1. MINERAL MATTER IN COAL
Submitted to: Dr Naseer A Sheikh
Submittedby: Navira Younas
Roll NO# 22
CENTRE FOR COAL TECHNOLOGY
16/03/2015

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INTRODUCTION:
The mineral matter in coal in
coal includes minerals and other inorganic minerals
in, and associated with, macerals. There are more
than 150 species of minerals already identified in
coal. However, the species of common minerals
found in most coals are few. CLAY MINERAL is
spread widely and is highest content.
While common minerals several microns may
scatter in macerals. The elements identified in coal
number 86 and include many inorganic elements,
ions, and compounds that may be associated with
organic matter, dissolved in pore are QUARTZ,
PYRITE, CALCITE, DOLOMITE, SIDERITE, and
ANKERITE.

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Mineral particles smaller than water, or mixed with
coal bed gas. During the coalification process
mineral matter can be transferred into or out of
coal bed. Some of these minerals are no doubt
terrigenous detritus, and some are chemical and
biochemical authigenic minerals. The minerals of
other origins are few. Minerals of different origins,
or which formed in different ages often co-exist in
the same seam. The mineral matter in coal is the
geochemical indicators of coal. The minerals and
other inorganic matters in coal are the important
factor for assessing the coal quality in coal mining,
preparation, storage, coking, gasification,
liquefaction, and other applications. Environmental
problems are caused by mineral matter are being
given greater and greater attention. Coal with high
contents of some minerals matter is the noticeable
source of metals and non metal.
The
amount mode of occurrence and composition of

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mineral matter in coal are factors of great practical
importance in determining its market acceptability
and economic value. The yield and qualities of
products obtainable by cleaning the coal are also
dependent upon the characteristics of mineral
matter.
TYPES OF MINERAL MATTER
According to its mode of origin, mineral matter
within a coal seam may be classified into the
following two categories:
1. Inherent mineral matter
2. Extraneous mineral matter( adventitiousmineral matter )
INHERENT MINERAL MATTER:
Consisting of organic
constituents that previously formed part of tissues of the
plants forms which the coal was derived. Most mineral

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matter is chemically or colloidally combined with coal
substance.
EXTRENOUS MINERAL MATTER:
Derived from sources
outside the swamps in which coal forming plants
decayed. Extraneous mineral matter generally consists of
large bits and pieces of inorganic materials typical of
surrounding geology. In some cases the extraneous
matter is so finely divided and uniformly dispersed within
the coal it behaves as inherent mineral matter. Coal
preparation can separate some of the extraneous matter
from coal substance, but it seldom removes any of
inherent mineral matter.
Extraneous mineral matter can behave as discrete
mineral particles comprised of single specie or a
multiplicity of specie. As already indicated, a portion of
this material may be so finely divided it can behave as
inherent mineral matter.

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Extraneous mineral matter occurs in following
forms:
1.In chemical or colloidal combination with
coal substance.
2.As fine particles, often disseminated fairly
evenly throughout the coal.
3.As parting, bands and lenticles of
mudstone, shale, siltstone, sandstones etc.
4.As material that has been introduced into
peres, fissure, and planes of weakness in
the seam during coalification.
5.As mineral matter derived from strata
above or below the seam.
MINERAL MATTER ENTERS INTO COAL:
There were four means of deposition of mineral matter
into the coal:
Rock sediments from outside, during the flooding
period, were transported by wind and water into
swamps, where coalification process was in
progress.

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Some mineral matter mixed with coal from swamps
during coalification process in-situ and some mineral
matter also mixed up with coal when it drifted from
its original location and entered the swamps or
shallow marshy lands.
Very fine or colloidal form of mineral matter, in
shape of silt, was absorbed by porous coal and
deposited deep in the coal matrix.
During coalification process, mineral matter
deposited into coal by peculating water wherefrom
metal cations entered the coal structure and cause
various ion exchange processes.
R-OH + Na ----------- RO-Na + H
2RCOOH + Ca --------- Ca(RCOO)2 + 2H
CLASSIFICATIONOF MINERAL MATTER IN
COAL:
Genetically they are classified into 3
forms:
1.Detrial

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2.Syngenetic
3.Epigenetic
DETRIAL MINERALS:
Detrial minerals are those that
were deposited in a coal forming peat swamp from
slowly moving water or wind current. Flakes of illite
clay and microscopic grains which become
interbedded with peat and ultimately with the
resultant coal.
SYNGENETIC MINERAL:
Syngenetic minerals are those formed
within the peat during early stages of coal formation,
before peat was deeply buried by other sediments,
probably by not more than 50 ft. under these
conditions disseminated pyrite is thought to have
formed n sulphate bearing peat by bacterial
reduction of sulphur.

