The method of producing titanium dioxide

 

(57) Abstract:

The invention relates to the production of titanium dioxide by vapor-phase hydrolysis of titanium halide. The method of obtaining titanium dioxide includes obtaining gas mixture, the interaction of the mixture with pairs of titanium tetrachloride, an introduction to the process of vapor-phase hydrolysis of additives in the form of aluminium chloride and/or potassium chloride and silicon tetrachloride, and the Department of titanium dioxide from the reaction products. A pair of silicon tetrachloride is injected parallel to the movement of the vapor-gas mixture, and as an additive of silicon tetrachloride using waste from the distillation purification of titanium tetrachloride. The content of silicon tetrachloride in the waste from the distillation purification of titanium tetrachloride is 30-60 wt.%. Waste serves in the range of 0.1 to 1.0% in terms of silicon dioxide in the finished titanium dioxide. Before feeding into the reactor waste from the distillation purification of titanium tetrachloride is heated to a vapor state. The technical result of the invention improves the performance of the process vapor hydrolysis, to reduce the cost of purchasing raw materials, additives used in the process of hydrolysis. Use as an additive from the century 3 C.p. f-crystals.

The invention relates to the production of titanium dioxide by vapor-phase hydrolysis of titanium halide.

A method of obtaining titanium dioxide (CBL.UK application No. 1286760) in the vapor phase by burning a combustible gas to the burner when the tangential supply of oxygen. The resulting combustion products introduced into the reaction zone, which serves as a pair of titanium tetrachloride and water. The titanium tetrachloride can be added aluminum chloride and silicon tetrachloride.

The disadvantages of this method of obtaining titanium dioxide are significant costs of producing pure oxygen and complex instrumentation.

A method of obtaining titanium dioxide (U.S. Pat.U.S. No. 3467498, publ.16.09.1969), in which the Central tube serves oxygen, heated to the temperature T, the titanium tetrachloride is injected through coaxially disposed tube at speeds from 2.5 to 300 m/s at a temperature not exceeding 500 ° C, in the amount of 32 g mol/min. In a stream of titanium tetrachloride introduced a pair of aluminium chloride are heated to 300C. Here we introduce 0.18 g mol/min of liquid silicon tetrachloride.

The disadvantage of this method is that the lower ends of the tubes are formed deposits dioxide is tan (patent RU №2169119, publ. 20.06.2001,, BIPM No. 17), the number of General characteristics taken as the closest analogue is the prototype. The method of obtaining titanium dioxide involves feeding preheated to a temperature of 200-400C of titanium tetrachloride into the reactor, the combustion air natural gas, the supply of water in the combustion products to obtain a gas mixture. Gas-vapor mixture is fed into the reactor for vapor-phase hydrolysis perpendicular to the flow of vapors of titanium tetrachloride. The ratio of titanium tetrachloride : gas-vapor mixture is 1:2-4. At the same time in the reactor an additive of aluminum chloride at an angle of 50-55 to the movement of vapors of titanium tetrachloride, additive potassium chloride serves perpendicular to the movement of the gas mixture.

The disadvantage of this method is that the particles of titanium dioxide in the process of vapor-phase hydrolysis have a high surface activity, resulting acquire electric charges that cause mutual attraction of the particles, their adhesion and aggregation, it causes the sedimentation of aggregated particles of titanium dioxide on the inner side of the reactor, which significantly reduces the efficiency of the process increases the labor costs for cleaning of equipment, reduces the product yield.

The technical result is achieved in that a method of obtaining titanium dioxide, including the production of vapor-gas mixture, the interaction of the mixture with pairs of titanium tetrachloride, an introduction to the process of vapor-phase hydrolysis of additives in the form of aluminium chloride and/or potassium chloride, separating the titanium dioxide from the reaction products, what's new is that as an additive impose additional silicon tetrachloride parallel to the gas-vapor mixture in the form of waste from the distillation purification of titanium tetrachloride.

In addition, the content of silicon tetrachloride in the waste from the distillation purification of titanium tetrachloride is 30-60 wt.%.

In addition, the waste serves in the range of 0.1 to 1.0% in terms of silicon dioxide in the finished titanium dioxide.

In addition, before feeding into the reactor waste from the distillation purification of titanium tetrachloride is heated to vapor sostavljaet to handle particles of titanium dioxide compounds of silicon, to reduce adhesion of particles of titanium dioxide, to reduce their sedimentation on the inner surface of the reactor and thereby to improve the performance of the method.

Use as an additive silicon tetrachloride waste distillation purification of titanium tetrachloride can reduce the cost of purchasing expensive supplements.

