阅读说明：本技术 一种二氧化钛的制备方法及其方法制备的四氯化钛和二氧化钛 (Titanium dioxide preparation method and titanium tetrachloride and titanium dioxide prepared by method ) 是由 武珠峰 银波 范协诚 刘兴平 宋高杰 于 2019-10-31 设计创作，主要内容包括：本发明公开了一种二氧化钛的制备方法,包括以下步骤：高钙镁富钛原料与氟化氢气体反应得到富钛料；富钛料与还原剂及氯气反应生成四氯化钛；四氯化钛与氧化剂反应生成二氧化钛。本发明还公开了一种四氯化钛,按照上述的二氧化钛制备方法中的前两个步骤的进行制备。另外,本发明还公开了一种二氧化钛,按照上述二氧化钛制备方法制备的得到。本发明的二氧化钛的制备方法降低了沸腾氯化法制备四氯化钛过程对于原料的要求,将低品位的钛矿用于四氯化钛制备,降低了生产成本。(The invention discloses a preparation method of titanium dioxide, which comprises the following steps: reacting the high-calcium-magnesium titanium-rich raw material with hydrogen fluoride gas to obtain a titanium-rich material; reacting the titanium-rich material with a reducing agent and chlorine to generate titanium tetrachloride; titanium tetrachloride reacts with an oxidant to produce titanium dioxide. The invention also discloses titanium tetrachloride which is prepared according to the first two steps in the titanium dioxide preparation method. In addition, the invention also discloses titanium dioxide prepared by the preparation method of the titanium dioxide. The preparation method of the titanium dioxide reduces the requirements of the boiling chlorination method for preparing the titanium tetrachloride for raw materials, uses the low-grade titanium ore for preparing the titanium tetrachloride, and reduces the production cost.)

1. A method of producing titanium dioxide, comprising:

reacting the high-calcium-magnesium titanium-rich raw material with hydrogen fluoride gas to obtain a titanium-rich material;

reacting the titanium-rich material with a reducing agent and chlorine to generate titanium tetrachloride;

titanium tetrachloride reacts with an oxidant to produce titanium dioxide.

2. The method for producing titanium dioxide according to claim 1, comprising the steps of:

step 1, reacting a high-calcium-magnesium titanium-rich raw material with hydrogen fluoride gas to obtain a titanium-rich material, and drying the titanium-rich material;

step 2, mixing the dried titanium-rich material with a reducing agent, and reacting with chlorine to generate crude titanium tetrachloride;

step 3, collecting and purifying the crude titanium tetrachloride to obtain refined titanium tetrachloride;

and 4, reacting the refined titanium tetrachloride with an oxidant, and oxidizing to generate titanium dioxide.

3. The method for preparing titanium dioxide according to claim 2, wherein the step 1 of drying the titanium-rich material is to dry the titanium-rich material obtained after the reaction by using a drying agent.

4. The method for producing titanium dioxide according to claim 3,

the step 1 specifically comprises the following steps:

s100: mixing the high-calcium-magnesium titanium-rich raw material with a drying agent in advance;

s101: reacting the uniformly mixed high-calcium magnesium titanium-rich raw material with hydrogen fluoride gas;

s102: the drying agent absorbs water generated in the reaction process, so that the titanium-rich material is dried;

s103: and separating the dried titanium-rich material from the drying agent.

5. The method for producing titanium dioxide according to claim 4,

in the step S100, the mass ratio of the high-calcium magnesium titanium-rich raw material to the drying agent is 1: 0.1-1.5;

the grain size of the drying agent is 1-3mm, and the drying agent is one of active carbon or calcium chloride.

6. The method for producing titanium dioxide according to claim 4,

in step S101, the high-calcium magnesium titanium-rich raw material and the hydrogen fluoride gas are reacted for 0.5 to 2 hours at the reaction condition of 30 to 80 ℃ in a mass ratio of 1:0.05 to 0.15.

7. The method for producing titanium dioxide according to claim 4,

in step S103, a screening separation method is adopted to separate the dried titanium-rich material and the drying agent, wherein the particle size of the titanium-rich material is 100-300 meshes, and the particle size of the drying agent is 1-3 mm.

8. The method for producing titanium dioxide according to claim 2,

in step 2, the molar ratio of the titanium-rich material to the reducing agent is 1:3-5, the reaction temperature is 1000-1100 ℃, the reaction pressure is 10-200KPa, and the reaction time is 36-48 h.

9. The method for producing titanium dioxide according to claim 8, wherein the reducing agent is one of petroleum coke, activated carbon, and semi coke.

10. The method for producing titanium dioxide according to claim 2,

the step 3 specifically comprises the following steps:

s301, filtering: filtering impurities in the crude titanium tetrachloride gas by using a bag filter, and collecting the filtered titanium tetrachloride gas;

s302 leaching: leaching the filtered titanium tetrachloride gas by using leacheate;

s303, cooling: cooling the washed titanium tetrachloride gas by using a water cooler to generate titanium tetrachloride liquid;

s304, rectification: and removing other metal chlorides and dissolved impurity gases in the titanium tetrachloride liquid by adopting a rectification system.

11. The method for producing titanium dioxide according to claim 2,

in the step 4, the refined titanium tetrachloride reacts with an oxidant, and the oxidation reaction of the excessive refined titanium tetrachloride and the oxidant is adopted to generate titanium dioxide, so that the titanium dioxide is obtained.

