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ABOUT KERALA MINERALS AND METALS LTD.

Kerala has one of the richest and one of most extensive heavy mineral deposits in the

world. These deposits stretch along the seacoast between Kayamkulam and

Neendakara, a trait generally known as Chavara coast. The main constituents in the

deposits are Ilmenite, Rutile, Leucoxene, Sillimanite, Zircon and Monazite. The first

three viz Ilmenite, Rutile and Leucoxene are titanium bearing minerals and hence

used for the manufacture of titanium dioxide pigment and titanium sponge metal.

In 1932, a company named M/s. F.X. Pereira and Sons Travancore Pvt. Ltd was

registered. Mineral sand mining and Ilmenite separation was started by them. In

1972 this company was taken over by Kerala Government and was renamed as The

Kerala Minerals and Metals Limited.

In 1974 permission for the manufacture of TiO2 pigment was procured and the project

work started in 1979, with the technical support of foreign companies like M/s.

Benelite Corporation of America, M/s. Woodall Duckham of U.K. and M/s. Kerr Mc

Gee Chemical Corporation of MEA. TiO2 pigment production was started in the

Pigment Production Unit at KMML by Chloride Process. Now the capacity of the

plant has been increased to about 40,000 TPY.

KMML is the only company in the whole world where the plants for mineral sand

mining, separation, beneficiation and TiO2 production are erected under a single roof.

KMML produces mainly five grades of TiO2pigment. The main consumers of the

product are the paint, paper, printing ink and rubber industries.

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ILMENITE BENEFICIATION PLANT (IBP)

Ilmenite Beneficiation Plant (IBP) is designed and installed based on the BCA Cyclic

Process Technology data furnished by their associates M/s. Multi Resources

International Corporation.

The rated capacity of the plant is 45,000 TPY of Beneficiated Ilmenite (BI) containing

a minimum of 90-92% TiO2 which is the raw material for the pigment production

unit, using Quilon Grade Ilmenite as raw material. The plant is in a single stream.

The basic raw materials are:

Raw Ilmenite

Lecofines

HCl

Beneficiated Ilmenite also called Synthetic Rutileis used as the raw material in

Pigment Production Plant (PPP) and TiO2 is manufactured through Chloride

Technology. The IBP is divided into three major sections

(a) Roasting and Cooling Section

(b) Digestion and Filtration Section

(c) Calcination and Cooling Section

PROCESS DESCRIPTION

Here, Raw Ilmenite (RI) is collected form sea washing, processed and synthetic rutile

is manufactured and TiO2 is produced. The basic raw material, Raw Ilmenite is

conveyed from the respective storage building to hopper through a system of

conveyors and bucket elevators. Another solid raw material, petroleum coke which is

used as reductant, is conveyed through conveyors and bucket elevators to another

hopper

(a)Roasting and Cooling Section

In the roaster, the chemical reaction is reduction. Reduction is the process by which

the oxygen content of mineral is lowered by heating in a controlled atmosphere. The

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reductant used here is Lecofines. It supplies carbon for reduction. Raw Ilmenite and

Lecofines are fed to a rotary kiln called roaster where the temperature is maintained at

about 900-9500C for reduction to get Reduced Ilmenite (REI) which is then cooled in

a cooler to about 800C. About 80% of Fe2O3 present in Raw Ilmenite is converted to

FeO during reduction. Heavy fuel oil burner directly fires the roaster. Here counter

current operation takes place. Feed is send through one end, and at the discharge end

fuel oil is fired at 1200C. Fuel oil should be maintained at 1200C, otherwise it will be

solidified.

Combustion gases flow counter currently to the feed. Most of the total theoretical air

required for complete combustion is provided through the burner by primary air fan.

The secondary air fan supplies the remaining theoretical air and also some excess air

through an insert pipe, which is inserted from the discharge end of kiln. The excess

air burns out with part of reductant and helps to reraise the Ilmenite bed to reducing

temperature for sustaining perfect reduction. Part of the flue gas from the kiln is

recycled by recycle fan. The recycled flue gas is used to maintain reducing

conditions.

The kiln exhaust gases pass through a dust cyclone to recover the carry over dust and

a quencher scrubber where ash and any fuel carried over as vapor or mist is scrubbed

out with water and in the process the exhaust gases are also cooled down. The

cleaned exhaust gases are sucked off by the draft fans and discharged through the

stack to the atmosphere.

The hot Reduced Ilmenite (REI) discharged from the kiln is directly sent into a rotary

water cooler where it is first quenched by direct water spraying. Due to this steam is

generated preventing hot Ilmenitefrom reoxidation. The material is further cooled to

about 1500C by circulating water through the cooler tubes. The outlet water from the

cooler tubes is sprayed on the cooler shell at the free end. The REI leaving the cooler

may contain small agglomerates and unburnt Lecofines, which are separated on the

vibrating screen. The product is then transferred to RI storage hopper though belt

conveyor and bucket elevator.

