Titanium concentrate low-concentration acidolysis method based on waste acid

Abstract

The invention discloses a waste acid-based titanium concentrate low-concentration acidolysis method, which comprises the following steps: mixing concentrated sulfuric acid, titanium concentrate and iron powder, adding waste acid under the protection of inert gas, carrying out acidolysis to obtain a titanium concentrate acidolysis solid-phase substance, and leaching to obtain an acidolysis titanium solution. According to the method, a method of coupling low-concentration acidolysis of the titanium concentrate and reduction of the acidolysis titanium solution is adopted, the low-concentration acidolysis efficiency of the titanium concentrate is improved, meanwhile, the production period is greatly shortened, and the stability of the production process is improved; according to the method, the utilization level of titanium resources and sulfur resources in the waste acid can be improved, and the titanium dioxide production efficiency of the sulfuric acid method can also be improved. The method is simple in process, low in cost and wide in market popularization prospect.

Description

Technical Field

[0001] This application relates to the field of chemical technology, and in particular to a method for low-concentration acidolysis of titanium concentrate based on waste acid. Background Technology

[0002] Titanium dioxide, as the inorganic pigment with the best whiteness, is widely used in coatings, plastics, papermaking, and inks. The main industrial production methods for titanium dioxide are the sulfuric acid process and the chloride process, with the sulfuric acid process accounting for approximately 86% of my country's titanium dioxide production. The sulfuric acid process generates a large amount of waste acid as a byproduct of the hydrolysis, producing 6-8 tons of titanium dioxide per ton of titanium dioxide annually, totaling over 24 million tons in my country. This waste acid contains approximately 20% sulfuric acid, as well as large amounts of impurities such as ferrous sulfate, magnesium sulfate, and titanium oxysulfate. Currently, the main methods for treating this waste acid are neutralization, concentration, phosphate rock leaching, and the production of polyferric sulfate. Neutralization methods neutralize waste acid with alkaline substances like lime or limestone, generating a large amount of solid waste titanium gypsum. Due to the complex composition of titanium gypsum, comprehensive utilization is difficult, and it is mainly stored, posing ecological risks and incurring high treatment costs, accounting for approximately 10% of the production cost of sulfuric acid-based titanium dioxide. Concentration methods utilize vacuum evaporation equipment to evaporate water from waste acid, increasing its concentration to obtain concentrated acid, which is then returned to the acidolysis process. However, this method suffers from problems such as scaling in the concentration system and high investment and operating costs. The leaching of phosphate rock method is unsuitable for most sulfuric acid-based titanium dioxide producers because waste acid is hazardous waste, long-distance transportation is difficult, and phosphate rock resources have regional characteristics. The production of polyferric sulfate is limited by a small market capacity and cannot be widely adopted. These methods inevitably suffer from high treatment costs, large equipment investments, and significant environmental impacts. Based on the low-concentration acidolysis of waste acid titanium concentrate, the waste acid can be directly and extensively used in the acidolysis process of sulfuric acid-based titanium dioxide, replacing part of the concentrated sulfuric acid, reducing concentrated sulfuric acid consumption, and enabling the recovery of titanium from the waste acid, while simultaneously improving production efficiency.

[0003] Although low-concentration acidolysis of waste titanium concentrate is universal, economical, and environmentally friendly, it is technically challenging. The key technical difficulty is the inability to control the acidolysis rate of titanium concentrate. The slow acidolysis rate results in a titanium yield that is about 15% lower than the normal level of 96%-97%, making industrial application impossible.

[0004] Therefore, developing a low-concentration acidolysis method for titanium concentrate based on waste acid is a problem that urgently needs to be solved by those skilled in the art. Summary of the Invention

[0005] In view of this, this application provides a method for directly applying waste acid from titanium dioxide production to the low-concentration acidolysis of titanium concentrate. This method can improve the level of waste acid reuse and the recovery level of titanium resources in waste acid, and utilize the heat generated during the reduction of titanium liquid by iron powder, thereby improving the efficiency and cleanliness of sulfuric acid process titanium dioxide production.

[0006] This application provides a method for low-concentration acidolysis of titanium concentrate based on waste acid, comprising:

[0007] Concentrated sulfuric acid, titanium concentrate, and iron powder are mixed, and waste acid is added under inert gas protection to carry out acid hydrolysis, obtaining an acid hydrolyzed solid phase of titanium concentrate, which is then leached to obtain an acid hydrolyzed titanium solution.

