Method for producing titanium dioxide by low-temperature chlorination of titanium-rich material

文档序号:657219 发布日期:2021-04-27 浏览:23次 中文

阅读说明:本技术 一种富钛料低温氯化生产二氧化钛的方法 (Method for producing titanium dioxide by low-temperature chlorination of titanium-rich material ) 是由 范川林 朱庆山 杨海涛 马素刚 李洪钟 于 2019-10-25 设计创作,主要内容包括:本发明属于化工、冶金领域。具体地,本发明公开了一种富钛料低温氯化生产二氧化钛的方法。本方法通过富钛料配加碳粉、粘结剂破碎磨细、混合压块强化矿/碳接触效果,降低氯化反应温度;通过将氯化反应器中的高温物料循环排出,采用氮气冷却降温后返回氯化炉,实现氯化反应器热量的高效移出;通过采用换热得到的热氮气为热固化工序提供热量,提高能源利用效率,降低能源消耗;通过对四氯化钛氧化产生的含氧氯气脱氧冷却处理,降低氯化反应器的氧气引入量,解决低温氯化反应器温度波动的问题;从而实现富钛料短流程高效利用的难题。本方法具有原料适应性广,资源利用率高,节能降耗,环境友好等优点。(The invention belongs to the field of chemical industry and metallurgy. Specifically, the invention discloses a method for producing titanium dioxide by low-temperature chlorination of a titanium-rich material. The method enhances the ore/carbon contact effect by adding carbon powder and binder into the titanium-rich material, crushing and grinding the titanium-rich material, mixing and briquetting the titanium-rich material and reducing the chlorination reaction temperature; high-temperature materials in the chlorination reactor are discharged in a circulating manner, and are cooled by nitrogen and then returned to the chlorination furnace, so that the heat of the chlorination reactor is efficiently removed; the hot nitrogen obtained by heat exchange is adopted to provide heat for the thermocuring process, so that the energy utilization efficiency is improved, and the energy consumption is reduced; the oxygen-containing chlorine generated by oxidizing titanium tetrachloride is deoxidized and cooled, so that the oxygen introduction amount of a chlorination reactor is reduced, and the problem of temperature fluctuation of a low-temperature chlorination reactor is solved; thereby realizing the difficult problem of short-flow high-efficiency utilization of the titanium-rich material. The method has the advantages of wide raw material adaptability, high resource utilization rate, energy conservation, consumption reduction, environmental friendliness and the like.)

1. The method for producing titanium dioxide by low-temperature chlorination of a titanium-rich material comprises a crushing and grinding process (1), a mixed briquetting process (2), a thermosetting process (3), a crushing and screening process (4), a low-temperature chlorination process (5), a cooling and heat exchange process (6), a refining process (7), a high-temperature oxidation process (8) and a deoxidation and cooling process (9), and comprises the following steps:

1) in the crushing and grinding process (1), the titanium-rich material is added with carbon powder and a binder to be crushed and ground to obtain fine mineral powder;

2) in the mixed briquetting process (2), fine mineral powder and fine powder from the crushing and screening process (4) are uniformly mixed and pressed into briquettes;

3) in the heat curing process (3), the pressed block exchanges heat with hot nitrogen from the cooling heat exchange process (6) to realize heat curing to obtain a cured material;

4) in the crushing and screening process (4), the solidified materials are crushed and screened to obtain chlorinated raw materials and fine powder meeting the particle size requirement of the fluidized chlorination reaction, and the fine powder returns to the mixing and briquetting process (2) for recycling;

5) in the low-temperature chlorination procedure (5), the chlorination raw material reacts with chlorine and circulating chlorine to obtain crude titanium tetrachloride and chlorination slag, and the chlorination slag is sent to environment-friendly treatment;

6) in the cooling heat exchange step (6), the hot material from the low-temperature chlorination step (5) exchanges heat with nitrogen to obtain cold material and hot nitrogen, the cold material returns to the low-temperature chlorination step (5), and the hot nitrogen is sent to the hot curing step (3);

7) in the refining step (7), the crude titanium tetrachloride is refined to obtain refined titanium tetrachloride;

8) in the high-temperature oxidation process (8), the fine titanium tetrachloride reacts with oxygen at high temperature to obtain titanium dioxide and oxygen-containing chlorine;

9) in the deoxidation cooling process (7), oxygen-containing chlorine gas is deoxidized under the action of a deoxidizer, and is cooled to obtain circulating chlorine gas, and the circulating chlorine gas is returned to the low-temperature chlorination process (5) to be used as a chlorinating agent.

2. The method for producing titanium dioxide by low-temperature chlorination of titanium-rich material as claimed in claim 1, wherein the TiO in the titanium-rich material2The mass percentage content is 40-98%, the titanium-rich material includes but is not limited to vanadium-titanium magnetite concentrate direct reduction melting titanium slag, high calcium-magnesium acid soluble titanium slag, high titanium slag, natural rutile, artificial rutile and waste denitration catalystOne or more of (a).

3. The method for producing titanium dioxide by low-temperature chlorination of the titanium-rich material according to claim 1, wherein in the crushing and grinding step (1), the carbon powder is one or more of activated carbon, metallurgical coke, petroleum coke and coal powder, and the binder is one or more of phenolic resin, sucrose, starch, asphalt and polyvinyl alcohol.

