MANUFACTURE OF TITANIUM DIOXIDE

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MANUFACTURE OF TITANIUM DIOXIDE : 

MANUFACTURE OF TITANIUM DIOXIDE By JENITHA.A

TITANIUM DIOXIDE : 

TITANIUM DIOXIDE INTRODUCTION: Atomic Weight : 47.9 Atomic Number : 22 Discovered by “REVEREND WILLIAM GNEGOR” (England)

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PROPERTIES OF TITANIUM DIOXIDE: Titanium the first member of group IVA of the periodic table exhibits a valency of 4+ in its most stable compounds. Its molecular weight is 79.9. 100 gm of Titanium Dioxide contains 59.9 gm of Titanium and 40.05 gm of oxygen.

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Titanium Dioxide occurs naturally in three crystalline form’s naturally Anatase, Brookite and Rutile. These are substantially pure Titanium Dioxide but usually contains small amount of impurities like Iron Titanium Dioxide is extremely stable at high temperature .

MANUFACTURING STEPS : 

MANUFACTURING STEPS PROCESS ❶ PROCESS ❷ BALL MILL ROTARY CLASSIFIER DOUBLE CONE CLASSIFIER CYCLONE SEPARATOR DIGESTOR REDUCTION TANK CLARIFIER EFFLUENT TREATMENT HEAT EXCHANGER CONCENTRATOR HYDROLYSIS CALCINER PIGMENT MILL

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MAJOR RAW MATERIALS Ilmenite: The ilmenite ore also contains some amount of Sio2, Cr2o3, Al2o3, P2.o5, V2o5 Ilmenite contains 98% of Magnetic property

BALL MILL : 

BALL MILL PROCEDURE Feed ilmenite is transferred through bucket elevator and stored in the feed tank. The feed is allowed through constant feed conveyor in to RAL. Through RAL [Rotary Air Lock] ilmenites are fed in to the Ball Mill. RAL is used to keep the completed system in negative manner.

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Ball Mill consists of 40mm and 25mm balls. 40mm balls – 7000 kg 25 mm balls – 6200 kg While running the ball mill a gravitational force’s cuts the centrifugal action, which leads to the tumbling action. Thus the ilmenite grounded form 35 Mesh size to 325 Mesh size

ROTARY CLASSIFIER : 

ROTARY CLASSIFIER The grounded product is allowed to pass through the rotary drier. The courses particles are dropped out and are channeled back to the mill for regrinding

DOUBLE CONE CLASSIFIER : 

DOUBLE CONE CLASSIFIER The air with finer product rises up in to the double cone classifier where the oversize materials gets separated from the air stream and is returned to the mill by the inlet air duct

CYCLONE SEPARATOR : 

CYCLONE SEPARATOR The air leaving the double cone classifier contains only the required smaller size particles. They are allowed to enter into cyclone separator to remove the impurities.

DIGESTOR : 

DIGESTOR Check bottom drain valve and discharge valve. Ensure steam and compressed airs are available for digestor. Now small size ilmenite particles are allowed to enter into the digestor and H2SO4 acid is added inside the digestor . Now 325 gm of Glycerol Mono Styrene is added to avoid Vigorous reaction.

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Temperature should be maintained between 57o-60o. Now add water to the digestor to reduce sulphuric acid concentration from 98% to 88%. Exothermic reaction is taking place in the digestor. FeO.Fe2O3TiO2+5H2SO4→FeSO4+Fe2 (SO4)3+Ti OSO4 + 5 H2O All oxides are converted into sulphate. Thus the total cycle time in digestor is 8 hours 15 minutes.

REDUCTION TANK : 

REDUCTION TANK In this reduction tank,Ti2O3 Present implies that ferric ions from digestor is completely reduced to ferrous. Fe +H2SO4 → FeSO4 + 2(H) Fe2 (SO4)3 + 2(H) → 2FeSO4 + H2SO4 Finished Reduction batch should contain specific gravity around 1.560 and temperature between 70 to 75 degree celcius. 2TiO (SO4) + 2 H + H2SO4 → Ti2 (SO4)3 + H2O

CLARIFIER : 

CLARIFIER Pumping of crude liquor from storage tank to the clarifier. INFOC – VISCOUS SOLUTION. which is added to the liquor. Now the waste sludge particles are settle down because infloc plays the major role to bring down the unreacted sludge particles Infloc – 2.7kg / 2.5m3 Flow rate – 700 ml / 5 sec

FILTERATION : 

FILTERATION Now the overflow from the clarifier is allowed to pass through the filter press. The unwanted materials are removed. Filtered liquor return back and stored in storage tank.

EFFLUENT TREATMENT : 

EFFLUENT TREATMENT The raw materials for the process are the waste liquor from the post precipitation filters. It contains free H2SO4, FeSO4 etc.

HEAT EXCHANGER : 

HEAT EXCHANGER The filtered liquor from process ❶ is pumped and stored in temperature regulating tank(50 -55 degree Celsius) The Fe content is 0.80-0.85 This liquor is allowed to enter into the heat exchanger which is made of copper tubes.

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The liquor flows through the tube and the water flows through the shell. The heat exchanger may contain around 260 tubes. Now the temperature is reduce to 30-32oc.

CONCENTRATER : 

CONCENTRATER Concentrator contains 22 tubes. The temperature of the liquor gets raised to 70oc by using preheaters. Now the liquor is concentrated. And the liquor and vapor gets separator, thus this vapor is used in preheated.

HYDROLYSIS : 

HYDROLYSIS The process that takes place here is hydrolysis. TioSO4+ 2H2O → TiO(OH)2 + H2SO4 The ratio between the acid and titanium plays a major role The particles size will be fine and the setting rate get decreases. During hydrolysis the sulphate of titanium undergoes precipitation results in hydrated titanium. .

CALCINER : 

CALCINER SPECIFICATION Length - 44 m Outer dia. - 2.65 m Inner dia. - 2.5 m Atomizing air pressure - 3 kg/cm2 Fuel oil pressure - 1.8 kg/cm2 Combustion air pressure - 100 mm/w Dilution air pressure - 5 mm/w

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The temperature of the kiln in the centre portion will be 900 degree Celsius. It is layered with fire bricks. There are three zones Pre heating Desulphonation Crystal formation zone.

PIGMENT MILL : 

PIGMENT MILL The final product from the calciner is allowed for grinding in the pigment mill. This will give us the required particle size of Titanium Dioxide.

APPLICATION OF TITANIUM DIOXIDE : 

APPLICATION OF TITANIUM DIOXIDE The main use of titanium dioxide (TiO2) is as a white powder pigment because of its brightness and very high refractive index. This means that relatively low levels of the pigment are required to achieve a white opaque coating. One of the major advantages for titanium dioxide is its resistance to discoloration under ultraviolet (UV) light in exposed applications.

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It is used in products such as paints and coatings, including glazes and enamels, plastics, paper, inks, fibers, foods, pharmaceuticals and cosmetics. In particular, high performance grades of TiO2 are finding a growing market in the cosmetics sector and most toothpastes use TiO2. Its UV light resistance properties helps prevent the discoloration of plastics in sunlight. Sunscreens also use TiO2 as a blocker because of its high refractive index and the ability to protect the skin from UV light. Titanium dioxide is seeing growing demand in photo catalysts due to its oxidative and hydrolysis properties

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THANK YOU