[0008] In some specific implementations, the concentrated sulfuric acid contains 92% to 98% sulfuric acid by mass; and the titanium concentrate has a grade of 45% to 48%.

[0009] In some specific implementations, the mass ratio of concentrated sulfuric acid to titanium concentrate is (1.48-1.59):1; the mass ratio of iron to titanium concentrate is (2-4):100.

[0010] In some specific implementations, the mixing temperature is 0°C to 30°C; the mixing time is 5 min to 10 min.

[0011] In some specific implementations, the mass fraction of the mixed acid after adding waste acid is 80% to 83%.

[0012] In some specific implementations, the mass fraction of the waste acid is 15 wt.% to 25 wt.%, and the mass ratio of the waste acid to titanium concentrate is (0.3-0.5):1.

[0013] In some specific implementations, the acidolysis is carried out under the protection of an inert gas, including nitrogen; the rate of the inert gas is 5 L / min to 10 L / min.

[0014] In some specific implementations, the concentration of trivalent titanium in the acid-hydrolyzed titanium solution is 1 g / L to 3 g / L.

[0015] In some specific implementations, the leaching includes dissolving soluble sulfates in the acid-hydrolyzed solid phase of titanium concentrate into a solution using demineralized water, wherein the mass ratio of the acid-hydrolyzed solid phase of titanium concentrate to the demineralized water is (4-7):5.

[0016] In some specific implementations, the leaching is a water bath leaching, and the temperature of the water bath leaching is 50°C to 80°C.

[0017] This application employs a coupled method of low-concentration acidolysis of titanium concentrate and reduction of the acidolyzed titanium solution to improve the efficiency of low-concentration acidolysis of titanium concentrate, while significantly reducing the production cycle and enhancing the stability of the production process. This method can improve the comprehensive utilization of titanium and sulfur resources in waste acid and also increase the production efficiency of titanium dioxide produced via the sulfuric acid process. The method is simple, low-cost, and has broad market prospects. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the low-concentration acidolysis process based on waste titanium concentrate in this application. Detailed Implementation

[0019] It should be understood that the expression “one or more of…” individually includes each of the objects described after the expression, as well as various different combinations of two or more of the described objects, unless otherwise understood from the context and usage. The expression “and / or” combined with three or more described objects should be understood to have the same meaning, unless otherwise understood from the context.

[0020] The terms “including,” “having,” or “containing,” including the use of their grammatical synonyms, should generally be understood as open-ended and non-restrictive, for example, not excluding other unstated elements or steps, unless otherwise specifically stated or understood from the context.

[0021] It should be understood that the order of steps or the sequence of actions is not important as long as this application remains operational. Furthermore, two or more steps or actions can be performed simultaneously.

[0022] The use of any and all instances or exemplary language such as “e.g.” or “include” in this document is intended merely to better illustrate the application and does not constitute a limitation on the scope of the application. No language in this specification should be construed as indicating that any unclaimed element is essential to the practice of this application.

[0023] Furthermore, the numerical ranges and parameters used to define this application are approximate values, and the relevant values ​​in the specific embodiments have been presented as precisely as possible. However, any numerical value inevitably contains standard deviations due to individual test methods. Therefore, unless otherwise explicitly stated, it should be understood that all ranges, quantities, values, and percentages used in this disclosure are modified with the word "approximately." Here, "approximately" generally means that the actual value is within plus or minus 10%, 5%, 1%, or 0.5% of a specific value or range.

[0024] To solve the above-mentioned technical problems, this application mainly couples the low-concentration acidolysis process of titanium concentrate with the reduction process of acidolysis titanium liquid, making full use of the heat generated in the reduction process of acidolysis titanium liquid and the ability of ferrous sulfate generated by the reduction of iron powder to carry bound water, thereby increasing the temperature and acid concentration in the low-concentration acidolysis process of titanium concentrate, and finally achieving low-concentration and efficient acidolysis of titanium concentrate.

[0025] This application provides a method for low-concentration acidolysis of titanium concentrate based on waste acid, comprising:

[0026] Concentrated sulfuric acid, titanium concentrate, and iron powder are mixed, and waste acid is added under inert gas protection to carry out acid hydrolysis, obtaining an acid hydrolyzed titanium concentrate solid phase. The leached product is then acid hydrolyzed titanium solution, which is desalted and leached.