4. The method for producing titanium dioxide by low-temperature chlorination of titanium-rich material according to claim 1, wherein in the crushing and grinding step (1), carbon powder and binder are added to the titanium-rich material, the mass of the added carbon powder is 10-50% of the mass of the titanium-rich material, and the mass of the added binder is 1-10% of the mass of the titanium-rich material.

5. The method for producing titanium dioxide by low-temperature chlorination of titanium-rich material as claimed in claim 1, wherein in the crushing and grinding step (1), the average particle size of the ground mixed fine ore powder is controlled to be less than 50 μm.

6. The method for producing titanium dioxide by low-temperature chlorination of titanium-rich material according to claim 1, wherein in the mixed briquetting process (2), the fine ore powder is formed by pressing, and the pressure in the mixed briquetting process (2) is 0.3MPa-20 MPa.

7. The method for producing titanium dioxide by low-temperature chlorination of titanium-rich material according to claim 1, wherein in the heat curing step (3), the temperature of hot nitrogen is 400-680 ℃, and the curing temperature is 100-650 ℃.

8. The method for producing titanium dioxide by low-temperature chlorination of titanium-rich material according to claim 1, wherein in the crushing and screening step (4), the average screening particle size of the chlorinated raw material is controlled to be 60 μm-300 μm.

9. The method for producing titanium dioxide by low-temperature chlorination of titanium-rich materials according to claim 1, wherein in the low-temperature chlorination step (5), the reactor is a gas-solid fluidized bed, the chlorination temperature is 400-680 ℃, and the average residence time is 30-240 min.

10. The method for producing titanium dioxide by low-temperature chlorination of the titanium-rich material according to claim 1, wherein in the cooling heat exchange step (6), the hot material from the low-temperature chlorination step (5) is cooled to 200-350 ℃ through heat exchange with nitrogen, the cooled material is returned to the low-temperature chlorination step (5), and the circulation amount of the material per unit time is 1-15 times of the treatment amount of the titanium-rich material per unit time.

11. The method for producing titanium dioxide by low-temperature chlorination of the titanium-rich material according to claim 1, wherein in the deoxidation cooling process (9), the deoxidizer is one or more of activated carbon, metallurgical coke, petroleum coke, coal powder and carbon monoxide, the deoxidation temperature is 400-800 ℃, the average residence time is 30-90 min, and the chlorine after deoxidation is cooled to below 200 ℃, and the chlorine returns to the low-temperature chlorination process.

Technical Field

The invention belongs to the fields of chemical industry and metallurgy, and particularly relates to a method for producing titanium dioxide by low-temperature chlorination of a titanium-rich material.

Background

At present, the utilization paths of titanium resources mainly comprise two processes, namely a chlorination process and a sulfuric acid process, wherein the chlorination process comprises fluidization chlorination and molten salt chlorination. The fluidized chlorination refers to the process of carbon-matching chlorination of titanium-containing materials in a fluidized bed to obtain titanium tetrachloride intermediate products. Titanium tetrachloride can be oxidized to produce titanium dioxide, and also can be reduced by magnesium to produce titanium sponge. The fluidization chlorination process has short flow, low cost, little pollution and high capacity, and is a mainstream advanced titanium resource utilization technology. But the fluidization chlorination process has high requirements on raw materials, the grade of the titanium dioxide is over 90 percent, and the particle size is over 90 percent in the range of 75-300 mu m. The operating temperature of the fluidization chlorination process is generally 800-1000 ℃, and at the temperature, impurities such as CaO, MgO and the like in the raw materials can be chlorinated to generate molten CaCl2And MgCl2Binding the material and disrupting normal fluidization. Therefore, the CaO content of the chlorinated raw material is generally required to be less than 0.3%, and the MgO content is required to be less than 1.2%. The molten salt chlorination refers to the process of adding carbon into a titanium-containing material in molten salt mainly comprising sodium chloride and potassium chloride for chlorination to produce a titanium tetrachloride intermediate product, and further produce titanium dioxide or titanium sponge. The molten salt chlorination has the problems of large waste salt amount, low productivity and low efficiency, and greatly limits the application range of the method. The sulfuric acid process is to dissolve titanium-containing material in sulfuric acid system to obtain titanyl sulfate and produce titanium white powder through hydrolysis. The sulfuric acid process is usually carried out on titanium concentrates (TiO)2Grade about 50%) or acid-soluble titanium slag (TiO)2The grade is about 70 percent) is used as raw materials, the energy consumption in the production process is high, the pollution is large, and the technology is eliminated internationally.

