Lecture notes of Industrial Waste Treatment (Elective -III) as per syllabus of Solapur university for BE Civil Prepared by Prof S S Jahagirdar, Associate Professor, N K ORchid College of Engg and Tech, Solapur

1. L-29
Steel mill
Industrial Waste Treatment

2. Introduction
• Steel industry uses large amount of
water and discharges wastewater in
proportion.
• Wastewater contains SS, lubrication oils,
and several toxic substances.and several toxic substances.
• There are seven major integrated iron
and steel plants in India, out of which
five are under the Steel Authority of
India Ltd. (SAIL)

3. • The total world annual production of
steel is 715.4 million tonnes of which
India contributes 14.5 million tonnes. In
India, on an average each tonne of
steel production consumes 25 to 60
cubic meters of water and 4 to 5
tonnes of other raw materials. It maytonnes of other raw materials. It may
be noted that in developed countries the
water consumption for each tonne of
steel production varies from 3 to 6 cubic
meters, i.e., 8 to 10 times less than that
of water consumption in India.

4. • In an Integrated Iron & Steel
Industry, wastewater generated from
Coke Oven By-product Plant is
considered to be the most
polluting.
• This wastewater contains toxic• This wastewater contains toxic
chemicals like phenol, cyanide and
ammonia, which are harmful to the
receiving water bodies when
discharged untreated/partially
treated.

5. MANUFACTURING PROCESS

6. IRON ORES
ORE APPEARANCE COMPOSITION % OF IRON
MAGNETITE STEEL GREY OR BLACK Fe3O4 72-62
HEMATITE
(a) RED HEMATITE EARTHY OR ROCK ,RED Fe2O3 70-60
(b) BROWN HEMATITE BROWN EARTHY 2 Fe2O33H2O 60-42
SIDERITE OR SPATHIC CRYSTALLINE GREY FeCO3 48-35
IRON STONE GREY TO LIGHT BROWN FeCO3 42-30
EARTHLY OR STONEY

7. MAGNETITE:
HEMATITE:(RED)
HEMATITE:(BROWN)

8. • Pig iron:- is the intermediate
product of smelting iron ore with a
high-carbon fuel such as coke,
usually with limestone as a flux.
Charcoal and anthracite have also
been used as fuel.been used as fuel.
• Pig iron has a very high carbon
content, typically 3.5–4.5%, which
makes it very brittle and not useful
directly as a material except for
limited applications.

9. Pig iron
• Traditionally
pig iron would
be worked into
wrought iron in
finery forges,
and later
puddlingpuddling
furnaces, more
recently into
steel

10. Ingot
• An ingot is a material, usually
metal, that is cast into a shape
suitable for further processingsuitable for further processing

11. Billet Mill
• A rolling mill designed
for the rolling of blooms
or ingots into billets of
square or round cross
section.section.
• The billets are later
processed in specialized
rolling mills (section and
tube rolling mills).

12. Rolling
• In metalworking, rolling is a metal
forming process in which metal stock is
passed through a pair of rolls. Rolling is
classified according to the temperature of
the metal rolled.
• If the temperature of the metal is above
its recrystallization temperature, then the
process is termed as hot rolling.
• If the temperature of the metal is below
its recrystallization temperature, the
process is termed as cold rolling.

14. PICKLING
• The process of removing hot rolled
mill scale from billets, bars or hot
rolled sheets with sulphuric or
hydrochloric acid.hydrochloric acid.
• The scale is removed for hot rolled
pickled and oiled sheets or for further
processing of the hot rolled steel
product into cold drawn bars and wire
and cold rolled sheets and strip.

15. Blooming Mill
• Blooming Mill a high-capacity rolling
mill for the reduction, into blooms, of
steel ingots of large cross section, with
masses up to 12 tons and larger.
• In some cases a blooming mill is used• In some cases a blooming mill is used
for the rolling of slabs and also shaped
pieces (for heavy I beams, channel iron,
and the like).

24. Treatment
• Segregation
• Equalization
• Clarification• Clarification
• pH adjustment
• Precipitation
• Filtration

27. Theory Questions
Q1. Draw process flow sheet of steel
mill.
Q2. discuss nature of waste from steel
mill and suggest treatments.mill and suggest treatments.