12. The method for producing titanium dioxide according to claim 11,

the oxidant is one of oxygen and ozone.

13. The method for producing titanium dioxide according to claim 4,

further comprising step S104: and (4) carrying out regeneration treatment on the separated drying agent, wherein the regeneration of the drying agent is used for removing moisture in the drying agent and recycling the drying agent.

14. The method for producing titanium dioxide according to claim 13,

the regeneration of the drying agent specifically comprises the following steps: and purging the drying agent by adopting nitrogen, wherein the temperature of the nitrogen is 120-200 ℃, and the purging time is 3-5 h.

15. Titanium tetrachloride produced by the method according to any one of claims 2 to 9, which is described in steps 1 to 3 of the titanium dioxide production method.

16. A titanium dioxide produced by the method for producing titanium dioxide according to any one of claims 1 to 14.

Technical Field

The invention particularly relates to a preparation method of titanium dioxide and titanium tetrachloride and titanium dioxide prepared by the method.

Background

Titanium has the advantages of small density, high specific strength, low thermal conductivity, good high temperature and low temperature resistance, strong corrosion resistance, good biocompatibility and the like, and is called as modern metal and strategic metal. Titanium and titanium alloy have important strategic significance to national defense, economy and scientific and technological development, and the titanium industrial development level is an important embodiment of national comprehensive strength. Production of TiCl by chlorination of titanium-rich raw material₄Is an important link in the titanium industry, and the advanced degree of the chlorination process is directly related to the economic benefit and the social benefit of a titanium smelting plant.

At present, the chlorination process mainly comprises boiling chlorination and molten salt chlorination at home and abroad, and the molten salt chlorination method has the advantage of wide application range of raw materials, but has low production capacity and low economical efficiency in a large-scale production process compared with the boiling chlorination process; compared with the fused salt chlorination, the boiling chlorination process has the advantages of high production efficiency, high yield, easy realization of continuous production and the like, is widely adopted at home and abroad, but is mainly applied to low-calcium magnesium materials because calcium and magnesium impurities can react with chlorine to generate CaCl in the chlorination reaction process₂And MgCl₂And CaCl₂And MgCl₂The catalyst is liquid at the chlorination temperature, and the accumulation in a bed layer can cause the problems of reaction raw material adhesion, blockage of a distribution plate of a chlorination reactor and the like, thereby seriously influencing the normal operation of a fluidized bed.

At present, the industrialized boiling chlorination technology has very strict requirements on the content of alkaline earth metals in a titanium-containing raw material, wherein the total content of calcium oxide and magnesium oxide cannot be higher than 2 percent. In fact, a large amount of titanium-containing natural minerals and artificial minerals contain a large amount of calcium and magnesium elements, and are difficult to separate by mineral separation. The high-grade titanium resources in China are deficient, and although extremely rich ilmenite resources are stored in the Panxi region in Sichuan, the ilmenite resources cannot be fully utilized for a long time because the conventional boiling chlorination technology cannot be adopted due to the high content of calcium and magnesium. In the prior art, the adhesion phenomenon is mostly relieved by changing the structure of the chlorination reactor, so that the structure of the reactor is complex, the operation is complex, and the problem is not solved fundamentally.

Disclosure of Invention

The technical problem to be solved by the invention is to provide a titanium dioxide preparation method and titanium tetrachloride and titanium dioxide prepared by the method, aiming at the defects in the prior art, the titanium dioxide preparation method reduces the requirements of a boiling chlorination method for preparing titanium tetrachloride for raw materials, and uses low-grade titanium ore (such as high-calcium-magnesium titanium-rich raw materials) for preparing titanium tetrachloride, thereby reducing the production cost, wherein the high-calcium-magnesium titanium-rich raw materials generally have higher contents of calcium oxide, magnesium oxide and silicon dioxide.

In order to solve the technical problems, the invention adopts the following technical scheme:

a method of producing titanium dioxide, comprising:

reacting the high-calcium-magnesium titanium-rich raw material with hydrogen fluoride gas to obtain a titanium-rich material;

reacting the titanium-rich material with a reducing agent and chlorine to generate titanium tetrachloride;

titanium tetrachloride reacts with an oxidant to produce titanium dioxide.

Preferably, the preparation method of the titanium dioxide specifically comprises the following steps:

step 1, reacting a high-calcium-magnesium titanium-rich raw material with hydrogen fluoride gas to obtain a titanium-rich material, and drying the titanium-rich material;

step 2, mixing the dried titanium-rich material with a reducing agent, and reacting with chlorine to generate crude titanium tetrachloride;

step 3, collecting and purifying the crude titanium tetrachloride to obtain refined titanium tetrachloride;

and 4, reacting the refined titanium tetrachloride with an oxidant, and oxidizing to generate titanium dioxide.

Preferably, the step 1 of drying the titanium-rich material is to dry the titanium-rich material obtained after the reaction by using a drying agent.

Further preferably, the step 1 specifically includes the following steps:

s100: mixing the high-calcium-magnesium titanium-rich raw material with a drying agent in advance;

s101: and (3) reacting the uniformly mixed high-calcium magnesium titanium-rich raw material with hydrogen fluoride gas.

Wherein, the chemical reaction equation in step S101 is:

2HF+CaO→CaF₂+H₂O；

2HF+MgO→MgF₂+H₂O；

4HF+SiO₂→SiF₄+2H₂O；

s102: the drying agent absorbs water generated in the reaction process, so that the titanium-rich material is dried;

s103: and separating the dried titanium-rich material from the drying agent.