[0027] A schematic diagram of the low-concentration acidolysis process for waste titanium concentrate is shown below. Figure 1As shown. This application first mixes concentrated sulfuric acid, titanium concentrate, and iron. Under inert gas protection, waste acid is added for acidolysis. After crystallization, separation, concentration, and hydrolysis, an acid-hydrolyzed titanium concentrate solid phase is obtained. Then, demineralized water is used to leach soluble sulfates from the titanium concentrate solid phase to obtain an acid-hydrolyzed titanium solution. In some specific implementations, the concentrated sulfuric acid has a sulfuric acid mass fraction of 92% to 98%, which can be 92%, 93%, 94%, 95%, 96%, 97%, or 98%; the titanium concentrate grade is 45% to 48%, which can be 45%, 46%, 47%, or 48%. In some specific implementations, the mass ratio of concentrated sulfuric acid to titanium concentrate is (1.48-1.59):1, which can be 1.48:1, 1.49:1, 1.5:1, 1.51:1, 1.52:1, 1.53:1, 1.54:1, 1.55:1, 1.56:1, 1.57:1, 1.58:1, or 1.59:1; the mass ratio of iron powder to titanium concentrate is (2-4):100, which can be 2:100, 2.5:100, 3:100, 3.5:100, or 4:100. In some specific implementations, the mixing temperature is 0℃ to 30℃; the mixing time is 5 min to 10 min. In some specific implementations, the mass fraction of the mixed acid after adding waste acid is 80% to 83%, which can be 80%, 80.5%, 81%, 81.5%, 82%, 82.5%, or 83%. In some specific implementations, the mass fraction of the waste acid is 15 wt.% to 25 wt.%, which can be 15 wt.%, 16 wt.%, 18 wt.%, 19 wt.%, 20 wt.%, 22 wt.%, 24 wt.%, or 25 wt.%, and the mass ratio of the waste acid to titanium concentrate is (0.3-0.5):1, which can be 0.3:1, 0.5:1, 0.4:1, 0.45:1, or 0.5:1. In some specific implementations, the acidolysis is carried out under an inert gas atmosphere, including nitrogen, argon, etc.; the inert gas flow rate is 5 L / min to 10 L / min. In some specific implementations, the concentration of trivalent titanium in the acid-hydrolyzed titanium solution is 1 g / L to 3 g / L. First, an inert gas is introduced into the continuous acid-hydrolyzed reactor to create an inert atmosphere. The reactor is then stirred, and the uniformly mixed material is added to the titanium concentrate acid-hydrolyzed reactor. Waste acid is added, with the amount calculated based on a mixed acid concentration of 80-83% (mass fraction) of waste acid and concentrated sulfuric acid. During the acid-hydrolyzed process, it is essential to maintain an inert atmosphere in the continuous acid-hydrolyzed reactor.

[0028] This application utilizes demineralized water to leach soluble sulfates from the acid-hydrolyzed solid phase of titanium concentrate to obtain an acid-hydrolyzed titanium solution. In some specific implementations, the mass ratio of the acid-hydrolyzed solid phase of titanium concentrate to demineralized water is (4-7):5, which can be 4:5, 4.5:5, 5:5, 5.5:5, 6:5, 6.5:5, or 7:5. In some specific implementations, the leaching is performed in a water bath at a temperature of 50°C to 80°C. After the acid-hydrolyzed solid phase of titanium concentrate exits the reactor, subsequent processes are carried out according to existing equipment and process conditions.

[0029] This application addresses the technical challenge of low acidolysis efficiency in the low-concentration process of titanium dioxide production using the existing sulfuric acid process by employing a coupled acidolysis and reduction method. This method improves both the utilization of titanium and sulfur resources in the waste acid and the production efficiency of the sulfuric acid process for titanium dioxide. The method is simple, low-cost, and has broad market prospects.

[0030] The present application is further illustrated below with reference to embodiments. The scope of protection of the present application is not limited to the following embodiments.