China is a large titanium resource country, the mineral reserve accounts for more than 35% of the world, and the mineral reserve mainly exists in the form of vanadium titano-magnetite. At present, the titanium resource utilization path in China is as follows, and vanadium titano-magnetite raw ore is subjected to mineral separation to obtain iron concentrate and titanium concentrate (containing TiO)2Grade 50% or so). Smelting the titanium concentrate in an electric furnace to obtain acid-soluble titanium slag containing TiO2About 70%, CaO about 2%, and MgO about 8%. Because of low titanium grade and high content of impurities such as calcium, magnesium and the like, the titanium is difficult to be used as a raw material of a fluidization chlorination process. In addition, in the conventional fluidized chlorination process, a large amount of fine titanium-rich material is generated in order to control the particle size of the raw material, and cannot be utilized. In order to solve the problem of utilization of high-calcium-magnesium titanium-containing materials and fine-grain titanium-rich materials, researchers explore new technological processes of optimizing the structure of a reactor, upgrading titanium slag, reducing reaction temperature and the like. Chinese patent CN1454849B discloses a device and a method for preparing titanium tetrachloride by chlorination of titanium-containing minerals. The method designs a plurality of fluidized bed reactors, so that gas-solid reaction is respectively carried out in a fast bed, a turbulent bed and an ascending bed, thereby solving the problem of adhesive flow loss. However, this method increases the number of reactors, increases the operation speed, leads to an increase in the system pressure, and increases the operation complexity. The invention patent US5830420 discloses a method for upgrading titanium slag, which is characterized in that the upgraded titanium slag product is obtained by the procedures of oxidizing roasting, reducing roasting, acid leaching, alkaline leaching and calcining the titanium slag. Although the process can improve the grade of the titanium slag, three sections of high-temperature calcination are needed, and the processing cost is greatly improved. In addition, impurities such as calcium, magnesium, aluminum, silicon iron and the like in the titanium slag enter acidic or alkaline solution in the acid leaching or alkaline leaching process, and a large amount of waste water is generated by treating the waste liquid, so that the environmental pollution cost is increased. The Chinese patent application CN104176775A discloses a preparation method of a titanium-rich material. The method mainly comprises the following steps: acid-soluble titanium slag is added with sodium hydroxide or sodium carbonate to be modified and roasted at 900-1000 ℃, and then TiO is obtained by acid leaching at two ends2The grade of the titanium-rich material is more than 90 percent. However, in the acid leaching process, there is a problem of easy pulverization of the particles, and although the grade is raised, it is still difficult to use as a raw material for the fluidized chlorination process. The Chinese invention patent application CN109399706A discloses a method for upgrading UGS slag by high-calcium magnesium titanium slag. The medium-high calcium magnesium titanium slag is subjected to alkali leaching, oxidizing roasting, reducing sodium salt roasting, pressurized acid leaching, roasting and other steps to obtain TiO2The grade of the titanium-rich material is more than 93 percent, and the total content of calcium and magnesium is within 1.5 percent. The invention also has the problems of long flow, high energy consumption and product pulverization.

The reduction of the chlorination reaction temperature is an important technical route for realizing the utilization of the high-calcium-magnesium titanium-rich material. Chinese patent application CN109052461A discloses a high-capacity molten salt chlorination device for treating high-calcium magnesium titanium slag and a production method thereof. The method is characterized in that high-calcium magnesium acid soluble titanium slag is used as a raw material in sodium chloride-based molten salt, and titanium tetrachloride is produced by carbon-assisted chlorination at the reaction temperature of 700-800 ℃. However, the process generates a large amount of waste salt containing sodium, calcium and magnesium, which is difficult to treat. Meanwhile, the fused salt chlorination has the problems of low productivity and low efficiency. The Chinese invention patent CN101164895B discloses a method for producing titanium tetrachloride by low-temperature chlorination. The method adopts a moving bed reactor or a fluidized bed reactor, and adopts chlorohydrocarbon and a titanium-containing raw material to perform a carbon chlorination reaction to produce the titanium tetrachloride under the condition that the temperature is lower than the melting point of calcium-magnesium chloride under the synergistic action of oxidizing gas. The chlorination temperature is 400-600 ℃, and the adopted chlorinated hydrocarbon is carbon tetrachloride, dichloromethane, chloroform and the like. The chlorinated hydrocarbon in the process is expensive, and the regeneration cycle cost is high, so that the process is difficult to be applied in large scale in production. US patent 2761760 discloses a process for producing titanium tetrachloride. The invention adopts titanium-rich material with less than 100 meshes, fine carbon powder and adhesive for pelletizing, takes NOCl with high reaction activity as a chlorinating agent, adopts a fixed bed reactor, and can reduce the chlorination temperature to 400 ℃. In the process, the chlorinating agent NOCl is expensive, the recycling and regenerating cost is high, the reaction efficiency of the fixed bed is low, and the large-scale application in production is difficult. The invention patent US4310495 discloses a low-temperature chlorination process of titanium-rich materials. The invention takes microporous carbon as a reducing agent, and the chlorination temperature is 600-800 ℃. The microporous carbon is obtained by controlling and oxidizing coal at 400 ℃, and the aperture of the microporous carbon is required to be less than 2 nm. The invention adopts the microporous carbon with high activity as a reducing agent, has strict requirements on the aperture and is difficult to be applied in large scale in production. The Chinese patent application CN107324336A discloses a method for preparing titanium carbide from acid-soluble titanium slag, which comprises adding a reducing agent into the acid-soluble titanium slag for pelletizing, and carbonizing at 1600-1650 ℃. Chinese patent CN101418383B discloses a method for preparing TiCl from titanium-containing slag4The method of (1). The invention uses titanium carbide slag in a low temperature region 30Low-temperature chlorination at the temperature of 0-650 ℃. The low-temperature chlorination of titanium carbide can greatly reduce the chlorination of calcium and magnesium, and the reaction temperature is lower than the melting temperature of calcium and magnesium chloride, so that the problem of bonding and fluid loss is solved. By combining the two inventions, the process for producing the titanium dioxide by carrying out high-temperature carbonization and low-temperature chlorination on the acid-soluble titanium slag can solve the problem of utilization of the high-calcium magnesium titanium slag. However, in practice, high-grade titanium carbide emits a large amount of heat in the low-temperature chlorination process, and the heat transfer problem of the reactor is difficult to solve. Meanwhile, the circulating chlorine generated in the titanium tetrachloride oxidation process contains part of unreacted oxygen, and the oxygen in the part of circulating chlorine enters the chlorination reactor and reacts with carbon to cause the temperature of the reactor to rise, so that the temperature control difficulty of the low-temperature chlorination reactor is aggravated.