Wherein, the dried titanium-rich material mainly contains TiO₂、Fe₃O₄、CaF₂And MgF₂。

Preferably, in the step S100, the mixing mass ratio of the high-calcium magnesium titanium-rich raw material to the drying agent is 1: 0.1-1.5;

the grain size of the drying agent is 1-3mm, and the drying agent is one of active carbon or calcium chloride.

Preferably, in step S101, the high-calcium magnesium titanium-rich raw material and the hydrogen fluoride gas are reacted for 0.5 to 2 hours at the mass ratio of 1:0.05 to 0.15 and the reaction condition of 30 to 80 ℃.

Preferably, in step S103, the dried titanium-rich material and the drying agent are separated by a screening separation method, wherein the screening separation method is based on the principle that the titanium-rich material and the drying agent have different particle sizes, wherein the particle size of the titanium-rich material is 100-300 mesh, and the particle size of the drying agent is 1-3 mm.

Preferably, in step 2, the molar ratio of the titanium-rich material to the reducing agent is 1:3-5, the reaction temperature is 1000-1100 ℃, the reaction pressure is 10-200KPa, and the reaction time is 36-48 h.

Preferably, the reducing agent is one of petroleum coke, activated carbon and semi coke; the density of the titanium-rich material is greatly different from that of the reducing agent (wherein the density of the titanium-rich material is 4.25 g/cm)³The density of the petroleum coke is 0.9-1.1 g/cm³The density of the semi-coke is 1.0-1.3 g/cm³The density of the activated carbon is 0.33-0.38 g/cm³) And the titanium-rich material and the reducing agent are not contacted uniformly to influence the chlorination reaction effect, so that the titanium-rich material (with the particle size of 100-300 meshes) and the carbonaceous reducing agent (with the particle size not more than 200 meshes) are mixed and granulated according to the molar ratio of 1:3-5, the obtained particles are more uniform in texture, and the chlorination reaction effect is favorably improved.

Preferably, the reducing agent is semi-coke.

Wherein, the reducing agent in the step 2 firstly mixes TiO in the titanium-rich material₂Reducing the titanium to Ti, and then reacting the Ti with chlorine to generate crude titanium tetrachloride, wherein the generated crude titanium tetrachloride is gas; further, the fluoride generated at step S101, i.e., CaF₂And MgF₂Does not react with the reducing agent and chlorine gas, remains solid, so that the crude titanium tetrachloride gas produced is easily separated from the fluoride impurities, and the fluoride SiF produced in step S101₄As a gas, SiF before step 2₄The gas is separated from the solid mixture rich in titanium.

Preferably, the step 3 of collecting and purifying the crude titanium tetrachloride to obtain the refined titanium tetrachloride specifically comprises the following steps:

s301, filtering: filtering impurities in the crude titanium tetrachloride gas by using a bag filter, and collecting the filtered titanium tetrachloride gas, wherein the S301 step is used for removing titanium-rich material solids and reducing agent solids which are included in the crude titanium tetrachloride gas;

s302 leaching: leaching the filtered titanium tetrachloride gas by using leacheate to remove part of other metal chlorides such as ferric trichloride and the like in the titanium tetrachloride gas;

s303, cooling: cooling the washed titanium tetrachloride gas by using a water cooler to generate titanium tetrachloride liquid, wherein the step S303 is used for condensing the titanium tetrachloride gas to generate the titanium tetrachloride liquid; wherein, the water cooler is generally cooled by water with the temperature of 25-35 ℃.

S304, rectification: a rectification system is used to remove other metal chlorides and dissolved impurity gases from the titanium tetrachloride liquid, and step S304 is used to obtain refined titanium tetrachloride liquid.

Preferably, in the step 4, the fine titanium tetrachloride reacts with the oxidant, and the oxidation reaction of the excess fine titanium tetrachloride and the oxidant is performed to generate titanium dioxide, so as to obtain titanium dioxide, wherein the excess fine titanium tetrachloride reacts with the oxidant, so that the tail gas after the reaction does not contain the oxidant, which is convenient for the separation work at the rear end.

Further preferably, in step 4, the oxidant is one of oxygen and ozone.

Preferably, step 1 further includes step S104: and (4) carrying out regeneration treatment on the separated drying agent, wherein the regeneration of the drying agent is used for removing moisture in the drying agent so as to enable the drying agent to be recycled.

Preferably, the regeneration of the drying agent specifically comprises the following steps: and purging the drying agent by adopting nitrogen, wherein the temperature of the nitrogen is 120-200 ℃, and the purging time is 3-5 h.

Preferably, the content of calcium and magnesium in the high-calcium-magnesium titanium-rich raw material is 5-8% by mass.

The invention also provides titanium tetrachloride which is prepared by adopting the method in the steps 1-3 in the titanium dioxide preparation method.

The invention also provides titanium dioxide prepared by the preparation method of the titanium dioxide.

The preparation method of titanium dioxide provided by the invention converts calcium and magnesium impurities in the high-calcium-magnesium titanium-rich raw material into high-melting-point calcium fluoride and magnesium fluoride, solves the problems that the high-calcium-magnesium titanium-rich raw material generates low melting points such as calcium chloride and magnesium chloride in the chlorination reaction process, and high boiling point substances cause the blockage of the chlorination reaction furnace, greatly reduces the requirements of the boiling chlorination method for preparing titanium tetrachloride, can use low-grade titanium ore in China for preparing titanium tetrachloride and titanium dioxide, reduces the production cost, and simultaneously improves the technical level of the titanium industry in China.