Conducted by the applicant's analysis of the prior art, including searching by the patent and scientific and technical information sources, and identify sources that contain information about the equivalents of the claimed invention, has allowed to establish that the applicant had not found the source, which is characterized by signs, identical all the essential features of the invention. The definition from the list of identified unique prototype, as the most similar set of features analogue, has allowed to establish the essential towards perceived by the applicant to the technical result of the distinctive features in the claimed method of producing titanium dioxide set forth in the claims.

Therefore, the claimed invention meets the condition of “novelty.”

To check compliance with the s solutions to identify signs that match the distinctive features of the prototype of the characteristics of the claimed method. The search results showed that the claimed invention not apparent to the expert in the obvious way from the prior art because the prior art defined by the applicant, not the influence provided the essential features of the claimed invention transformations to achieve a technical result. Therefore, the claimed invention meets the condition of “inventive step”.

An example of the method.

Pre-purified titanium tetrachloride (TU 1715-455-05785388-99) served in the cube evaporator where it is evaporated at a temperature of 136-140 C, then the pair is served in the superheater, again heated to a temperature of 200-S and sent to the reactor for vapor-phase hydrolysis. In a separate furnace carry out the combustion of natural gas (GOST 5542-87) and compressed air (TU 05785388-009) at a temperature of 1100-1300C. In the furnace serves 50-300 kg/h of water while maintaining up to 20% above the stoichiometric amount required for the reaction of interaction with pairs of titanium tetrachloride. The combustion of 1 nm3natural gas spend 11-20 nm3air. Poluce m3/h and at a temperature of 800-1300C perpendicular to the flow of vapors of titanium tetrachloride into the reactor for vapor-phase hydrolysis, maintaining the ratio of titanium tetrachloride: vapor-gas mixture is equal to 1:(2-4). In the reactor a vapor-phase hydrolysis serves supplements in the form of vapors of aluminum chloride and/or potassium chloride and silicon tetrachloride. Aluminium chloride in solid form is heated in a separate tank to a vapor state and serves at an angle of 50-55 into the reactor at a speed of 2.5 to 5.0 kg/h Into the reactor for vapor-phase hydrolysis can be submitted simultaneously with the addition of potassium chloride, which serves perpendicular to the movement of the gas mixture. Silicon tetrachloride is a waste distillation purification tetrachloride titanium content of silicon tetrachloride 30-60%, heated in a separate tank to a vapor state and a pair of guide parallel to the movement of the vapor-gas mixture in the reactor. In the reactor at a temperature of 600-S pair of titanium tetrachloride interact with water by reactions

TiCl4(pairs)+2H2O(pairs)=TiO2(TV.)+4l+Q

Received palaeohistology mixture is sent to the camera pre-cooling, where it is cooled to a temperature of 400-800C. Then carry out subsequent processing of dust and gas smea periodically discharged into the container. Receiving waste distillation purification of titanium tetrachloride containing silicon tetrachloride. After cleaning from the technical vanadium tetrachloride titanium content, wt.% vanadium 0,15, chlorine 0,12, silicon 0,006, the phosgene acetylchloride 0,008, pumped into the tank, then in pressure vessels distillation columns. From pressure tanks served in the heater, where it is heated to a temperature of not less than S, and sent to the middle part of the distillation column. Cleaning from boiling impurities, namely from silicon tetrachloride with a boiling point S, phosgene, chlorine, hydrogen chloride, carbon dioxide is carried out in a Packed distillation columns or columns with disastrous lattice / tube sheet or plate with overflow devices. Pair boiling liquid from the upper part of the distillation column enter the condenser-reflux condenser, where it is condensation. Get distillate containing, wt.%: 22-30 - liquid titanium tetrachloride with the contents of the boiling impurities, such as SiCl445-66, 1,5 CCL4, 13 COCl2. On existing technology waste wash water and sent to the sewer. In the cleaning process gain 1-2 kg of distillate per 1 ton of titanium tetrachloride (see kN. Corsim way the proposed set of essential features of the invention improves the performance of the method of obtaining titanium dioxide, to reduce the cost of cleaning equipment and the purchase of expensive additives.

1. The method of obtaining titanium dioxide, including the production of vapor-gas mixture, the interaction of the mixture with pairs of titanium tetrachloride, an introduction to the process of vapor-phase hydrolysis of additives in the form of aluminium chloride and/or potassium chloride, separating the titanium dioxide from the reaction products, wherein the additive further added silicon tetrachloride parallel to the gas-vapor mixture in the form of waste from the distillation purification of titanium tetrachloride.

2. The method according to p. 1, characterized in that the content of silicon tetrachloride in the waste from the distillation purification of titanium tetrachloride is 30-60 wt.%.

3. The method according to p. 1, characterized in that the waste serves in the range of 0.1 to 1.0% in terms of silicon dioxide in the finished titanium dioxide.

4. The method according to p. 1, wherein the pre before it enters the reactor waste from the distillation purification of titanium tetrachloride is heated to a vapor state.

 

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