The reaction temperature can be effectively reduced by reducing the particle size of the reaction materials, strengthening the ore/carbon contact effect and then controlling the proper particle size through pre-condensation. US patent 2936217 discloses a method for chlorinating titanium-rich materials. The invention requires that the proportion of the titanium-rich material with the grain diameter below 200 meshes is more than 80 percent, and the proportion of the carbonaceous reducing agent with the grain diameter below 140 meshes is more than 80 percent. Adding carbonaceous reducing agent and inorganic binder (SiO) into the titanium-rich material2/Na2O) granulating, and controlling the grain diameter between 200 meshes and 8 meshes. Adopting a fluidized bed reactor, wherein the reaction temperature is 700-950 ℃. The invention adopts the sodium-containing binder, and has the problem of binder loss in the fluidized chlorination process. And the chlorination temperature is above 700 ℃, so that the titanium-rich material containing calcium and magnesium still cannot be treated. US patent 4187117 discloses a titanium slag-coke pre-agglomerated particle for fluidized bed chlorination. Controlling the particle size of titanium slag and asphalt below 325 meshes, adding a binder, granulating by a disc granulator, controlling the granularity of the granules to be between 28 meshes and 100 meshes, carrying out heat curing at 920-940 ℃, and carrying out chlorination reaction at 690-740 ℃. The invention has higher thermal curing temperature and brings higher energy consumption. And the chlorination temperature is above 690 ℃, so that the titanium-rich material with high calcium and magnesium can not be treated. Chinese patent application CN1957097A discloses a method for agglomerating titanium dioxide. Mixing titanium-rich material with average particle size less than 106 μm with organic binder, granulating, and controlling average particle size of polymer particles to 106 μm E1000 μm. In polymer particles (TiO)2And the FeO)/C mass ratio is greater than 3.4. The polymeric particles are chlorinated with chlorine in a fluidized bed reactor to obtain titanium tetrachloride. The chlorination reaction temperature is 900-1200 ℃. The invention mainly discloses a method for pre-condensing a fine-grain titanium-rich material, but still adopts a high-temperature chlorination process route. The process is not suitable for high-calcium-magnesium titanium-rich material resources. Yang Fenglin and the like at the university of Buffalo, New York State university develop research on strengthening ore/carbon contact and realizing low-temperature chlorination of titanium-rich materials. Rutile with the average particle size of less than 5 mu m and carbon black with the average particle size of about 14nm are uniformly mixed, n-butanol is used as a binder, the mixture is pressed into tablets, the tablets are thermally cured at 800 ℃, then the tablets are crushed and screened to obtain the granules with the particle size (44 mu m-150 mu m) suitable for fluidization, and the chlorination reaction temperature is 350-450 ℃. Meanwhile, Yang Fenglin and the like research the low-temperature chlorination of the titanium sulfate white waste, and the content of titanium dioxide in the waste is about 50%. Mixing and grinding titanium white waste, carbon powder and water, filtering, pressing into tablets, crushing and screening to obtain particles with particle size of 250-420 μm suitable for fluidization, wherein the chlorination reaction temperature is 350-450 ℃. Research on lowering the chlorination reaction temperature by enhancing ore/carbon contact has been ongoing for more than half a century and has not been applied to industry on a large scale to date. The main reasons are as follows: (1) in order to ensure the strength of the pre-coagulation body, a binder is generally added and is subjected to heat curing, so that the energy consumption is large, and the production cost is increased. (2) The titanium-rich material is subjected to chlorination reaction at low temperature, and the product of the carbonaceous reducing agent is mainly CO2The heat release is significantly increased, making effective control of the furnace temperature difficult. (3) Meanwhile, the circulating chlorine generally contains unreacted oxygen, and the unreacted oxygen enters the chlorination reactor and reacts with carbon, so that the temperature rise of the chlorination reactor is further aggravated.

In conclusion, the existing high-calcium-magnesium titanium-rich material has the problems of long process, high energy consumption and low added value. Therefore, the invention develops a new process flow through technological innovation.