Drawings

FIG. 1 is a flow chart of a process for producing titanium dioxide in an example of the present invention.

Detailed Description

The technical solutions in the present invention will be described clearly and completely with reference to the accompanying drawings, and it is obvious that the described embodiments are some, but not all embodiments of the present invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the scope of the present invention.

The invention provides a preparation method of titanium dioxide, which comprises the following steps:

reacting the high-calcium-magnesium titanium-rich raw material with hydrogen fluoride gas to obtain a titanium-rich material;

reacting the titanium-rich material with a reducing agent and chlorine to generate titanium tetrachloride;

titanium tetrachloride reacts with an oxidant to produce titanium dioxide.

The invention also provides titanium tetrachloride which is prepared by adopting the method in the steps 1-3 in the titanium dioxide preparation method.

The invention also provides titanium dioxide prepared by the preparation method of the titanium dioxide.

Example 1:

as shown in fig. 1, this embodiment provides a method for preparing titanium dioxide, which includes the following steps:

reacting the high-calcium-magnesium titanium-rich raw material with hydrogen fluoride gas to obtain a titanium-rich material;

reacting the titanium-rich material with a reducing agent and chlorine to generate titanium tetrachloride;

titanium tetrachloride reacts with an oxidant to produce titanium dioxide.

Specifically, the preparation method of titanium dioxide in this embodiment includes the following steps:

step 1, reacting a high-calcium-magnesium titanium-rich raw material with hydrogen fluoride gas to obtain a titanium-rich material, and drying the titanium-rich material;

in this embodiment, the step 1 of drying the titanium-rich material is to dry the titanium-rich material obtained after the reaction by using a drying agent.

In step 1, the method specifically comprises the following steps:

s100: mixing the high-calcium-magnesium titanium-rich raw material with a drying agent in advance; wherein the mass ratio of the high-calcium magnesium titanium-rich raw material to the drying agent is 1: 0.1; the particle size of the drying agent is 2mm, the drying agent is one of activated carbon or calcium chloride, and the drying agent is activated carbon in the embodiment.

S101: reacting the uniformly mixed high-calcium magnesium titanium-rich raw material with hydrogen fluoride gas; wherein the mass ratio of the high-calcium magnesium titanium-rich raw material to the hydrogen fluoride gas is 1:0.05, and the reaction is carried out for 2 hours at the temperature of 50 ℃.

S102: the drying agent absorbs water generated in the reaction process, so that the titanium-rich material is dried; namely, the titanium-rich material is dried by adopting activated carbon.

S103: separating the dried titanium-rich material from the drying agent; in this embodiment, a screening separation method is adopted to separate the dried titanium-rich material and the drying agent, that is, the screening separation method is adopted to separate the dried titanium-rich material and the activated carbon, wherein the particle size of the dried titanium-rich material is 100-300 meshes, and the particle size of the activated carbon is 2 mm.

Step 2, mixing the dried titanium-rich material with a reducing agent, and reacting with chlorine to generate crude titanium tetrachloride; wherein the molar ratio of the titanium-rich material to the reducing agent is 1:3, the reaction temperature is 1000 ℃, the reaction pressure is 200KPa, and the reaction time is 36 h; the reducing agent is one of petroleum coke, activated carbon and semi-coke, and in this embodiment, the petroleum coke is selected as the reducing agent.

Step 3, collecting and purifying the crude titanium tetrachloride to obtain refined titanium tetrachloride;

the step 3 specifically comprises the following steps:

s301, filtering: filtering impurities in the crude titanium tetrachloride gas by using a bag filter, and collecting the filtered titanium tetrachloride gas;

s302 leaching: leaching the filtered titanium tetrachloride gas by using leacheate;

s303, cooling: cooling the washed titanium tetrachloride gas by using a water cooler to generate titanium tetrachloride liquid, wherein the water cooler in the embodiment generally adopts water with the temperature of 25 ℃ for cooling;

s304, rectification: removing other metal chlorides and dissolved impurity gases in the titanium tetrachloride liquid by using a rectification system, wherein the metal chlorides are mainly ferric chloride; the impurity gas is mainly Cl₂And CO, CO₂。

Step 4, reacting the refined titanium tetrachloride with an oxidant, and oxidizing to generate titanium dioxide; in the step 4, excessive fine titanium oxide and the oxidant are used for oxidation reaction to obtain titanium dioxide; generally, the mass ratio of the adopted refined titanium tetrachloride to the oxidant is 6.5-8: in this embodiment, the mass ratio of the adopted refined titanium tetrachloride to the oxidizing agent is 8: 1; the oxidant is one of oxygen and ozone, and in the embodiment, the oxidant is oxygen.

Preferably, step 1 further includes step S104: the separated drying agent is subjected to regeneration treatment, and the regeneration of the drying agent is used for removing moisture in the drying agent so as to enable the drying agent to be recycled; and (3) purging the drying agent by adopting nitrogen, wherein the temperature of the nitrogen is 120 ℃, the purging time is 5h, and the regenerated activated carbon drying agent is reused.

