Method for preparing rich titanium material from fused and separated titanium slag

Abstract

This invention discloses a method for upgrading molten titanium slag to prepare titanium-rich materials, belonging to the field of comprehensive resource utilization technology. The method includes: grinding titanium slag obtained from hydrogen reduction and electric furnace smelting of vanadium-titanium magnetite concentrate to a certain particle size; thoroughly mixing the titanium slag obtained in the first step with ammonium sulfate and activated carbon, placing it in a muffle furnace, and reacting it for a period of time at 400-600℃ to obtain a roasted product; leaching the roasted product obtained in the second step with dilute sulfuric acid at a certain temperature to obtain leaching residue and leachate; and leaching the obtained leaching residue with sodium hydroxide solution to obtain titanium-rich materials. This invention achieves the upgrading of molten titanium slag, and the produced titanium-rich materials can be used in the sulfuric acid process or chloride process to produce titanium dioxide, providing a new approach for the comprehensive utilization of molten titanium slag.

Description

Technical Field

[0001] This invention belongs to the field of comprehensive resource utilization technology, and mainly relates to a method for upgrading titanium slag to prepare titanium-rich materials. Background Technology

[0002] Vanadium-titanium magnetite is a composite mineral resource containing iron, vanadium, and titanium, with titanium being known as the "space metal." Vanadium-titanium magnetite is a globally recognized strategic resource, widely used in national defense, metallurgy, chemical engineering, aerospace, electronics, and materials science. my country is one of the countries with relatively abundant vanadium-titanium magnetite resources, ranking third in the world in reserves. These resources are mainly located in the Panzhihua-Xichang region of Sichuan, Chengde in Hebei, Daixian in Shanxi, and Hanzhong in Shaanxi.

[0003] In my country, the traditional blast furnace process is mainly used to process vanadium-titanium magnetite concentrate. During blast furnace smelting, most of the titanium ends up in the titanium-containing blast furnace slag, which is difficult to utilize due to its low grade. The direct hydrogen reduction-electric furnace smelting two-step process, as a new generation of non-blast furnace smelting technology, is considered an effective method for the comprehensive utilization of vanadium-titanium magnetite. After ironmaking from ilmenite concentrate using the direct reduction-electric furnace method, a large amount of titanium-containing slag is produced, also known as smelted titanium slag. The composition, phases, and titanium content of smelted titanium slag differ significantly from those of titanium-containing blast furnace slag obtained through the blast furnace process. Specifically, its titanium content (calculated as titanium dioxide) reaches over 40 wt.%, which is 2 to 4 times that of titanium-containing blast furnace slag; the main titanium-containing phases in smelted titanium slag are pseudobrite and a small amount of rutile, while the main titanium-containing phase in titanium-containing blast furnace slag is perovskite. Although non-blast furnace smelting processes avoid the slag-making process of traditional blast furnace smelting, greatly improving the titanium grade in titanium slag, the grade of molten titanium slag is generally only 40 wt.%~50 wt.%, and the main impurities are iron, aluminum, calcium, magnesium, etc. Further impurity removal and enrichment of titanium are needed to make it into titanium-rich material for better utilization.

[0004] Currently, there are no reports on the enrichment of molten titanium slag to prepare titanium-rich materials. Only studies on obtaining titanium-containing blast furnace slag using blast furnace processes have been reported. These studies can provide some insights into the enrichment of molten titanium slag. Chinese patent CN103882241B discloses a method for preparing titanium-rich materials from titanium-containing blast furnace slag through boric acid melting treatment. This process utilizes the low melting point of boric acid (169℃) and its ability to react with SiO2. Its activity is enhanced at temperatures below 300℃. Hydrochloric acid is then used to leach and dissolve the main impurities SiO2, CaO, MgO, Al2O3, and Fe2O3, while titanium remains in the filter residue, thus achieving the preparation of titanium-rich materials. Chinese patent CN107354252A discloses a method for the resource-based disposal of titanium-containing blast furnace slag and a method for obtaining titanium-rich materials. This process first uses magnetic separation to remove iron, and then further uses high-concentration hydrochloric acid leaching combined with alkaline leaching to obtain titanium-rich materials. All of the above processes can utilize titanium-containing blast furnace slag to prepare titanium-rich materials, with the main purpose of removing impurities such as SiO2, CaO, MgO, Al2O3, and Fe2O3. If high-concentration acid leaching is used directly, titanium may also be leached out, leading to the loss of titanium resources. If the acid leaching temperature is further increased, the leached titanium can be hydrolyzed and enter the titanium-rich material, but the titanium-rich material obtained by hydrolysis has a finer particle size and is difficult to filter. Summary of the Invention

[0005] This invention addresses the problem of resource utilization of molten titanium slag by providing a method for upgrading molten titanium slag to prepare titanium-rich materials. The method achieves efficient separation of impurity ions in the preparation of titanium-rich materials while avoiding the loss of titanium.