Disclosure of Invention

Aiming at the problems, the invention provides a method for producing titanium dioxide by low-temperature chlorination of a titanium-rich material. The method for producing titanium dioxide by low-temperature chlorination of the titanium-rich material provided by the invention has the advantages that the utilization efficiency of titanium is obviously improved, the process flow is greatly shortened, the added value of products is improved, the environmental pollution is reduced, and the method has obvious economic benefits and social benefits.

In order to achieve the purpose, the invention adopts the following technical scheme:

a method for producing titanium dioxide by low-temperature chlorination of a titanium-rich material comprises a crushing and grinding process 1, a mixed briquetting process 2, a thermosetting process 3, a crushing and screening process 4, a low-temperature chlorination process 5, a cooling and heat exchange process 6, a refining process 7, a high-temperature oxidation process 8 and a deoxidation and cooling process 9, and the method comprises the following steps:

1) in the crushing and grinding process 1, the titanium-rich material is added with carbon powder and a binder to be crushed and ground to obtain fine mineral powder;

2) in the mixed briquetting process 2, fine mineral powder and the fine powder from the crushing and screening process 4 are uniformly mixed and pressed into briquettes;

3) in the heat curing process 3, the pressed block exchanges heat with hot nitrogen from the cooling heat exchange process 6 to realize heat curing to obtain a cured material;

4) in the crushing and screening process 4, the solidified material is crushed and screened to obtain a chlorination raw material and fine powder meeting the particle size requirement of the fluidization chlorination reaction, and the fine powder returns to the mixing and briquetting process 2 for recycling;

5) in the low-temperature chlorination step 5, the chlorination raw material reacts with chlorine and circulating chlorine to obtain crude titanium tetrachloride and chlorination slag, and the chlorination slag is subjected to environment-friendly treatment;

6) in the cooling heat exchange process 6, the hot material from the low-temperature chlorination process 5 exchanges heat with nitrogen to obtain cold material and hot nitrogen, the cold material returns to the low-temperature chlorination process 5, and the hot nitrogen is sent to the hot curing process 3;

7) in the refining step 7, the crude titanium tetrachloride is refined to obtain refined titanium tetrachloride;

8) in the high-temperature oxidation process 8, the fine titanium tetrachloride reacts with oxygen at high temperature to obtain titanium dioxide and oxygen-containing chlorine;

9) in the deoxidation cooling process 7, oxygen-containing chlorine gas is deoxidized under the action of a deoxidizer, and is cooled to obtain circulating chlorine gas, and the circulating chlorine gas is returned to the low-temperature chlorination process 5 to be used as a chlorinating agent.

Preferably, TiO in the titanium-rich material2The mass percentage content is 40-98%, including but not limited to one or more of vanadium-titanium magnetite concentrate direct reduction melt separation titanium slag, high calcium-magnesium acid soluble titanium slag, high titanium slag, natural rutile, artificial rutile and waste denitration catalyst.

Preferably, in the crushing and grinding step 1, the carbon powder refers to one or more of activated carbon, metallurgical coke, petroleum coke and coal powder, and the binder refers to one or more of phenolic resin, sucrose, starch, asphalt and polyvinyl alcohol.

Preferably, in the crushing and grinding step 1, carbon powder and a binder are added to the titanium-rich material, wherein the addition mass of the carbon powder is 10-50% of that of the titanium-rich material, and the addition mass of the binder is 1-10% of that of the titanium-rich material.

Preferably, in the crushing and grinding step 1, the average particle size of the ground mixed fine ore powder is controlled to be less than 50 μm.

Preferably, in the mixed briquetting step 2, the fine ore powder is formed by pressing, and the pressure in the mixed briquetting step 2 is 0.3MPa to 20 MPa.

Preferably, in the thermosetting step 3, the hot nitrogen temperature is 400 to 680 ℃, and the curing temperature is 100 to 650 ℃.

Preferably, in the crushing and screening step 4, the average sieving particle size of the chlorinated raw material is controlled to be 60 to 300 μm.

Preferably, in the low-temperature chlorination step 5, the reactor is a gas-solid fluidized bed, the chlorination temperature is 400-680 ℃, and the average residence time is 30-240 min.

Preferably, in the cooling heat exchange step 6, the hot material from the low-temperature chlorination step 5 is cooled to 200-350 ℃ through heat exchange with nitrogen, the cooled material is returned to the low-temperature chlorination step 5, and the circulation amount of the material in unit time is 1-15 times of the treatment amount of the titanium-rich material in unit time.

Preferably, in the deoxidation cooling process 9, the deoxidizer is one or more of activated carbon, metallurgical coke, petroleum coke, coal powder and carbon monoxide, the deoxidation temperature is 400-800 ℃, the average residence time is 30-90 min, the chlorine after deoxidation is cooled to below 200 ℃, and the chlorine returns to the low-temperature chlorination process.

Compared with the prior art, the invention has the following outstanding advantages:

(1) the invention has wide raw material adaptability, and can be suitable for titanium-rich materials such as vanadium-titanium magnetite concentrate direct reduction melt separation titanium slag, high calcium-magnesium acid soluble titanium slag, high titanium slag, natural rutile, artificial rutile, waste denitration catalysts and the like.