The Ilmenite roasted in reduced atmosphere convert majority of Ferric oxide present

as impurities in the Ilmenite to more easily leachable Ferrous oxide. The main

reactions taking place here are:

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2C+O2 2CO

C+CO2 2CO

Fe2O 3+C 2FeO + CO

Fe2O 3+CO2 FeO+CO2

(b)Digestion and Filtration Section

The Reduced Ilmenite is taken to the digester section. Digester is a spherical batch

operator vessel where leaching process called selective adsorption is carried out. The

principle of leaching is that the material that is leaching should be immiscible with the

leaching liquor.

The Reduced Ilmenite is leached twice with 19-20% HCl obtained from Acid

Regeneration Plant mixed with commercial HCl from TCC in digesters at 1430C.

There are two leaching stages. For the first stage 51m3 of HCl is used and for second

stage 42m3 of HCl. Acid leaching of reduced Ilmenite is to remove iron compounds

and other undesired matters in the heat of the processing for producing upgraded

Ilmenite.

FeTiO3 + 2HCl →FeCl2 +TiO2 + H2O

During the reaction TiO2 content in the Ilmenite is increased from 59% to 93% and all

Ferrous oxide, part of the Ferric oxide, part of other oxides like Manganous oxide,

Magnesium oxide etc. are dissolved in the acid which is sent to ARP for recovery.

Part of Cr2O3 and V2O5are also removed but SiO2 and ZrO2are remained with

TiO2.The basic leaching process is controlled by the acid to Ilmenite ratio, pressure

and temperature of the digesters during leaching and the leach cycle time.

The leached Ilmenite after washing with 50m3 wash water is dumped into the

launders. From the launder it is pumped as slurry and filtered through a horizontally

moving vacuum belt filter. The filter cake is washed with water to remove most of

acid present. This product called leached Ilmenite is then passed to the calciner

through belt conveyors.

To increase the TiO2 content, more concentrated acid can be used, but the problem is

that fines generated with be more and will go through the filtrate or overflow and so

19.5% acid is used for the leaching. The weightage of Ilmenite will be less after

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leaching due to removal of Fe compounds. Thus from 1.66 ton Raw Ilmenite 1 ton of

Beneficiated Ilmenite is manufactured. The chemical reactions taking place during

leaching are:

FeO + 2HCl → FeCl2 + H2O

Fe2O3 + 6HCl → 2FeCl2 + 3H2O

Acid Liquor Treatment Section:

The spent liquor and wash liquor blown down from the digesters are passed through

different series of settling tanks and fines removal system for removal of carry over

Ilmenite solids. The clean spent acid and wash water thus obtained are pumped to the

Acid Regeneration Plant for regenerating the acid. The recovered acids received from

the storage tank are pumped together using ratio controller to get mixed acid of 19 to

20% concentration for using in the digesters. Wash water is used as absorbent.

(c) Calcination and Cooling Section

In the calciner and cooling section, the Leached Ilmenite wet cake is calcined at about

500-5500C to remove moisture from 27% to 0.5% and residual carbonaceous and

volatile matter that are carried over during roasting and leaching process. The hot

product is then cooled to 800C in the cooler.

The wet cake from the belt filter is conveyed to rotary calciner by screw feeder and is

calcined. The temperature to which the material is calcined is 500-5500C, where the

liquid containing HCl acid, the ferric and ferrous chlorides and the carried over

carbonaceous matters are removed. Heavy fuel oil burner directly fires the calciner.

The primary air is supplied by primary air fan and the secondary air by the calciner

exhaust fan. The exhaust gases leaving the calciner passes through a cyclone which is

equipped with steam traps to prevent HCl vapors from condensing. Steam trapping

isused in cold condition during startup. The recovered micro fines in the cyclone are

used as flux in welding electrodes. The vapor leaving the cyclone enters the gas

scrubber, where the gas is scrubbed with recirculating water to remove traces of HCl

present in the exhaust gas and during this operation gas is also cooled. The acid bleed

from the scrubber is sent to wash water blow down tank. The waste gases are then

exhausted by the exhaust fan to the atmosphere through stack. The red hot BI is

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cooled to 800C in rotary cooler by direct contact with counter current flow of air. BI

from the cooler is then screened on the vibrating screen and then allowed to fall on to

the product belt weigh feeder which feeds the material to the bucket elevator and then

to the product transfer conveyor. The BI is then either discharged to the belt conveyor

for onwards transportation of the material to the pigment production plant or dumped

into the BI storage building. No chemical reactions take place during calcination.