Specifically, a high-calcium-magnesium titanium-rich raw material with 5-8% of calcium and magnesium in mass percentage and an activated carbon drying agent with the particle size of 2mm are added into an enamel stirred tank reactor according to the mass ratio of the high-calcium-magnesium titanium-rich raw material to the activated carbon of 1:0.1 to be uniformly mixed, hydrogen fluoride gas is introduced into the bottom of the enamel stirred tank reactor, wherein the mass ratio of the high-calcium-magnesium titanium-rich raw material to the hydrogen fluoride gas is 1:0.05, and the reaction is carried out for 2 hours at the temperature of 50 ℃; wherein, the hydrogen fluoride reacts with calcium oxide in the high-calcium magnesium titanium-rich raw material to generateCalcium fluoride and water are generated, hydrogen fluoride and magnesium oxide react to generate magnesium fluoride and water, hydrogen fluoride and silicon oxide react to generate silicon tetrafluoride and water, the water generated by the reaction is absorbed by activated carbon, and reaction tail gas is sent to a waste gas treatment system for treatment; obtaining a solid titanium-rich material after reaction, wherein the main component of the solid titanium-rich material comprises TiO₂、Fe₃O₄、CaF₂And MgF₂And then screening the solid titanium-rich material obtained after the reaction for separating the titanium-rich material from the active carbon drying agent. Adding the separated titanium-rich material and petroleum coke into a boiling chlorination reactor according to the molar ratio of 1:3 to perform chlorination reaction with chlorine, wherein the reaction temperature is 1000 ℃, the reaction pressure is 200KPa, the reaction time is 36h, the reaction generates crude titanium tetrachloride gas and metal chloride impurities, and the reaction tail gas sequentially enters a bag filter, a leaching tower and a cooling separator to be separated to obtain the fine titanium tetrachloride. The reaction tail gas firstly enters a bag filter, and unreacted raw materials, such as unreacted titanium-rich materials, carbonaceous reducing agent petroleum coke and the like, which are included in the tail gas are separated, wherein a filter element in the bag filter is made of metal sintering materials; and then the tail gas enters an elution tower, the tail gas is eluted by using an elution solution, the elution solution in the embodiment adopts a cold titanium tetrachloride solution, the reaction tail gas enters from a tower kettle of the elution tower, wherein an air inlet of the elution tower is 30-50cm below the liquid level of the tower kettle, in the embodiment, the air inlet of the elution tower is located 30cm below the liquid level of the tower kettle, and the reaction tail gas passes through the air inlet of the elution tower and is in countercurrent contact with the titanium tetrachloride spray solution from the top of the tower in the upward flowing process, so that other metal chloride impurities (such as FeCl) in the tail gas are caused to be in countercurrent₃) Cooled to be solid, the solid is gathered in the tower kettle and is discharged out of the leaching tower through the discharged residual liquid, in addition, part of titanium tetrachloride in the spraying liquid is heated to be changed into gas state, and the gas and the reaction tail gas come out from the top of the leaching tower to a cooling system for cooling and separation. Cooling tail gas from a leaching tower of a leaching tower in a cooling separator, wherein the cooling separator adopts a water cooler and adopts water with the temperature of 25 ℃ for cooling, and titanium tetrachloride gas in the tail gas is cooled into liquid and separated from non-condensable gas; tail gas discharged to rear end waste gas treatment system for removing titanium tetrachlorideThe system carries out treatment; and the titanium tetrachloride liquid enters a rectifying tower for rectification and purification, and is used for further removing other metal chlorides and dissolved impurity gases in the titanium tetrachloride liquid to obtain refined titanium tetrachloride liquid. And finally, evaporating the refined titanium tetrachloride liquid to obtain refined titanium tetrachloride vapor, and then mixing the refined titanium tetrachloride vapor with the mass ratio of 8: 1, mixing the refined titanium tetrachloride steam with oxygen, then carrying out oxidation reaction in an oxidation reactor to produce titanium dioxide and chlorine, wherein the tail gas after the reaction contains titanium dioxide powder, titanium tetrachloride and chlorine, filtering by using a bag filter to separate out the titanium dioxide powder, cooling the tail gas without the titanium dioxide to below 45 ℃, separating out the titanium tetrachloride in the tail gas, and returning the chlorine to the chlorination process for recycling.

Example 2:

as shown in fig. 1, this embodiment provides a method for preparing titanium dioxide, which includes the following steps:

reacting the high-calcium-magnesium titanium-rich raw material with hydrogen fluoride gas to obtain a titanium-rich material;

reacting the titanium-rich material with a reducing agent and chlorine to generate titanium tetrachloride;

titanium tetrachloride reacts with an oxidant to produce titanium dioxide.

Specifically, the preparation method of titanium dioxide in this embodiment includes the following steps:

step 1, reacting a high-calcium-magnesium titanium-rich raw material with hydrogen fluoride gas in advance to obtain a titanium-rich material, and drying the titanium-rich material;

in this embodiment, the step 1 of drying the titanium-rich material is to dry the titanium-rich material obtained after the reaction by using a drying agent.

In step 1, the method specifically comprises the following steps:

s100: mixing the high-calcium-magnesium titanium-rich raw material with a drying agent in advance; wherein the mass ratio of the high-calcium-magnesium titanium-rich raw material to the drying agent is 1: 1.5; the grain size of the drying agent is 1mm, the drying agent is one of active carbon or calcium chloride, and the drying agent in the embodiment adopts calcium chloride.