(2) The titanium-rich material is granulated by mixing carbon powder, so that the ore/carbon contact effect is enhanced, the chlorination reaction temperature is reduced, the problem of loss of current caused by calcium and magnesium in high-temperature chlorination is avoided, and the method has important strategic significance for solving the problem of high calcium, magnesium and titanium resources in Shanxi.

(3) According to the invention, high-temperature materials in the chlorination reactor are discharged in a circulating manner, and the high-temperature materials are cooled by nitrogen and then returned to the chlorination furnace, so that the heat of the chlorination reactor is efficiently removed.

(4) According to the invention, hot nitrogen obtained by heat exchange is adopted to provide heat for the thermocuring process, so that the energy utilization efficiency is improved, and the energy consumption is reduced.

(5) The invention adopts the deoxidizer to remove the oxygen in the regenerated chlorine, thereby improving the heat stability in the low-temperature chlorination process.

(6) The invention realizes the low-temperature chlorination of the titanium-rich material, obviously improves the utilization efficiency of titanium, has simple flow and is convenient for production management and large-scale popularization and application.

According to the invention, the titanium-rich material is added with carbon powder, the binder is crushed and ground, and the mixed briquettes are used for enhancing the ore/carbon contact effect and reducing the chlorination reaction temperature; high-temperature materials in the chlorination reactor are discharged in a circulating manner, and are cooled by nitrogen and then returned to the chlorination furnace, so that the heat of the chlorination reactor is efficiently removed; the hot nitrogen obtained by heat exchange is adopted to provide heat for the thermocuring process, so that the energy utilization efficiency is improved, and the energy consumption is reduced; the oxygen-containing chlorine generated by oxidizing titanium tetrachloride is deoxidized, so that the oxygen introduction amount of a chlorination reactor is reduced, and the problem of temperature fluctuation of a low-temperature chlorination reactor is solved; thereby realizing the difficult problem of short-flow high-efficiency utilization of the titanium-rich material. The method for producing titanium dioxide by low-temperature chlorination of titanium-rich materials provided by the invention has important significance for improving the high-efficiency utilization of titanium resources in China.

Drawings

The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and together with the description serve to explain the principles of the invention and not to limit the invention.

FIG. 1 is a schematic flow chart of a method for producing titanium dioxide by low-temperature chlorination of a titanium-rich material.

Reference numerals: 1. the method comprises the following steps of (1) crushing and grinding, 2) mixing and briquetting, 3, thermosetting, 4, crushing and screening, 5, low-temperature chlorination, 6, cooling and heat exchange, 7, refining, 8, high-temperature oxidation, 9 and deoxidizing and cooling.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention, and it is obvious that the described embodiments are some, but not all, embodiments of the present invention. It should be noted that the examples are only for illustrating the technical solutions of the present invention, and not for limiting the same.

FIG. 1 is a schematic flow chart of a method for producing titanium dioxide by low-temperature chlorination of a titanium-rich material.

Example 1

Referring to fig. 1, the method for producing titanium dioxide by low-temperature chlorination of a titanium-rich material used in this embodiment includes a crushing and grinding step 1, a mixed briquetting step 2, a heat curing step 3, a crushing and screening step 4, a low-temperature chlorination step 5, a cooling and heat exchanging step 6, a refining step 7, a high-temperature oxidation step 8, and a deoxidation and cooling step 9, and the method is performed according to the following steps:

1) in the crushing and grinding process 1, the titanium-rich material is added with carbon powder and a binder to be crushed and ground to obtain fine mineral powder;

2) in the mixed briquetting process 2, fine mineral powder and the fine powder from the crushing and screening process 4 are uniformly mixed and pressed into briquettes;

3) in the heat curing process 3, the pressed block exchanges heat with hot nitrogen from the cooling heat exchange process 6 to realize heat curing to obtain a cured material;

4) in the crushing and screening process 4, the solidified material is crushed and screened to obtain a chlorination raw material and fine powder meeting the particle size requirement of the fluidization chlorination reaction, and the fine powder returns to the mixing and briquetting process 2 for recycling;

5) in the low-temperature chlorination step 5, the chlorination raw material reacts with chlorine and circulating chlorine to obtain crude titanium tetrachloride and chlorination slag, and the chlorination slag is subjected to environment-friendly treatment;

6) in the cooling heat exchange process 6, the hot material from the low-temperature chlorination process 5 exchanges heat with nitrogen to obtain cold material and hot nitrogen, the cold material returns to the low-temperature chlorination process 5, and the hot nitrogen is sent to the hot curing process 3;

7) in the refining step 7, the crude titanium tetrachloride is refined to obtain refined titanium tetrachloride;

8) in the high-temperature oxidation process 8, the fine titanium tetrachloride reacts with oxygen at high temperature to obtain titanium dioxide and oxygen-containing chlorine;

9) in the deoxidation cooling process 7, oxygen-containing chlorine gas is deoxidized under the action of a deoxidizer, and is cooled to obtain circulating chlorine gas, and the circulating chlorine gas is returned to the low-temperature chlorination process 5 to be used as a chlorinating agent.