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ACID REGENERATION PLANT (ARP)

Acid Regeneration Plant (ARP) is designed to regenerate HCl acid from spent leach

liquor containing some free HCl and metallic chlorides (Fe2+ & Fe3+) obtained from

the digesters after leaching.

The whole system operates under vacuum. The spent liquor from IBP is given to

recycle tank through a level control valve (LCV) which is a pneumatic control valve,

and then to preconcentrater. From the preconcentrater it is given to spray roaster, after

filtration of sediments. In the spray roaster, the liquid spray entering the furnace is

heated by fuel oil and is decomposed to metallic oxides and HCl vapor. Iron oxide is

separated from HCl using dry cyclone and is send to preconcentrater.Theseparated

iron oxide is given to the slurry box through a rotary air lock system where it is

slurried with pond water and is given off to pond itself. Since there is an optimum

temperature for absorption, the temperature has to be reduced. This is done in pre-

concentrator, by exchanging heat with the spent liquor from recycle tank. Also during

the process more and more HCl is converted to vapor form. Then it is given to

absorber through wet cyclone which separates moisture carryover from vapor

Absorber is a packed column with ceramic packing where HCl is absorbed in wash

liquor from IBP at about 90-950C. Maximum absorption of HCl takes place here and

is send to IBP. Some minute % of HCl which is unabsorbed is given to tail scrubber

which is also a packed bed with polypropylene pad rings. Scrubbing is done with

water. HCl is recovered and water vapor is passed out through stack using a blower.

Thus 18% HCl is recovered and it is recycled back to IBP. The main purpose of acid

regeneration is pollution prevention than for the sake of economy.

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Spray Roaster

Roaster is the most important equipment in ARP. It is constructed of carbon steel. The

purpose of roasting is to recover HCl acid from spent acid and to convert Iron

chlorides to Iron oxide.

4FeCl2 + 4H2O + O2 → 2Fe2O3 + 8HCl

2FeCl3 + 3H2O → Fe2O3 + 6HCl

Pre-concentrator liquor is pumped from the recycle tank by the roaster feed pump

through fine filter to the spray boom assemblies at the top of the spray roaster. The

spray booms are each filled with a number of spray nozzles which finely atomize the

liquor into the top of the roaster. There is a fury burner mounted at the bottom portion

of roaster. It is lined inside with material like whytheat C, firecrete material etc. At the

top portion there is no need of lining. Lining thickness increases from top to bottom.

Burner temperature should be at about 13500C.

First the burner is fired with LPG and when there is sufficient temperature to sustain

burning of fuel oil, a flame detector senses the flame. It automatically cuts off the

LPG supply and starts fuel oil spray. Then the burner continues to work on fuel oil.

These burners fire tangentially into the roaster and cause a flow of hot gases to spiral

upwards. These hot gases come into contact with the descending liquor droplets from

the spray nozzles. The hot gases evaporate water and free hydrochloric acid content of

the liquor, the spray dried chlorides then react to form hydrogen chloride and the

appropriate oxide. Most of the resulting oxide is discharged from the base of the

roaster, but some is entrained in the gases leaving out. These gases are passed through

a dry cyclone set before flowing on to preconcentrater. The oxide retained by the

cyclone set is returned to the oxide slurrying box.

Cyclones

The cyclones are used primarily for the separation of solids from fluid and utilize

centrifugal force to effect the separation. Such a separation depends not only on

particle size but also on particle density. It consists of a short vertical cylinder, closed

by a flat or dished plate on top and by a conical bottom. The air with its load of solid

is introduced tangentially at the top of the cylindrical portion. Centrifugal forces

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throw the solid particles out against the wall and drop into the hopper. This iron oxide

is separated and slurried which has a high acid content. This iron oxide after

necessary treatments can be used as ‘red oxide’.

Pre-Concentrator

It is the heart of ARP. It is used for concentrating the spent leach liquor from IBP.

Spent leach liquor from the spent liquor storage tank is pumped to the pre-

concentrator recycle tank. The pre-concentrator recycle pump continuously circulates

liquor from the recycle tank to the preconcentrater. Two important operating

conditions are performed in the pre-concentrator. First of all, the temperature of HCl

from the roaster ranges from 365 to 3750C. The circulating liquor in the pre-

concentrator is made to contact with hot gases coming from the dry cyclone sets. This

results in the hot gases being cooled from about 3750C to 960C, the heat so released

being used to evaporate water from the circulating liquor. The circulating liquor

drains back to recycle tank. Since the optimum temperature for absorption 90-950C is

required, this is done for exchanging heat with spent liquor from recycle tank. Also

during the process, more and more HCl is converted to vapor form. The gases pass to

the absorber through wet cyclone where any remaining liquor is removed and drained

to the recycle tank.