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EPIGENETIC MINERAL:
Epigenetic minerals are mainly
those found in fissure and void fillings. Much of the
calcite in coal as well part of pyrite and kaolinite in coals
are recognized as epigenetic.
Minerals occurring in coal classifiedinto
5 main groups:
Shale
Clay
Sulphur
Carbonates
Quartz
SHALE:
Shale usually the result of the consolidation of
mud, silt, and clay, consists of many minerals including
illite and muscovite, these are forms of mica. Kaolinite
is mostcommon clay material.
SULPHUR (PYRITE):

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Sulpur mainly present as pyrite with
some marcasite. Marcasite has the same chemical
composition as pyrite but a different mineralogical
structure. Sulphur is also present as organic and
sometime as sulphate.
Amount of sulphate sulphur in coal is 0.01 %. 60% of
sulphur in coal is pyrite, when sulphur concentrations
are low. At higher concentrations it may high as 70 to
90%.
Pyrite occurs in coal in wide variety of shapes and
sizes:
Rounded masses called sulphur balls and nodules
an inch or more in size.
Lens shaped masses which are thought to be
flattened sulphur balls.
Verticals, inclined veins or fissure filled with pyrite
ranging in thickness from thin flakes to several
inches thick.
Small, discontinuous veinlet of pyrite, a number of
which sometimes radiate from a common centre.
Small particles or veinlet disseminated in the coal.

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MICROSCOPICALLY:
It is divided into 5 basic types:
Frameboids
Isolated euhedral crystals
Nonspherical aggregates of euhedral crystals
Irregular shapes
Fractured filling
CARBONATES:
Carbonates are mainly calcite, dolomite, or
siderite. The occurrence of calcite is
frequently bimodal.
QUARTZ:
The inherent silica retained in the char as
quartz or silica released from kaolinite and illite at low
temperature. Approximately 35-40% of volatilized
mineral was silica. The next largest component was Iron.
DRAWBACKS OF MINERAL MATTER:

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The mineral matter, especially extraneous, is harmful if it
is not removed from coal to an acceptable limit. The
harmful effects are:
Too much mineral matter creates a lot of problems in
burning. Problems include corrosion, deposition,
slagging and fouling.
If coal with high mineral matter is burned, it produces
a lot of ash and its disposal become expensive.
Due to high mineral matte, heating value is low.
If mineral matter contains heavy metals such as Hg, As,
Pb etc, become very harmful.
ACID MINE DRANIGE:
When pyrite is exposed to air,
oxidation of iron sulfhate occurs
along with production of hydrogen
which creates an acidic
environment.
Mineral matter may contain Uranium, dangerous for
health and environment.
Due to high amount of mineral matter, clinker
formation increases.

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High pyrite in mineral matter causes spontaneous
combustion of coal.
Too much alkali metal in mineral matter decreases
resistivity of ash in burning coal furnaces.
EFFECT OF PYRITE:
 The catalytic activity of pyrite ore from coal
mining was studied in the direct liquefaction process
of high volatile bituminous coal from the south of
Brazil. The process consisted of mixing pulverized
coal with tetralin in the presence of catalyst. It was
possible to obtain fractions of preasphaltenes,
asphaltenes, and oils. Pressure had little influence on
the direct coal liquefaction process, while
temperature had a strong effect on liquefaction
yields. The results of total conversions obtained
were nearly 16 % at 300 °C, 26.5 % at 350 °C and
38.5 % at 380 °C, in spite of high inertinite-group
macerals content (34 vol.%). The pyrite ore catalyst
had a fundamental role in this reaction, leading to

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thermal cracking of the coal structure and
hydrogenation of the fragments. However, the most
significant result related to catalyst presence was
the increase in selectivity of the oil fraction.
 To estimate the influence of mineral matter in coal
on coal combustion, fluidized bed combustion (FBC)
and pulverized coal combustion (PCC) were
simulated by simple models. The theoretical calorific
values of some hypothetical coals of different rank
and mineral matter content were calculated. The
calculated calorific values of coals tend to decrease
with increasing mineral matter content. This is due
to endothermic reactions of decomposition of the
mineral matter as well as the heat capacities of such
minerals. The resulting combustion energy loss can
be very large. A new approach to the calculation of
the calorific value of coals is also proposed.
MINERAL MATTER IN PAKISTANI COAL:

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There are sources of coal in Pakistan such as Thar. In
Pakistan almost all provinces have coal deposits.
THAR DEPOSIT:
Moisture (%) 29.60-55.50
Ash contents 02.90-11.50
VM 23.10-36.60
GCV 6244-11045
LAKHRA DEPOSIT:
Moisture (%) 09.70-38.10
Ash 04.30-49.00
VM 18.30-38.60
GCV 5503-9158
DUKI DEPOSITE:
Moisture (%) 03.50-11.50

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Ash 05.00-38.00
VM 32.00-50.00
GCV 10131-14164