[0031] Example 1

[0032] This embodiment provides a low-concentration acidolysis method for titanium concentrate based on waste acid, including:

[0033] In the premixing tank, based on the tank's volume, 98% acid (concentrated sulfuric acid) and titanium concentrate were mixed at a mass ratio of 1.52:1, with acid added first and then ore added. After the titanium concentrate was added, reduced iron powder was added at a mass ratio of 2.3:100 (iron powder to titanium concentrate). The mixture was stirred for 5 minutes until homogeneous, and then placed into the feeding tank at 25°C. Inert nitrogen gas was introduced into the reactor at a rate of 10 L / min to ensure an inert atmosphere. The acid-ore mixture from the feeding tank was pumped into the reactor at a feed rate of 15.00 t / h. Waste acid was added at a rate of 2.14 t / h (the waste acid was added at a mass ratio of 20 wt.% to titanium concentrate of 0.36:1, resulting in an acid concentration of 83%). The reactor material temperature was monitored. 300 g of the acid-hydrolyzed solid phase of the titanium concentrate was taken from the reactor outlet, and 250 g of deionized water was added. The mixture was then leached in a 70°C water bath, and the acid hydrolysis rate and the amount of trivalent titanium (Ti) in the leachate were measured. 3+ The concentration is determined, and subsequent crystallization separation, concentration and hydrolysis processes are operated according to existing process conditions. Waste acid generated in the hydrolysis process is returned to the acid hydrolysis process.

[0034] Example 2

[0035] This embodiment provides a low-concentration acidolysis method for titanium concentrate based on waste acid, including:

[0036] In the premixing tank, based on the tank's volume, 98% acid and titanium concentrate were mixed at a mass ratio of 1.50:1, with acid added first and then ore added. After the titanium concentrate was added, reduced iron powder was added at a mass ratio of 2.3:100 to iron powder. The mixture was stirred for 5 minutes until homogeneous, and then placed into the feeding tank at 25°C. Inert nitrogen gas was introduced into the reactor at a rate of 10 L / min to maintain an inert atmosphere. The acid-ore mixture from the feeding tank was pumped into the reactor at a feed rate of 15.00 t / h. Waste acid was added at a rate of 2.70 t / h (the waste acid was added at a mass ratio of 20 wt.% to titanium concentrate of 0.45:1, resulting in an acid concentration of 80%). 300 g of the acid-hydrolyzed solid phase of the titanium concentrate was taken from the reactor outlet, and 250 g of deionized water was added. The mixture was then leached in a 70°C water bath, and the acid hydrolysis rate and the amount of trivalent titanium (Ti) in the leachate were measured. 3+ The concentration is determined, and subsequent crystallization separation, concentration and hydrolysis processes are operated according to existing process conditions. Waste acid generated in the hydrolysis process is returned to the acid hydrolysis process.

[0037] Example 3

[0038] This embodiment provides a low-concentration acidolysis method for titanium concentrate based on waste acid, including:

[0039] In the premixing tank, based on the tank's volume, 98% acid and titanium concentrate were mixed at a mass ratio of 1.48:1, with acid added first and then ore added. After the titanium concentrate was added, reduced iron powder was added at a mass ratio of 2.3:100 to iron powder. The mixture was stirred for 5 minutes until homogeneous, and then placed into the feeding tank at 25°C. Inert nitrogen gas was introduced into the reactor at a rate of 10 L / min to maintain an inert atmosphere. The acid-ore mixture from the feeding tank was pumped into the reactor at a feed rate of 15.00 t / h. Waste acid was added at a rate of 2.66 t / h (the waste acid was added at a mass ratio of 20 wt.% to titanium concentrate of 0.44:1, resulting in an acid concentration of 80%). 300 g of the acid-hydrolyzed solid phase of the titanium concentrate was taken from the reactor outlet, and 250 g of deionized water was added. The mixture was then leached in a 70°C water bath, and the acid hydrolysis rate and the amount of trivalent titanium (Ti) in the leachate were measured. 3+ The concentration is determined, and subsequent crystallization separation, concentration and hydrolysis processes are operated according to existing process conditions. Waste acid generated in the hydrolysis process is returned to the acid hydrolysis process.