[0006] The technical solution of the present invention: A method for upgrading molten titanium slag to prepare titanium-rich materials includes the following steps: Step 1: Grind the titanium slag obtained by hydrogen reduction and electric furnace smelting of vanadium-titanium magnetite concentrate to obtain finely ground smelted titanium slag; Step 2: The finely ground titanium slag obtained in Step 1 is thoroughly mixed with ammonium sulfate and activated carbon in a certain mass ratio and then placed in a muffle furnace. The mixture is heated to a certain temperature and reacted for a period of time to obtain the calcined product. Step 3: The roasted product obtained in Step 2 is leached with dilute sulfuric acid of a certain concentration at a certain temperature for a period of time and then filtered to obtain leaching residue 1 and leaching liquid 1. Step 4: The leaching residue 1 obtained in step 3 is leached with a sodium hydroxide solution of a certain concentration at a certain temperature for a period of time and then filtered to obtain leaching residue 2, which is the titanium-rich material.

[0007] Preferably, the particle size of the finely ground titanium slag in step 1 is below 150 μm.

[0008] Preferably, the reaction temperature in step 2 is 350~600℃ and the reaction time is 10~180min.

[0009] Preferably, the mass ratio of the molten titanium slag to ammonium sulfate in step 2 is 1:1 to 1:5, and the mass ratio of the molten titanium slag to activated carbon is 1:0.1 to 1:0.5.

[0010] Preferably, the mass concentration of sulfuric acid in step 3 is 5% to 25%.

[0011] Preferably, the leaching temperature in step 3 is 40~80℃ and the leaching time is 30~120min.

[0012] Preferably, the mass concentration of sodium hydroxide in step 4 is 2.5% to 20%.

[0013] Preferably, the leaching temperature in step 4 is 40~100℃ and the leaching time is 60~180min.

[0014] This invention utilizes the principle that titanium oxide and ammonium sulfate exist as titanium dioxide in the presence of activated carbon and at a suitable temperature. Impurity ions such as iron, aluminum, calcium, and magnesium react with ammonium sulfate to form sulfates. These impurities can then be removed by acid leaching, thus enriching titanium. The reaction pathway may be as follows: ammonium sulfate sulfates impurities such as titanium, iron, calcium, magnesium, and aluminum in the molten titanium slag, generating the corresponding sulfates. Due to the poor thermal stability of titanium sulfate, it can decompose at low temperatures in the presence of activated carbon, generating larger particles of titanium dioxide, while other sulfates are more stable. Further acid leaching separates the aforementioned impurities, and alkaline leaching separates silicon dioxide, yielding a titanium-rich material. The obtained titanium-rich material has larger particles, is easier to filter, and can be used in the production of titanium dioxide using the sulfuric acid or chloride process.

[0015] The above method utilizes the highly reactive substances such as ammonium bisulfate and sulfur dioxide produced by heating ammonium sulfate, which can sulfatate impurities such as iron, calcium, magnesium, and aluminum in the molten titanium slag and convert them into corresponding sulfates. Activated carbon acts as a reducing agent, so that titanium exists in the form of oxides and is not sulfatated. Furthermore, the sulfates of iron, calcium, and magnesium can be separated by acid leaching, and silicon dioxide can be separated by alkaline leaching, which significantly increases the titanium content in the molten titanium slag.

[0016] Compared with the prior art, the present invention has the following advantages: (1) The reaction temperature of the present process is greatly reduced compared with that of electric furnace smelting, and the overall energy consumption is greatly reduced; (2) The reaction conditions of the present process are mild; (3) The present invention has a simple process, is easy to operate, has low production cost, and has industrial application prospects. Attached Figure Description

[0017] Figure 1 This is a process flow diagram of the present invention. Detailed Implementation

[0018] The present invention will be described in detail below with reference to the embodiments, but the scope of protection of the present invention is not limited to the following embodiments.

[0019] The chemical composition (mass percentage) of the molten titanium slag used in the following examples is as follows: 10.50% FeO, 48.80% TiO2, 7.45% Al2O3, 23.82% SiO2, 4.80% CaO, 4.36% MgO; XRD analysis results show that the main phases in the molten titanium slag are Fe2TiO5, Mg2Ti2O5, TiO2 and SiO2. Example 1

[0020] (1) The titanium slag obtained by hydrogen reduction and electric furnace smelting of vanadium-titanium magnetite concentrate is ground to below 150μm to obtain finely ground smelted titanium slag.

[0021] (2) The finely ground titanium slag obtained in step (1) is thoroughly mixed with ammonium sulfate and activated carbon at a mass ratio of 1:3:0.1 and placed in a muffle furnace. The mixture is heated to 500℃ and reacted for 120 min to obtain the calcined product.