Hydrogen Chloride Absorption

Absorber is a packed bed containing ceramic materials. The gases from the wet

cyclones are passed upwards through the absorber where they are contacted counter

current with absorber feed liquor fed from the top of the absorber head tank. This

results in virtually all the hydrogen chloride content of the gas stream being absorbed

to form recovered acid containing 18.8%. The recovered acid flows by gravity to the

recovered acid storage tanks. The gases from the top of the absorber are then passed

upwards through the tail scrubber, where it is contacted counter currently with tail

scrubber circulating liquor inorder to remove most of the residual HCl content. The

gases pass from the top of the tail scrubber to the exhaust fan through the exhaust fan

damper. The gases from the exhaust fan are discharged into the exhaust stack.

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Oxide slurry system

The oxide from the roaster and dry cyclone is discharged into oxide slurrying box.

The oxide is flushed down through the oxide slurry launder by a copious supply of

water into the slurry tank. From the slurry tank it is pumped to the slurry pond. The

concentration of acid in it is very high. So after necessary treatments it can be used as

red oxide. The water supply to the slurrying box consists of clarified water from the

slurry pond via the return water pumps

Emergency Dump System

It is for maintaining an emergency system to safe guard equipment in case of an

emergency plant stoppage. For maintaining emergency water in the absorber head

tank and automatically controlling water flow to pre concentrator recycle tank during

emergency shutdown

.

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CHLORINATION SECTION

Here Beneficiated Ilmenite from IBP is chlorinated to produce TiCl4 (Tickle).

Chlorine reacts with TiO2 and other metallic oxide impurities in BI in the presence of

petroleum coke at a temperature of about 800-9000C in a fluidized bed chlorinator to

produce chlorides of Titanium and other impurity metals. The chlorides of impurity

metals are removed and TiCl4 is condensed in crude form. This TiCl4 is further

purified to obtain pure TiCl4 liquid, which is stored in storage tanks. The purified

TiCl4 produced in U-200 is used in making TiO2 raw pigment in oxidation section.

The primary vessels in which TiCl4 is produced in U-200 are called chlorinators. The

process adopted here is fluidized bed process. The chemical reactions taking place

here are:

(a) TiO₂(impure)+O₂→ TiCl4+CO₂

(b) TiO₂(impure)+2Cl₂+C→TiCl4+CO₂

(c) TiO₂(impure)+2Cl₂+2C→TiCl4+2CO

The first reaction is endothermic: heat required for this conversion may be provided

insitu by adding carbon to rutile. This carbon will combine with oxygen in the rutile

to form carbon dioxide and carbon monoxide. The second and third reactions

represent the overall reaction.

The chlorination section is subdivided into:

Chlorine storage and Handling

Chlorinators

Waste solids & Fume Scrubbing system

Tickle Condensing System

Vent Gas Scrubbing System

Tickle Purification System

Lime Preparation Plant (LPP)

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Effluent Neutralization Plant (ENP)

Brine chilling Plant

First of all, fire is built in chlorinator using excelsior, charcoal and kerosene. The air

for combustion enters the chlorinator through the bottom. As fire burns vigorously,

coke is added slowly until 1.3m bed height is built and is maintained. Chlorinator is

constructed of mild steel and has a capacity of 800 - 900 tons. It is lined with acid

proof refractory firebrick.

When the coke bed temperature is about 8150C and at a pressure of about 1kg/cm2,

rutile ore or Beneficiated Ilmenite (BI) is fed to chlorinator while coke burns away.

The main impurity in BI is silica. When silica content becomes 40-45% it is drained

off. Chlorine gas is introduced into the bottom of the chlorinator from chlorine storage

tank. The recycled chlorine gas from the oxidation plant is also fed through the

bottom. Chlorine reacts with TiO2, coke and other metallic impurities to produce

tickle and other metallic chlorides.

Ore and coke are fed continuously to maintain the proper composition and level of the

bed since both ore and coke are consumed while chlorine passes through the

chlorinator. The gas from the chlorinator passes through a cross over pipe which is

lined with refractory bricks. There is a water injector on the cross over pipe to remove

Aluminium chlorides. A spray of crude liquid tickle from Crude Tickle Quench Surge

Tank (F-204) cools the gases to about 2000C. This cold gas contains TiCl4, CO2, CO

metallic chlorides as vapors and/ or solid and small particles of coke and ore that are

carried over. The gas stream is passed through cyclones F-201, F-202, F-203 and from

there to the condensing column (D-205). At the bottom of the cyclone the unreacted

ore, coke particles and the metallic chlorides are removed and discharged to a waste

solid sump (F-1569) from where they are pumped to the Effluent Neutralization Plant.