[0040] Example 4

[0041] This embodiment provides a low-concentration acidolysis method for titanium concentrate based on waste acid, including:

[0042] In the premixing tank, based on the tank's volume, 98% acid and titanium concentrate were mixed at a mass ratio of 1.59:1, acid first, then ore. After adding the titanium concentrate, reduced iron powder was added at a mass ratio of 2.3:100 (iron powder to titanium concentrate). The mixture was stirred for 5 minutes until homogeneous, and then placed into the feeding tank at 25°C. Inert nitrogen gas was introduced into the reactor at a rate of 10 L / min to maintain an inert atmosphere. The acid-ore mixture from the feeding tank was pumped into the reactor at a rate of 15.00 t / h. Waste acid was added at a rate of 2.78 t / h (the waste acid was added at a mass ratio of 20 wt.% to titanium concentrate of 0.48:1, resulting in an acid concentration of 80%). 300 g of the acid-hydrolyzed solid phase of the titanium concentrate was taken from the reactor outlet, and 250 g of deionized water was added. The mixture was then leached in a 70°C water bath, and the acid hydrolysis rate and the amount of trivalent titanium (Ti) in the leachate were measured. 3+ The concentration is determined, and subsequent crystallization separation, concentration and hydrolysis processes are operated according to existing process conditions. Waste acid generated in the hydrolysis process is returned to the acid hydrolysis process.

[0043] Example 5

[0044] This embodiment provides a low-concentration acidolysis method for titanium concentrate based on waste acid, including:

[0045] In the premixing tank, based on the tank's volume, 98% acid and titanium concentrate were mixed at a mass ratio of 1.51:1, with acid added first and then ore added. After the titanium concentrate was added, reduced iron powder was added at a mass ratio of 2.3:100 to iron powder. The mixture was stirred for 5 minutes until homogeneous, and then placed into the feeding tank at 25°C. Inert nitrogen gas was introduced into the reactor at a rate of 10 L / min to ensure an inert atmosphere. The acid-ore mixture from the feeding tank was pumped into the reactor at a feed rate of 15.00 t / h. Waste acid was added at a rate of 2.63 t / h (the waste acid was added at a mass ratio of 18 wt.% to titanium concentrate of 0.44:1, resulting in an acid concentration of 80%). 300 g of the acid-hydrolyzed solid phase of the titanium concentrate was taken from the reactor outlet, and 250 g of deionized water was added. The mixture was then leached in a 70°C water bath, and the acid hydrolysis rate and the amount of trivalent titanium (Ti) in the leachate were measured. 3+ The concentration is determined, and subsequent crystallization separation, concentration and hydrolysis processes are operated according to existing process conditions. Waste acid generated in the hydrolysis process is returned to the acid hydrolysis process.

[0046] Example 6

[0047] This embodiment provides a low-concentration acidolysis method for titanium concentrate based on waste acid, including:

[0048] In the premixing tank, based on the tank's volume, 98% acid and titanium concentrate were mixed at a mass ratio of 1.47:1, with acid added first and then ore added. After the titanium concentrate was added, reduced iron powder was added at a mass ratio of 2.3:100 to iron powder. The mixture was stirred for 5 minutes until homogeneous, and then placed into the feeding tank at 25°C. Inert nitrogen gas was introduced into the reactor at a rate of 10 L / min to maintain an inert atmosphere. The acid-ore mixture from the feeding tank was pumped into the reactor at a feed rate of 15.00 t / h. Waste acid was added at a rate of 2.91 t / h (the waste acid was added at a mass ratio of 20 wt.% to titanium concentrate of 0.48:1, resulting in an acid concentration of 80%). 300 g of the acid-hydrolyzed solid phase of the titanium concentrate was taken from the reactor outlet, and 250 g of deionized water was added. The mixture was then leached in a 70°C water bath, and the acid hydrolysis rate and the amount of trivalent titanium (Ti) in the leachate were measured. 3+ The concentration is determined, and subsequent crystallization separation, concentration and hydrolysis processes are operated according to existing process conditions. Waste acid generated in the hydrolysis process is returned to the acid hydrolysis process.

[0049] Comparative Example 1

[0050] This comparative example provides a low-concentration acidolysis method for titanium concentrate based on waste acid, including:

[0051] In the premixing tank, based on the tank's volume, 98% acid (concentrated sulfuric acid, 98.0% by mass) was mixed with titanium concentrate at a mass ratio of 1.52:1, acid first, then ore. The mixture was stirred for 5 minutes until homogeneous, and kept at 25°C. This mixture was then placed in the feeding tank, and the acid-ore mixture was pumped into the reactor at a feed rate of 15.00 t / h. Waste acid was added at a rate of 1.96 t / h (the waste acid addition was based on a waste acid (20 wt.%) to titanium concentrate mass ratio of 0.33:1). 300 g of the acid-hydrolyzed solid phase of the titanium concentrate was taken from the reactor outlet, and 250 g of deionized water was added. The mixture was then leached in a 70°C water bath, and the acid hydrolysis rate and the amount of trivalent titanium (Ti) in the leachate were measured. 3+ The concentration is determined, and subsequent crystallization separation, concentration and hydrolysis processes are operated according to existing process conditions. Waste acid generated in the hydrolysis process is returned to the acid hydrolysis process.