[0022] (3) The roasted product obtained in step (2) is leached with 15% dilute sulfuric acid at 80°C for 120 min and filtered to obtain leaching residue 1 and leaching liquid 1.

[0023] (4) The leaching residue 1 obtained in step (3) is leached with a 20% sodium hydroxide solution at 40°C for 60 min and filtered to obtain leaching residue 2, which is the titanium-rich material.

[0024] The titanium-rich material contains 88.2% titanium dioxide and has an acid hydrolysis rate of 92.2%.

[0025] Example 2 (1) The titanium slag obtained by hydrogen reduction and electric furnace smelting of vanadium-titanium magnetite concentrate is ground to below 150μm to obtain finely ground smelted titanium slag.

[0026] (2) The finely ground titanium slag obtained in step (1) is thoroughly mixed with ammonium sulfate and activated carbon at a mass ratio of 1:1:0.3 and placed in a muffle furnace. The mixture is heated to 350℃ and reacted for 180 min to obtain the calcined product.

[0027] (3) The roasted product obtained in step (2) was leached with 5% dilute sulfuric acid at 40°C for 30 min and filtered to obtain leaching residue 1 and leaching liquid 1.

[0028] (4) The leaching residue 1 obtained in step (3) is leached at 100°C for 180 min with a sodium hydroxide solution of 2.5% by mass and filtered to obtain leaching residue 2, which is the titanium-rich material.

[0029] The titanium-rich material contains 84.3% titanium dioxide and has an acid hydrolysis rate of 93.1%. Example 3

[0030] (1) The titanium slag obtained by hydrogen reduction and electric furnace smelting of vanadium-titanium magnetite concentrate is ground to below 150μm to obtain finely ground smelted titanium slag.

[0031] (2) The finely ground titanium slag obtained in step (1) is thoroughly mixed with ammonium sulfate and activated carbon at a mass ratio of 1:5:0.5 and placed in a muffle furnace. The mixture is heated to 450℃ and reacted for 60 minutes to obtain the calcined product.

[0032] (3) The roasted product obtained in step (2) was leached with 20% dilute sulfuric acid at 60°C for 90 min and filtered to obtain leaching residue 1 and leaching liquid 1.

[0033] (4) The leaching residue 1 obtained in step (3) is leached at 80°C for 100 min with a 10% sodium hydroxide solution and filtered to obtain leaching residue 2, which is the titanium-rich material.

[0034] The titanium-rich material contains 88.4% titanium dioxide and has an acid hydrolysis rate of 93.2%. Example 4

[0035] (1) The titanium slag obtained by hydrogen reduction and electric furnace smelting of vanadium-titanium magnetite concentrate is ground to below 150μm to obtain finely ground smelted titanium slag.

[0036] (2) The finely ground titanium slag obtained in step (1) is thoroughly mixed with ammonium sulfate and activated carbon at a mass ratio of 1:4:0.2 and placed in a muffle furnace. The mixture is heated to 600℃ and reacted for 10 min to obtain the calcined product.

[0037] (3) The roasted product obtained in step (2) is leached with dilute sulfuric acid with a mass fraction of 25% at 80°C for 120 min and filtered to obtain leaching residue 1 and leaching liquid 1.

[0038] (4) The leaching residue 1 obtained in step (3) is leached with a 15% sodium hydroxide solution at 55°C for 60 min and filtered to obtain leaching residue 2, which is the titanium-rich material.

[0039] The titanium-rich material contains 82.8% titanium dioxide and has an acid hydrolysis rate of 91.5%.

[0040] Comparative Example 1

[0041] (1) The titanium slag obtained by hydrogen reduction and electric furnace smelting of vanadium-titanium magnetite concentrate is ground to below 150μm to obtain finely ground smelted titanium slag.

[0042] (2) The finely ground titanium slag obtained in step (1) is thoroughly mixed with 98% concentrated sulfuric acid and activated carbon in a mass ratio of 1:3:0.1 and placed in a muffle furnace. The mixture is heated to 500℃ and reacted for 120 min to obtain the calcined product.

[0043] (3) The roasted product obtained in step (2) is leached with 15% dilute sulfuric acid at 80°C for 120 min and filtered to obtain leaching residue 1 and leaching liquid 1.

[0044] (4) The leaching residue 1 obtained in step (3) is leached with a 20% sodium hydroxide solution at 40°C for 60 min and filtered to obtain leaching residue 2, which is the titanium-rich material.

[0045] In step (2), replacing ammonium sulfate with 98% concentrated sulfuric acid affects the roasting atmosphere and causes environmental problems. Furthermore, the titanium dioxide content in the titanium-rich material is 80.3%, and the acid hydrolysis rate reaches 87.1%, both of which are reduced.