Crude tickle is then cooled with water in a shell and tube heat exchanger enters the

top of the column and condenses the upward flowing tickle gas stream. The crude

liquid tickle then flows by gravity to Quench Surge Tank (F-204) and then to Crude

Tickle Storage Tank (F-205). The gases leaving the top of the condensing column

(D-205) are passed through a water cooled condenser (E-206), a knock out pot and a

refrigerated condenser (E-207). In this, the refrigerant is a mixture of methyl alcohol

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and water. The crude tickle from condensers is sent to F-205. After cooling in the

refrigerated condenser to -200C, the gases are sent to acid scrubber (D-556) and to a

lime scrubber (D-1501). The tailings from acid scrubber are given to Acid Recovery

Plant and from lime scrubber to Lime Processing Plant.

The vent gases are pulled through the scrubber by vent gas blower and discharged

through knock out pot F-1502 and vent stack, further dilute the vent gases by blowing

air through the stack. Crude tickle that has been collected in the Crude Tickle Surge

Tank is 99.5% pure. However this may contain Vanadium oxychloride impurity. So

this must be further purified for use in succeeding oxidation section.

The crude TiCl4is pumped to the reactor D-213 where it is heated and vanadium

chloride gets reacted with the treating oil to form a compound which is separated from

TiCl4 by distillation. The temperature (150-1600C) is maintained in the oil treatment

reactorD-213 by circulating the contents of the reactor through a steam heated

reboilerE-210 and E211.The TiCl4, SiCl4 and SnCl4 vapors boil off and pass through

the heavy ends column E-215. The overhead product pure tickle is cooled in the

heavy ends condenser and some tickle is returned to the column D-215 as reflux and

balance is pumped to storage tanks D-222, D-223 and D-224 and is given as the raw

material to the Oxidation plant.

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OXYGEN PLANT

Oxygen Plant is designed to produce pure Oxygen and Nitrogen from atmospheric air.

The method adopted for separation of oxygen and nitrogen from liquid air is known as

rectification. Boiling point of Oxygen is -1830C and of Nitrogen is -1960C.

Rectification takes advantage of the fact that, usually one of the two components will

be more volatile than the other. Here Nitrogen is more volatile than Oxygen and this

difference in volatility makes it possible for separating Nitrogen and Oxygen from

liquid air.

Process Description:

Atmospheric air is drawn through air intake filter and is compressed in reciprocating

air compressors and cooled to about -100C in Freon refrigeration cooler and moisture

condensed is separated out in a moisture separator. Air is then passed through driers

containing activated alumina and molecular sieves for effective adsorption of

moisture and carbon dioxide.

The dried process air is passed through a heat exchanger where one part is partially

cooled by the cold outgoing gases from the fractionating column. The partially cooled

air at -1490C is then expanded in an expansion turbine where the temperature further

falls to -1620C and pressure to 5.5 kg/cm2. The air then along with fully cooled

partially liquefied air from the heat exchanger is fed to the bottom of the fractionating

column.

In the fractionating column liquid air is separated into oxygen and nitrogen. The

oxygen coming out of the fractionating column is further compressed in an oxygen

compressor to about 4kg/cm2 and supplied to oxidation plant for oxidizing TiCl4.

The nitrogen gas is also compressed to about 14kg/cm2 in a nitrogen compressor and

supplied to various plants. Since the distillation of air is achieved at very low

temperatures the fractionating column, the heat exchanger and expansion tube etc. are

installed inside a metal closure called Cold Box and this cold box is filled with an

insulating material mineral wool to maintain the very low temperatures.

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OXIDATION SECTION

Oxidation section of Pigment Production Plant is designated as U-300. In this plant

Tickle (TiCl4) is vaporized, pre heated and is oxidized with oxygen to produce raw

TiO2 at a temperature of about 10500C. Oxidation is the most important process

section of this plant as the know-how of oxidizing TiCl4 in special oxidizer reactors is

the key to Rutile grade TiO2 pigment production.

This unit is subdivided into following sections.

Aluminium chloride dissolving system

TiCl4 vaporizer system

TiCl4 preheater system

Oxygen preheating system

Oxidizer, KCl feed system and Sand Score system

Reactor Cooling system

DI Water system

Pigment separation system

Chlorine compressor system

Pretreatment and slurry system

Sand handling system

Vent gas system

Turbines

Raw Materials

a. Purified Tickle

b. Oxygen

c. Aluminium chloride

d. Caustic soda

e. Hydrochloric acid

f. Sodium hexa meta phosphate(HMP)

g. Sulphuric acid

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h. Sodium dichromate

i. Potassium chloride fused silica

Process Description:

In this unit purified tickle fromU-200 is mixed with AlCl3 and vapor of this mixture is

oxidized in the oxidizer with oxygen in presence of LPG flame to produce TiO2

pigment. Chlorine which is obtained as a byproduct is filtered, cooled, dried and

compressed before sending back to U-200 for chlorination of titanium ore there.