S101: reacting the uniformly mixed high-calcium magnesium titanium-rich raw material with hydrogen fluoride gas; wherein the mass ratio of the high-calcium magnesium titanium-rich raw material to the hydrogen fluoride gas is 1:0.15, and the reaction is carried out for 1h under the condition of 30 ℃.

S102: the drying agent absorbs water generated in the reaction process, so that the titanium-rich material is dried; namely, calcium chloride is adopted to dry the titanium-rich material.

S103: and separating the dried titanium-rich material from the drying agent. In this embodiment, a screening separation method is adopted to separate the dried titanium-rich material and the drying agent, that is, a screening separation method is adopted to separate the dried titanium-rich material and the calcium chloride, wherein the particle size of the titanium-rich material is 100-300 meshes, and the particle size of the calcium chloride is 1 mm.

Step 2, mixing the dried titanium-rich material with a reducing agent, and reacting with chlorine to generate titanium tetrachloride; wherein the molar ratio of the titanium-rich material to the reducing agent is 1:5, the reaction temperature is 1100 ℃, the reaction pressure is 10KPa, and the reaction time is 48 h; the reducing agent is one of petroleum coke, activated carbon and semi-coke, and the semi-coke is used as the reducing agent in the embodiment.

Step 3, collecting and purifying the crude titanium tetrachloride to obtain refined titanium tetrachloride;

the step 3 specifically comprises the following steps:

s301, filtering: filtering impurities in the crude titanium tetrachloride gas by using a bag filter, and collecting the filtered titanium tetrachloride gas;

s302 leaching: leaching the filtered titanium tetrachloride gas by using leacheate;

s303, cooling: cooling the washed titanium tetrachloride gas by using a water cooler to generate titanium tetrachloride liquid, wherein the water cooler in the embodiment generally adopts water with the temperature of 35 ℃ for cooling;

s304, rectification: removing other metal chlorides and dissolved impurity gases in the titanium tetrachloride liquid by adopting a rectification system, wherein the metal chlorides mainly comprise: FeCl₃(ii) a The impurity gases are mainly: CO and Cl₂And CO₂。

Step 4, reacting the refined titanium tetrachloride with an oxidant, and oxidizing to generate titanium dioxide; in the step 5, an excessive amount of titanium tetroxide and the oxidant are used for oxidation reaction to obtain titanium dioxide, and generally, the mass ratio of the adopted refined titanium tetrachloride to the oxidant is 6.5-8: in this example, the mass ratio of the adopted refined titanium tetrachloride to the adopted oxidant is 6.5: 1; the oxidant is one of oxygen and ozone, and in the embodiment, ozone is used as the oxidant.

Preferably, step 1 further includes step S104: the separated drying agent is subjected to regeneration treatment, and the regeneration of the drying agent is used for removing moisture in the drying agent so as to enable the drying agent to be recycled; and (3) purging the drying agent by adopting nitrogen, wherein the temperature of the nitrogen is 200 ℃, the purging time is 3h, and the regenerated calcium chloride drying agent is reused.

Specifically, a high-calcium magnesium titanium-rich raw material with 5-8% of calcium and magnesium in mass percentage and a calcium chloride drying agent with the particle size of 1mm are added into an enamel stirring reaction kettle reactor according to the mass ratio of 1:1.5 to be uniformly mixed, hydrogen fluoride gas is introduced into the bottom of the enamel reaction kettle, the mass ratio of the high-calcium magnesium titanium-rich raw material to the hydrogen fluoride gas is 1:0.15, the reaction is carried out for 1 hour under the condition of 30 ℃, the hydrogen fluoride reacts with calcium oxide in the high-calcium magnesium titanium-rich raw material to generate calcium fluoride and water, the hydrogen fluoride reacts with magnesium oxide to generate magnesium fluoride and water, the hydrogen fluoride reacts with silicon oxide to generate silicon tetrafluoride and water, the water generated by the reaction is absorbed by calcium chloride, and the reaction tail gas is treated in a waste gas treatment system; obtaining a solid titanium-rich material after reaction, wherein the main component of the solid titanium-rich material comprises TiO₂、Fe₃O₄、CaF₂And MgF₂And then screening the solid titanium-rich material obtained after the reaction for separating the titanium-rich material from the calcium chloride drying agent. And then adding the titanium-rich material obtained by separation and semi-coke in a molar ratio of 1:5 into a boiling chlorination reactor to perform chlorination reaction with chlorine at the reaction temperature of 1100 ℃ and the reaction pressure of 10KPa for 48 hours to generate crude titanium tetrachloride gas and metal chloride impurities, and allowing the reaction tail gas to sequentially enter a bag filter, a leaching tower and a cooling separator to separate out fine titanium tetrachloride. The reaction tail gas firstly enters a bag filter for separationUnreacted raw materials which are mixed in the tail gas are discharged, wherein the unreacted raw materials comprise unreacted titanium-rich materials, carbonaceous reducing agent semi-coke and the like, and a filter element in the bag filter is made of metal sintering materials; then the reaction tail gas enters an elution tower, the elution tower is used for eluting the tail gas, in the embodiment, cold titanium tetrachloride is used as the elution liquid, the reaction tail gas enters from a tower kettle of the elution tower, wherein an air inlet of the elution tower is 30-50cm below the liquid level of the tower kettle, an air inlet of the elution tower is 50cm below the liquid level of the tower kettle, the reaction tail gas passes through the air inlet of the elution tower and is in countercurrent contact with titanium tetrachloride spray liquid from the top of the tower in an upward flowing process, and other metal chloride impurities (such as FeCl) in the tail gas₃) Cooled to be solid and then gathered in the tower kettle, the residual liquid is discharged out of the leaching tower, part of titanium tetrachloride in the spraying liquid is heated to be changed into gas state, and the gas and the reaction tail gas are discharged from the top of the leaching tower to a cooling system for cooling and separation. The tail gas from the leaching tower of the leaching tower enters a cooling separator for cooling, the cooling separator in the embodiment adopts a water cooler and adopts water with the temperature of 35 ℃ for cooling, and the titanium tetrachloride gas in the tail gas is cooled into liquid and separated from the non-condensable gas; the tail gas from which the titanium tetrachloride is removed is discharged to a rear-end waste gas treatment system for treatment; the titanium tetrachloride liquid enters a rectifying tower for rectification and purification, and is used for further removing other metal chlorides and dissolved impurity gases in the titanium tetrachloride liquid to obtain the refined titanium tetrachloride liquid. Finally, evaporating the refined titanium tetrachloride liquid to obtain refined titanium tetrachloride vapor, and then mixing the refined titanium tetrachloride vapor with the mass ratio of 6.5: 1, mixing the refined titanium tetrachloride vapor with ozone, then carrying out oxidation reaction in an oxidation reactor to produce titanium dioxide and chlorine, wherein the tail gas after the reaction contains titanium dioxide powder, titanium tetrachloride and chlorine, filtering by using a bag filter to separate out the titanium dioxide powder, cooling the tail gas after removing the titanium dioxide to below 45 ℃, separating out the titanium tetrachloride in the tail gas, and returning the chlorine to the chlorination process for recycling.