[0052] The acidolysis rate and the amount of trivalent titanium (Ti) in the leachate were tested using the low-concentration acidolysis method for titanium concentrate based on waste acid provided in Examples 1-6 and Comparative Example 1. 3+ Concentration, the test method is as follows:

[0053] Acid hydrolysis rate:

[0054] The titanium dioxide content was determined according to YB T 159.1-2015 Determination of Titanium Dioxide Content in Titanium Concentrate (Rock Minerals) - Ferric Ammonium Sulfate Titration Method. The acid hydrolysis rate was calculated using the following formula:

[0055] Acidolysis rate, %; C, titanium dioxide concentration in titanium solution, g / L; V, volume of titanium solution, L; m, mass of titanium concentrate, g; W, mass fraction of titanium dioxide in titanium concentrate. Trivalent titanium concentration: Pipette 10 mL of the sample into a 250 mL reagent bottle, add 5 mL of 5% ammonium thiocyanate indicator, and titrate with ferric ammonium sulfate standard solution (concentration C, g / L) until the endpoint is reached (no fading after 30 seconds). Record the volume of standard solution consumed, V (L). Calculation formula: .

[0056] The results are shown in Table 1.

[0057] Table 1

[0058]

[0059] Note: The titanium recovered from the waste acid is calculated as titanium dioxide, and its concentration is 4 g / L.

[0060] As shown in the results of the embodiments and comparative examples of this application, the low-concentration acidolysis of waste titanium concentrate has a good effect, resulting in high waste acid reuse and high titanium recovery from waste acid. Specifically, the acidolysis rate is high by 0.51-1.56%, the trivalent titanium concentration is high by 2.0-2.2 g / L, the waste acid reuse is high by 0.03-0.15 kg / t of ore, and the titanium recovery from waste acid is high by 0.09-0.46 kg / t of ore. In addition, this application combines reduction and acidolysis into one process, reducing the reduction operation, shortening the production time by 6 hours, and improving production efficiency.

[0061] The above description is merely a preferred embodiment of this application, but the scope of protection of this application is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in this application, based on the technical solution and application concept of this application, should be included within the scope of protection of this application.

Claims

1. A method for low-concentration acidolysis of titanium concentrate based on waste acid, characterized in that, include: Concentrated sulfuric acid, titanium concentrate, and iron powder are mixed, and waste acid is added under inert gas protection to carry out acid hydrolysis, obtaining an acid hydrolyzed solid phase of titanium concentrate, which is then leached to obtain an acid hydrolyzed titanium solution.

2. The method according to claim 1, characterized in that, The concentrated sulfuric acid contains 92% to 98% sulfuric acid by mass; the titanium concentrate has a grade of 45% to 48%.

3. The method according to claim 1, characterized in that, The mass ratio of concentrated sulfuric acid to titanium concentrate is (1.48-1.59):1; the mass ratio of iron to titanium concentrate is (2-4):

100.

4. The method according to claim 1, characterized in that, The mixing temperature is 0°C to 30°C; the mixing time is 5 min to 10 min.

5. The method according to claim 1, characterized in that, The mass fraction of the mixed acid after adding waste acid is 80% to 83%.

6. The method according to claim 1, characterized in that, The waste acid has a mass fraction of 15 wt.% to 25 wt.%, and the mass ratio of the waste acid to titanium concentrate is (0.3-0.5):

1.

7. The method according to claim 1, characterized in that, The acidolysis is carried out under the protection of an inert gas, including nitrogen; the rate of the inert gas is 5 L / min to 10 L / min.

8. The method according to claim 1, characterized in that, The concentration of trivalent titanium in the acid-hydrolyzed titanium solution is 1 g / L to 3 g / L.

9. The method according to claim 1, characterized in that, The leaching process involves dissolving soluble sulfates in the acid-hydrolyzed solid phase of titanium concentrate into a solution using demineralized water, wherein the mass ratio of the acid-hydrolyzed solid phase of titanium concentrate to the demineralized water is (4-7):

5.

10. The method according to claim 1, characterized in that, The leaching is a water bath leaching, and the temperature of the water bath leaching is 50°C to 80°C.

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