Pure tickle from tickle storage tank is pumped using tickle transfer pumps (G-235/G-

236) through a heater (E- 323) at temperature of 125 0C to 135 0C to aluminum

chloride dissolving tank (D-303). Pre calculated quantity of AlCl3 is mixed with the

tickle in this tank and agitated using agitator (G-307). This solution after settling is

transferred to the surge tank (D-304) from which the feed material for further process

is drawn. Quantity of AlCl3 to be added varies for different grades of raw pigments

produced.AlCl3 is dissolved in it inorder to prevent agglomeration of the TiO2 formed

during the reaction. Since the vessel is glass lined, the problem of corrosion by AlCl3

is also avoided. Amount of AlCl3 depends on the grade required.

From there, it is sent to vaporizer by gravity. In the vaporizer steam is used to

vaporize liquid tickle. It will become vapor at about 130-1500C. Tickle from vaporizer

is hated to about 3500C in a Selas furnace. It is lined with a special alloy called

Inconel.

TiCl4 + O₂→ TiO2 + 2Cl2

Oxygen from oxygen plant humidified with DI water in U-300 is heated to reaction

temperature (10500C) in Selas make oxygen preheater. TiCl4 and O2 at high

temperature are mixed in the oxidizer where the reaction between TiCl4 and O2 takes

place and TiO2 and Cl2 are formed. Sand blasting is done with a mixture of pure silica

sand (99.9%) and Nitrogen at a high pressure. Now, LPG is burned to maintain

temperature in the oxidizer.

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Inorder to improve the quality of product, here k+ mixture is added. It is a mixture of

carbosilicate, potassium chloride and silica sand. It does the following functions

thereby improving the quality of the product.

K+ mixture involves in the exothermic reaction and makes it

endothermic. Thus temperature control is affected.

It improves white color of the pigment.

It also prevents the agglomeration of TiO2.

The product mixture TiO2 and Cl2 is carried forward through a DI water cooled

reactor cooling tubes, to pigment separators where pigment is separated and dumped

to pretreatment sump for slurrying. The Cl2 gas leaving the separator is further

processed to free it from TiO2 dust, TiCl4, HCl etc. It is then given to bag filter,

chiller, H2SO4 scrubber, compressor etc. and sent back to U -200 for further reaction

with rutile and coke.

The pigment slurry is then classified to remove sand and pumped to slurry storage

tanks. From these tanks, the slurry which is the product of oxidation section (U-300)

is pumped to finishing section (U-400) for treatment to produce pigment product.

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SURFACE TREATMENT AND PIGMENT FINISHING

SECTION

The finished titanium dioxide pigment is produced in this section of the plant. The

raw pigment produced in the Oxidation section in slurry form containing sand is the

main feed to the finishing section. Here the raw pigment is treated with chemicals and

size reduced to impart certain qualities and properties apart from removing all traces

of sand. The finishing section U-400 is the final process section divided into the

following subsections.

Sand milling

Treatment

Filtration and Drying

Micronisation and Cooling

Product Bagging

A number of treating chemicals are added here. The micronized pigment will have

extremely small particle sizes averaging about 0.2 microns. The optimum particle size

of TiO2 pigment is 0.28 microns which is obtained by micronizing the filtered,

washed and dried pigment particles. The micronized product is bagged in paper bags

of 25kg capacity

Sand milling and Classification

Pigment slurry from storage tank is pumped to trash screen where sand and trash are

removed. The screened slurry flows to tank by gravity. From this tank slurry is

pumped to sand mill for releasing absorbed gases like TiCl4 and O2. Sand milled

slurry is pumped to the grits classifier and to vibrating screen to screen out the grits

and sand. Screened slurry is pumped to product classifier. Product classifier separates

5 micron particles and overflow goes to treatment feed tank.

Treatment

In treatment, various chemicals such as sodium silicate, sodium aluminate etc. are

added which when neutralized with caustic soda or sulphuric acid from hydrous

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oxides. Treatment is done in F-415 A or B tank on batch basis which is provided with

steam sparger and agitator having two speeds. Using the pumps required quantity of

raw slurry is pumped to treatment tank. The treatment chemicals from U-500 are

connected to F-415 A or B tank. Required quantity of chemicals can be set in the flow

totalizer. After batch treatment is completed, the whole contents are transferred to F-

418 tank.