Example 3:

as shown in fig. 1, this embodiment provides a method for preparing titanium dioxide, which includes the following steps:

reacting the high-calcium-magnesium titanium-rich raw material with hydrogen fluoride gas to obtain a titanium-rich material;

reacting the titanium-rich material with a reducing agent and chlorine to generate titanium tetrachloride;

titanium tetrachloride reacts with an oxidant to produce titanium dioxide.

Specifically, the preparation method of titanium dioxide in this embodiment includes the following steps:

step 1, reacting a high-calcium-magnesium titanium-rich raw material with hydrogen fluoride gas to obtain a titanium-rich material, and drying the titanium-rich material obtained after the reaction by adopting a drying agent;

in this embodiment, the drying of the titanium-rich material is to dry the titanium-rich material obtained after the reaction by using a drying agent.

In step 1, the method specifically comprises the following steps:

s100: mixing the high-calcium-magnesium titanium-rich raw material with a drying agent in advance; wherein the mixing mass ratio of the high-calcium-magnesium titanium-rich raw material to the drying agent is 1: 1.3; the grain size of the drying agent is 3mm, the drying agent is one of activated carbon or calcium chloride, and the drying agent in the embodiment adopts activated carbon.

S101: reacting the uniformly mixed high-calcium magnesium titanium-rich raw material with hydrogen fluoride gas; wherein the mass ratio of the high-calcium magnesium titanium-rich raw material to the hydrogen fluoride gas is 1:0.1, and the reaction is carried out for 0.5h under the condition of 80 ℃.

S102: the drying agent absorbs water generated in the reaction process, so that the titanium-rich material is dried; namely, the titanium-rich material is dried by adopting activated carbon.

S103: in this embodiment, the dried titanium-rich material and the drying agent are separated by a screening separation method, that is, the dried titanium-rich material and the activated carbon are separated by a screening separation method, wherein the particle size of the titanium-rich material is 100-300 meshes, and the particle size of the activated carbon is 3 mm.

Step 2, mixing the separated titanium-rich material with a reducing agent, and reacting with chlorine to generate crude titanium tetrachloride; wherein the molar ratio of the titanium-rich material to the reducing agent is 1: 4, the reaction temperature is 1050 ℃, the reaction pressure is 100KPa, and the reaction time is 40 h; the reducing agent is one of petroleum coke, activated carbon and semi coke, and the reducing agent is activated carbon in the embodiment.

Step 3, collecting and purifying the crude titanium tetrachloride to obtain refined titanium tetrachloride;

the step 3 specifically comprises the following steps:

s301, filtering: filtering impurities in the crude titanium tetrachloride gas by using a bag filter, and collecting the filtered titanium tetrachloride gas;

s302 leaching: leaching the filtered titanium tetrachloride gas by using leacheate;

s303, cooling: cooling the washed titanium tetrachloride gas by using a water cooler to generate titanium tetrachloride liquid, wherein the water cooler in the embodiment generally uses water with the temperature of 30 ℃ for cooling;

s304, rectification: removing other metal chlorides and dissolved impurity gases in the titanium tetrachloride liquid by adopting a rectification system, wherein the metal chlorides mainly comprise: FeCl₃(ii) a The impurity gases are mainly: cl₂CO and CO₂。

Step 4, reacting the refined titanium tetrachloride with an oxidant, and oxidizing to generate titanium dioxide; in the step 4, excessive titanium tetroxide and the oxidant are used for oxidation reaction to obtain titanium dioxide; generally, the mass ratio of the adopted refined titanium tetrachloride to the oxidant is 6.5-8: in this embodiment, the mass ratio of the adopted refined titanium tetrachloride to the adopted oxidant is 7: 1; the oxidant is one of oxygen and ozone, and oxygen is used as the oxidant in this embodiment.