Example 2

In this example, the method for producing titanium dioxide by low-temperature chlorination of a titanium-rich material described in example 1 is adopted, and the titanium-rich material is vanadium-titanium magnetite concentrate direct reduction melting titanium slag containing 40% of TiO25% of CaO and 13% of MgO. In the crushing and grinding step 1, the carbon powder is activated carbon, and the binder is phenolic resin. In the crushing and grinding process 1, the adding mass of the carbon powder is 10% of the mass of the titanium-rich material, and the adding mass of the binder is 1% of the mass of the titanium-rich material. In the crushing and grinding step 1, the average particle size of the ground mixed fine mineral powder is controlled to be 0.1 μm. In the mixed briquetting step 2, the fine ore powder is pressed and formed, wherein the pressure is 0.3 MPa. In the thermosetting step 3, the temperature of hot nitrogen is 400 ℃ and the curing temperature is 100 ℃. The crushing and screeningIn step 4, the average sieve particle size of the chlorinated raw material was controlled to 60 μm. In the low-temperature chlorination procedure 5, the reactor is a gas-solid fluidized bed, the chlorination temperature is 400 ℃, the average residence time is 30min, and the titanium chlorination rate is 93%. In the cooling heat exchange process 6, the hot material from the low-temperature chlorination process 5 is cooled to 200 ℃ through heat exchange with nitrogen, the cooled material returns to the low-temperature chlorination process 5, and the circulation amount of the material in unit time is 1 time of the processing amount of the titanium-rich material in unit time. In the deoxidation cooling process 9, the deoxidizer is coal powder, the deoxidation temperature is 400 ℃, the average retention time is 30min, the oxygen content of chlorine is less than 2%, and the chlorine after deoxidation is cooled to below 200 ℃, and then the low-temperature chlorination process is returned.

Example 3

In this example, the method for producing titanium dioxide by low-temperature chlorination of a titanium-rich material described in example 1 is adopted, and the titanium-rich material is synthetic rutile and contains 98% of TiO2. In the crushing and grinding process 1, the carbon powder is metallurgical coke, and the binder is sucrose. In the crushing and grinding process 1, the adding mass of the carbon powder is 50% of the mass of the titanium-rich material, and the adding mass of the binder is 10% of the mass of the titanium-rich material. In the crushing and grinding step 1, the average particle size of the ground mixed fine mineral powder is controlled to be 50 μm. In the mixed briquetting step 2, the fine ore powder is pressed and formed, wherein the pressure is 20 MPa. In the thermosetting step 3, the hot nitrogen temperature was 680 ℃ and the curing temperature was 650 ℃. In the crushing and screening step 4, the average screened particle size of the chlorinated raw material is controlled to be 300 μm. In the low-temperature chlorination procedure 5, the reactor is a gas-solid fluidized bed, the chlorination temperature is 680 ℃, the average residence time is 240min, and the titanium chlorination rate is 99%. In the cooling heat exchange process 6, the hot material from the low-temperature chlorination process 5 is cooled to 350 ℃ through heat exchange with nitrogen, the cooled material returns to the low-temperature chlorination process 5, and the circulation amount of the material in unit time is 15 times of the processing amount of the titanium-rich material in unit time. In the deoxidation cooling process 9, the deoxidizer is activated carbon, the deoxidation temperature is 800 ℃, the average retention time is 90min, the oxygen content of the chlorine is less than 1%, the chlorine after deoxidation is cooled to below 200 ℃, and the low-temperature chlorination process is returned.

Example 4

In this example, the method for producing titanium dioxide by low-temperature chlorination of a titanium-rich material described in example 1 is adopted, and the titanium-rich material is high-titanium slag containing 92% of TiO2. In the crushing and grinding process 1, the carbon powder is petroleum coke, and the binder is starch. In the crushing and grinding process 1, the adding mass of the carbon powder is 35% of that of the titanium-rich material, and the adding mass of the binder is 5% of that of the titanium-rich material. In the crushing and grinding step 1, the average particle size of the ground mixed fine mineral powder is controlled to be 5 μm. In the mixed briquetting step 2, the fine ore powder is pressed and formed, wherein the pressure is 8 MPa. In the thermosetting step 3, the hot nitrogen temperature is 580 ℃ and the curing temperature is 550 ℃. In the crushing and screening step 4, the average screened particle size of the chlorinated raw material is controlled to be 150 μm. In the low-temperature chlorination procedure 5, the reactor is a gas-solid fluidized bed, the chlorination temperature is 600 ℃, the average residence time is 180min, and the titanium chlorination rate is 98%. In the cooling heat exchange process 6, the hot material from the low-temperature chlorination process 5 is cooled to 300 ℃ through heat exchange with nitrogen, the cooled material returns to the low-temperature chlorination process 5, and the circulation amount of the material in unit time is 10 times of the processing amount of the titanium-rich material in unit time. In the deoxidation cooling process 9, the deoxidizer is metallurgical coke, the deoxidation temperature is 600 ℃, the average retention time is 60min, the oxygen content of the chlorine is less than 1.2%, the chlorine after deoxidation is cooled to below 200 ℃, and the low-temperature chlorination process is returned.