Filtration and Drying

Treated slurry is pumped to filter feed tanks. From this tank, slurry is fed to first

stage filter. Cake is formed on the filter drum which is washed by spraying hot water

through nozzle. The cake is discharged to re-pulper. From the re-pulper, slurry goes to

storage tank by gravity flow. It is pumped to second stage filter and after washing and

re-pulping slurry goes to F-424 tank. Pigment slurry is pumped to de-watering filter.

The cake from the dewatering filter is allowed to fall into extruder in which pigment

cake changes into macroni shape which drops into the tunnel dryer conveyer. This is

carried into the drying chamber by conveyer. At this stage the moisture content will

be less than 1% and organic additives are sprayed at the discharge of the conveyer.

This is now conveyed through bucket elevator and screw conveyer and stored in feed

bin.

Micronisation and Condensate Cooling

Dried pigment is micronized in the Micronisation section. This is to reduce the

particle size to 0.28 microns. Superheated steam is used as the grinding medium.

Macroni from the feed bin is fed to screw feeder, which feeds macroni into microniser

at an adjusted rate. The pigment is injected into the microniser chamber by a high

pressure steam ejector. Superheated steam which passes through the nozzles of the

microniser attains supersonic velocity. At this velocity pigment particles collide with

each other and particle size get reduced. The steam escapes to a condenser or scrubber

and micronized pigment particles are cooled and conveyed by low pressure air to a

secondary cyclone and from there to product bin. The steam and non-condensable

gases are drawn away through a fine scrubber and venturi scrubber by a vacuum

pump to atmosphere. The slurry flows to surge tank from where it is recycled back by

pumping through a heat exchanger.

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Product bagging

The hot micronized product is cooled conveyed by low pressure air. The finished

pigment product is bagged in paper bags and stored in the pigment storage building.

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DIFFERENT GRADES OF TiO2 PIGMENT

At present, KMML produces 7 grades of rutile grade TiO2 pigments

KEMOX RC 800

KEMOX RC 800 is low oil absorption, medium durable, and alumina treated Rutile

pigment produced by chloride process. It has high gloss producing properties for

interior trade sales paint and industrial coatings. It exhibits high brightness and

excellent tint strength in gloss and semi-gloss enamels.It is recommended for printing

inks, high gloss coating, industrial coatings, low abrasivity coatings, pigment for

letterpress gravure, polyamide etc. and exterior applications where maximum chalk

resistance is not required.

KEMOX RC 800 PG

KEMOX RC 800 PG is a low oil absorption, medium durable, alumina treated and

plastic grade rutile pigment produced by chloride process. It has high tint strength and

excellent dispersion property. It exhibits comparatively low abrasivity. It finds

application in plates requiring a blue white high dispersion TiO2. Other areas of

application are powder coatings, polyethylene films and vinyl sheet goods. It is used

in most other common plastic applications.

KEMOX RC 822

KEMOX RC 822 is an excellent pigment for paints, exterior and interior applications

in residential and architectural finishing, plastics, paper and printing inks.

KEMOX RC 804

KEMOX RC 804 is used for brilliant white color plastics or color concentrates

KEMOX RC 802

KEMOX RC 802 is a multipurpose superior performance rutile TiO2 pigment

manufactured by chloride process. It has been surface treated with alumina and silica.

KEMOX RC 802 has good capacity and weathering property. It has good gloss and is

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easily dispersible. It is intended for both exterior and interior applications. This is

recommended for architectural and industrial paints - both solvent and water based.

KEMOX RC 813

KEMOX RC 813 is a solvent based pigment.

KEMOX RC 808

KEMOX RC 808 is a universal grade pigment suitable for multiple uses especially for

automotive.

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UTILITIES

Utility department have the following sections:

1. Boiler plant

2. Water treatment plant

3. Air compressor station

4. Effluent pumping station

5. Furnace oil receipt storage & transferring section

6. Brick making plan

1. Boiler Plant

The boiler house is equipped with two water tube boilers and one fire tube boiler for

supplying steam to production plant

Water tube boiler (K463 and K 464)

Make : ISGEC JOHN CULCUTTA

Fuel : Furnace oil

Rating : 33T/hr.

Working pressure : 24Kg/cm2

Total heating surface : 1727M2

The boiler is steel cased, thin wall two-drum integral type water tube boiler with

natural circulation and balanced draft. The exit Flue gas from boiler passes through

economizer and outlet gases into atmospheres through chimney by means of ID fans.

After de- aeration the feed water is supplied to the steam drum through economizer

using multistage feed pump. The economizer is of through integral bare type parallel

tubes for picks up the heat from the flue gas. Water in the steam drum is circulated to

the mud drum via main bank tubes, from the mud drum it is distributed to evaporator

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main bank tubes and rest to the combustion chamber wall type via feeder pipes and

manifold.

