Finos para
Sinterização
Skip
CT C-4
CT C-3
CT C-5
Skip
Finos para
Sinterização
Peneiras
K
203-2
K 204-r
K 105-A

¾Hot metal production in the blast furnace is linked with coke and its availability.
A blast furnace cannot be operated without coke for physical reasons and the
coke is generally the most expensive blast furnace burden material. The blast
furnace operator will therefore always try to reduce coke consumption to the
lowest level technically possible by injecting coal or other reducing agent. But for
this they need to place more rigid quality requirements on coke.
Coke Role in the Blast Furnace (I)

Coke Role in the Blast Furnace (I)
¾ The quality of the coke can be defined as being its capacity to fill out the
requirements demanded in the blast furnace and for an appropriate definition it
is necessary to know i) the coke roles in the blast furnace and ii) the factors
that act on the coke inside the blast furnace. The coke, besides having low
contents of contaminants of the hot metal (S and P) and/or of operation
disturbing elements (Na, K and Zn), should be capable to perform three main
roles in the blast furnace: a thermal, a chemical and a physical role.
Role 1: Thermal
ˆ Provision of fuel for combustion in the raceway region.
Role 2: Chemical
ˆ Reacting with CO2 it provides the reducing gases for the reduction of iron.

™ Role 3: Physical (coke is the great provider)
¾Provides a permeable bed at the top of the furnace for gas to pass through.
¾Parts the heavier, denser and less permeable layers of mixed pellets, lump
ores, sinter and fluxes (nowadays the small coke or nut coke is part of those
layers).
¾Provides a permeable matrix (windows) in the lower part of the furnace
through which liquids can drip and hot gas pass.
¾Support the weight of stock.
¾Provides a permeable bed for iron and slags to flow to the tap holes of the
blast furnace.
Coke Role in the Blast Furnace (II)

Coke Role in the Blast Furnace (II)
Coke can be replaced to a large degree in the first two roles by, for instance,
by pulverised coal.
The physical role is dependent on the size, size distribution, shape and
superficial irregularity of the coke.
The maintenance of a good permeability in the several zones of the blast
furnace is dependent of the strength, coke strength after reaction, amount of
recycled alkalis inside the blast furnace etc.

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