Example 5

In this example, the method for producing titanium dioxide by low-temperature chlorination of a titanium-rich material described in example 1 is adopted, and the titanium-rich material is natural rutile and contains 94% of TiO2. In the crushing and grinding process 1, the carbon powder is pulverized coal, and the binder is asphalt. In the crushing and grinding process 1, the adding mass of the carbon powder is 36% of that of the titanium-rich material, and the adding mass of the binder is 6% of that of the titanium-rich material. In the crushing and grinding step 1, the average particle size of the ground mixed fine mineral powder is controlled to be 8 μm. In the mixed briquetting step 2, the fine ore powder is pressed and formed, wherein the pressure is 10 MPa. In the thermosetting step 3, the temperature of hot nitrogen is 480 ℃ and the curing temperature is 450 ℃. In the crushing and screening step 4, the average screened particle size of the chlorinated raw material is controlled to 130And mu m. In the low-temperature chlorination procedure 5, the reactor is a gas-solid fluidized bed, the chlorination temperature is 550 ℃, the average residence time is 180min, and the titanium chlorination rate is 98%. In the cooling heat exchange process 6, the hot material from the low-temperature chlorination process 5 is cooled to 280 ℃ through heat exchange with nitrogen, the cooled material returns to the low-temperature chlorination process 5, and the circulation amount of the material in unit time is 11 times of the processing amount of the titanium-rich material in unit time. In the deoxidation cooling process 9, the deoxidizer is petroleum coke, the deoxidation temperature is 500 ℃, the average residence time is 50min, the oxygen content of the chlorine is less than 0.5%, the chlorine after deoxidation is cooled to below 200 ℃, and the low-temperature chlorination process is returned.

Example 6

In this example, the method for producing titanium dioxide by low-temperature chlorination of a titanium-rich material described in example 1 is adopted, and the titanium-rich material is high calcium magnesium acid soluble titanium slag containing 75% of TiO21.8 percent of CaO and 7.5 percent of MgO. In the crushing and grinding process 1, the carbon powder is petroleum coke, and the binder is polyvinyl alcohol. In the crushing and grinding process 1, the adding mass of the carbon powder is 25% of that of the titanium-rich material, and the adding mass of the binder is 6% of that of the titanium-rich material. In the crushing and grinding step 1, the average particle size of the ground mixed fine mineral powder is controlled to be 10 μm. In the mixed briquetting step 2, the fine ore powder is pressed and formed, wherein the pressure is 10 MPa. In the thermosetting step 3, the temperature of hot nitrogen is 480 ℃ and the curing temperature is 450 ℃. In the crushing and screening step 4, the average screened particle size of the chlorinated raw material is controlled to 130 μm. In the low-temperature chlorination procedure 5, the reactor is a gas-solid fluidized bed, the chlorination temperature is 550 ℃, the average residence time is 180min, and the titanium chlorination rate is 97%. In the cooling heat exchange process 6, the hot material from the low-temperature chlorination process 5 is cooled to 280 ℃ through heat exchange with nitrogen, the cooled material returns to the low-temperature chlorination process 5, and the circulation amount of the material in unit time is 7 times of the processing amount of the titanium-rich material in unit time. In the deoxidation cooling process 9, the deoxidizer is carbon monoxide, the deoxidation temperature is 500 ℃, the average retention time is 30min, the oxygen content of the chlorine is less than 0.5%, the chlorine after deoxidation is cooled to below 200 ℃, and the low-temperature chlorination process is returned.

Example 7

In this example, the method for producing titanium dioxide by low-temperature chlorination of the titanium-rich material described in example 1 is adopted, and the titanium-rich material is a waste denitration catalyst and contains 82% of TiO2、4.8%WO3、1.2%V2O5. In the crushing and grinding process 1, the carbon powder is petroleum coke, and the binder is polyvinyl alcohol. In the crushing and grinding process 1, the adding mass of the carbon powder is 35% of that of the titanium-rich material, and the adding mass of the binder is 6% of that of the titanium-rich material. In the crushing and grinding step 1, the average particle size of the ground mixed fine mineral powder is controlled to be 10 μm. In the mixed briquetting step 2, the fine ore powder is pressed and formed, wherein the pressure is 10 MPa. In the thermosetting step 3, the temperature of hot nitrogen is 480 ℃ and the curing temperature is 450 ℃. In the crushing and screening step 4, the average screened particle size of the chlorinated raw material is controlled to 130 μm. In the low-temperature chlorination procedure 5, the used reactor is a gas-solid fluidized bed, the chlorination temperature is 550 ℃, the average residence time is 180min, the titanium chlorination rate is 99%, the tungsten chlorination rate is 99.5%, and the vanadium chlorination rate is 99.8%. In the cooling heat exchange process 6, the hot material from the low-temperature chlorination process 5 is cooled to 280 ℃ through heat exchange with nitrogen, the cooled material returns to the low-temperature chlorination process 5, and the circulation amount of the material in unit time is 7 times of the processing amount of the titanium-rich material in unit time. In the deoxidation cooling process 9, the deoxidizer is carbon monoxide, the deoxidation temperature is 500 ℃, the average retention time is 30min, the oxygen content of the chlorine is less than 0.5%, the chlorine after deoxidation is cooled to below 200 ℃, and the low-temperature chlorination process is returned.

The present invention may be embodied in many different forms and modifications may be effected therein by one skilled in the art without departing from the spirit and scope of the invention as defined in the appended claims.

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