A steam /water mixture is returned by natural circulation to the steam drum. This is

fitted with internal baffles and cyclone separators for separating steam water mixture

then the steam is purified by passing through scrubber box mounted on the top of the

cyclone. From the steam drum, saturated steam is conveyed to saturate collecting

header and distributed to the production plants via common distribution header.

Part of the steam from the steam drum goes to super heater. The superheated coils are

suspended in the horizontal draught between combustion chamber and the heat

recovery surfaces. There are 15 coils and finally collected in super-heated collecting

header and distributed to U-400 via common distribution header.

A)

B) Fire tube boiler (K 462)

Type : Horizontal smoke tube, 3 pass

Make : M/s Wester Works Limited, Bombay

Evaporation rate : 9T/Hr.

Max Working pressure : 19Kg/cm 2g

Fuel : Furnace oil

2. Water treatment plant

The sour water is Tube wells; and there are 7 tube wells with a draw capacity

100m3/hr. each. The plant has been designed to produce 560 m3/hr. filtered water.

Process of treatment is aeration, flocculation, clarification and filtration.

Aeration of raw water to convert iron from dissolved ferrous state to insoluble ferric

state. The aerated water after lime addition flows into a chute and then enters into

radial flow clarifier for flocculation and subsequent clarification. The effluent from

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the clarifier flows to the rapid gravity filters for filtration. The filtered water is

collected in a concrete reservoir. Filtered water is drawn from the filtered water

storage tank with the help of centrifugal pumps and supplying to different plants,

overhead tank and DM unit.

Five cooling water pumps are used supplying to circulate cooling water and 2 cooling

towers are provided for cooling the hot water. The hot water coming from various

plants sent through the vertical cross flow cooling tower cells and cooled water is

collected in the cold sump.

There is also a demineralization plant to produce DM water; it is used in U400, U300

and boiler plant. The DM water plant consists of 3 strong acid cation exchangers, 3

strong base anion exchangers, degasser tank, degasser pumps, degasser blower, DM

water pumps, DM water tank, and acid and alkali storage tanks with connected pipe

lines.

There is a fire and drinking water supply network in the factory. The whole plants are

connected with fire and drinking water line to meet the sanitary requirements as well

as for drinking purpose and firefighting. The fire and drinking water supply and

emergency water to U-300& DG is provided from the overhead tank.

As a part of welfare activities, KMML is supplying drinking water to local people

around KMML through 27 lines and 60 km length pipeline from my drinking water

lines. The duration of water supply to locals is 3 Hrs. per day. This network

supplying about 500m3 water to more than 10,000 beneficiaries.

3. Air compressor station

Operating of air compressors, driers and supply wet air and dry air to various plants

as per their requirements. There are 5 KG Khosala, two stage twin cylinder double

acting compressors each 45.44 NM3/Min capacity, 3 air receivers, 3 air driers each 75

NM3/Min Capacity at a pressure of 10Kg/cm2 and connected interplant piping.

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4. Effluent pumping station

This is for pumping of treated effluent in the polishing pond to sea. Pumping of

Effluents from various plants after neutralization is collected in settling pond and after

settling, the effluent water is collected in the polishing pond by overflow. There is a

Galigher pump with 280m3/hr. capacity and connected pipelines for about 1.5 km.

This is pumped out to sea if pH value is in the range 5.5 to 9. All statutory rules and

regulations are maintained while doing the operation.

As the old effluent pond was almost filled, from 2008 august they had switched over

to the old system to the new effluent ETP sludge pond. There are two vertical

Galigher pump having capacity of 100M3/hr. each and the discharge connected to the

old sea pumping line.

Also from December- 2009 they have commissioned supernatant water from treated

effluent neutralization system and about 50M3/hr. water is consuming from this water

for their process use in connection with the Zero discharge effluent system

5. Furnace oil receipt storage & transferring section

The main functions are receipt of Furnace Oil, handling, storage and delivery to the

user plants as per their request. They have two 1000KL capacity fuel oil tank, 3

transferring pump of 1000LPM capacity and two unloading pump with 340LPM

capacity each. After weighment and dip checking the oil tanker from central shores

will reach to furnace oil storage area and unloaded to oil tanks and final dip will be

taken and manage the stock. Operator in utility section will pump the furnace oil as

per the requirements of the various plants like IBP, ARP and Boiler.

6. Brick making plant

Iron oxide brick is the byproduct of KMML, using the raw materials are iron oxide

collected from iron oxide, waste sand from MS plant, waste silica sand from U300,

cement, lime and sodium silicate. They have two brick making plant with design

capacity 1200/hr. each. Contract persons with close supervision of utility department

carry out all operational functions. After curing these bricks are supplied for

construction purposes in KMML

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