Preferably, step 1 further includes step S104: the separated drying agent is subjected to regeneration treatment, and the regeneration of the drying agent is used for removing moisture in the drying agent so as to enable the drying agent to be recycled; and (3) purging the drying agent by adopting nitrogen, wherein the temperature of the nitrogen is 150 ℃, the purging time is 4h, and the regenerated active carbon drying agent is reused.

Specifically, a high-calcium-magnesium titanium-rich raw material with 5-8% of calcium and magnesium in mass percentage and an active carbon drying agent with the particle size of 3mm are added according to the mass ratio of 1:1.3Uniformly mixing in an enamel stirred tank reactor, introducing hydrogen fluoride gas to the bottom of the enamel stirred tank reactor, wherein the mass ratio of the high-calcium-magnesium titanium-rich raw material to the hydrogen fluoride gas is 1:0.1, and the reaction is carried out for 0.5h under the condition of 80 ℃, wherein the hydrogen fluoride reacts with calcium oxide in the high-calcium-magnesium titanium-rich raw material to generate calcium fluoride and water, the hydrogen fluoride reacts with magnesium oxide to generate magnesium fluoride and water, the hydrogen fluoride reacts with silicon oxide to generate silicon tetrafluoride and water, the water generated by the reaction is absorbed by calcium chloride, and the reaction tail gas is discharged to a waste gas treatment system for treatment; obtaining a solid titanium-rich material after reaction, wherein the main component of the solid titanium-rich material comprises TiO₂、Fe₃O₄、CaF₂And MgF₂And then screening the solid titanium-rich material after reaction for separating the titanium-rich material from the calcium chloride drying agent. Then, mixing the separated titanium-rich material and the activated carbon according to a molar ratio of 1: 4, adding the mixture into a boiling chlorination reactor according to the proportion to perform chlorination reaction with chlorine, wherein the reaction temperature is 1050 ℃, the reaction pressure is 100KPa, the reaction time is 40h, crude titanium tetrachloride gas and metal chloride impurities are generated by the reaction, and the reaction tail gas sequentially enters a bag filter, a leaching tower and a cooling separator to separate the titanium tetrachloride. The reaction tail gas firstly enters a bag filter, and unreacted raw materials included in the tail gas are separated, wherein the unreacted raw materials mainly comprise unreacted titanium-rich materials, carbonaceous reducing agent active carbon and the like; wherein, the filter element of the bag filter in the embodiment adopts metal sintered material; and then the tail gas enters an elution tower, the tail gas is eluted by using an elution solution, the elution solution adopted in the embodiment is a cold titanium tetrachloride solution, the reaction tail gas enters from a tower kettle of the elution tower, wherein an air inlet of the elution tower is 30-50cm below the liquid level of the tower kettle, an air inlet of the elution tower in the embodiment is 40cm below the liquid level of the tower kettle, the reaction tail gas passes through the air inlet of the elution tower and is in countercurrent contact with the titanium tetrachloride spray solution from the top of the tower in the upward flowing process, and other metal chloride impurities (such as FeCl) in the tail gas₃) Cooled to solid and then gathered in the tower kettle, discharged out of the leaching tower through residual liquid, heated part of titanium tetrachloride in the spraying liquid to be gaseous, and discharged out of the top of the leaching tower together with reaction tail gas to a cooling system for carrying outAnd (5) cooling and separating. Cooling tail gas from the leaching tower in a cooling separator, wherein the cooling separator in the embodiment adopts a water cooler and adopts water with the temperature of 30 ℃ for cooling, and titanium tetrachloride gas in the tail gas is cooled into liquid and separated from non-condensable gas; the tail gas from which the titanium tetrachloride is removed is discharged to a rear-end waste gas treatment system for treatment; the titanium tetrachloride liquid enters a rectifying tower for rectification and purification, and is used for further removing other metal chlorides and dissolved impurity gases in the titanium tetrachloride liquid to obtain the refined titanium tetrachloride liquid. Evaporating the fine titanium tetrachloride to obtain fine titanium tetrachloride steam, wherein the mass ratio of the fine titanium tetrachloride steam to the fine titanium tetrachloride steam is 7: 1, mixing the refined titanium tetrachloride steam with oxygen, then feeding the mixture into an oxidation reactor for oxidation reaction to produce titanium dioxide and chlorine, wherein the tail gas after the reaction contains titanium dioxide powder, titanium tetrachloride and chlorine, filtering the mixture by using a bag filter to separate out the titanium dioxide powder, cooling the tail gas after the titanium dioxide is removed to be below 45 ℃, separating out the titanium tetrachloride in the tail gas, and returning the chlorine to the chlorination process for recycling.

Example 4:

this example provides titanium tetrachloride, prepared as described in steps 1-3 of any one of the titanium dioxide preparation methods of examples 1-3.

Example 5:

the present example provides a titanium dioxide, prepared by the method of any one of examples 1-3.

It will be understood that the above embodiments are merely exemplary embodiments taken to illustrate the principles of the present invention, which is not limited thereto. It will be apparent to those skilled in the art that various modifications and improvements can be made without departing from the spirit and substance of the invention, and these modifications and improvements are also considered to be within the scope of the invention.