[0046] Comparative Example 2

[0047] (1) The titanium slag obtained by hydrogen reduction and electric furnace smelting of vanadium-titanium magnetite concentrate is ground to below 150μm to obtain finely ground smelted titanium slag.

[0048] (2) The finely ground titanium slag obtained in step (1) is thoroughly mixed with ammonium sulfate and activated carbon at a mass ratio of 1:3:0.1 and placed in a muffle furnace. The mixture is heated to 500℃ and reacted for 120 min to obtain the calcined product.

[0049] (3) The roasted product obtained in step (2) is leached with sulfuric acid of 55% by mass at 80°C for 120 min and filtered to obtain leaching residue 1 and leaching liquid 1.

[0050] (4) The leaching residue 1 obtained in step (3) is leached with a 20% sodium hydroxide solution at 40°C for 60 min and filtered to obtain leaching residue 2, which is the titanium-rich material.

[0051] In step (3), 55% sulfuric acid was used to replace 15% dilute sulfuric acid, which caused titanium dioxide to dissolve and the yield was not high. In the end, the titanium dioxide content in the titanium-rich material was 75.3% and the acid hydrolysis rate was 81.1%.

[0052] Comparative Example 3

[0053] (1) The titanium slag obtained by hydrogen reduction and electric furnace smelting of vanadium-titanium magnetite concentrate is ground to below 150μm to obtain finely ground smelted titanium slag.

[0054] (2) The finely ground titanium slag obtained in step (1) is thoroughly mixed with ammonium sulfate and activated carbon at a mass ratio of 1:3:0.1 and placed in a muffle furnace. The mixture is heated to 500℃ and reacted for 120 min to obtain the calcined product.

[0055] (3) The roasted product obtained in step (2) is leached with 15% dilute sulfuric acid at 80°C for 120 min and filtered to obtain leaching residue 1 and leaching liquid 1.

[0056] (4) The leaching residue 1 obtained in step (3) is leached with a 30% sodium hydroxide solution at 40°C for 60 min and filtered to obtain leaching residue 2, which is the titanium-rich material.

[0057] Replacing the 20% sodium hydroxide solution with a 30% sodium hydroxide solution in step (4) will result in the formation of sodium titanate, increasing the sodium content. The titanium dioxide content in the titanium-rich material is 76.2%, and the acid hydrolysis rate reaches 78.8%.

[0058] The above embodiments are only used to illustrate and not limit the technical solutions of the present invention. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that various modifications and changes can be made to the exemplary embodiments of the present invention without departing from the spirit and scope defined by the claims.

Claims

1. A method for upgrading molten titanium slag to prepare titanium-rich materials, characterized in that, Includes the following steps: Step 1: Grind the titanium slag obtained by hydrogen reduction and electric furnace smelting of vanadium-titanium magnetite concentrate to obtain finely ground smelted titanium slag; Step 2: The finely ground titanium slag obtained in Step 1 is thoroughly mixed with ammonium sulfate and activated carbon in a certain mass ratio and then placed in a muffle furnace. The mixture is heated to a certain temperature and reacted for a period of time to obtain the calcined product. Step 3: The roasted product obtained in Step 2 is leached with dilute sulfuric acid of a certain concentration at a certain temperature for a period of time and then filtered to obtain leaching residue 1 and leaching liquid 1. Step 4: The leaching residue 1 obtained in step 3 is leached with a sodium hydroxide solution of a certain concentration at a certain temperature for a period of time and then filtered to obtain leaching residue 2, which is the titanium-rich material.

2. The method for upgrading molten titanium slag to prepare titanium-rich materials according to claim 1, characterized in that, The particle size of the finely ground and melted titanium slag in step 1 is less than 150 μm.

3. The method for preparing titanium-rich materials by upgrading molten titanium slag according to claim 1, characterized in that, The reaction temperature in step 2 is 350~600℃, and the reaction time is 10~180min.

4. The method for preparing titanium-rich materials by upgrading molten titanium slag according to claim 1, characterized in that, In step 2, the mass ratio of the molten titanium slag to ammonium sulfate is 1:1 to 1:5, and the mass ratio of the molten titanium slag to activated carbon is 1:0.1 to 1:0.

5.

5. The method for preparing titanium-rich materials by upgrading molten titanium slag according to claim 1, characterized in that, The mass concentration of sulfuric acid in step 3 is 5% to 25%.

6. The method for preparing titanium-rich materials by upgrading molten titanium slag according to claim 1, characterized in that, The leaching temperature in step 3 is 40~80℃, and the leaching time is 30~120min.

7. The method for preparing titanium-rich materials by upgrading molten titanium slag according to claim 1, characterized in that, The mass concentration of sodium hydroxide in step 4 is 2.5% to 20%.

8. The method for preparing titanium-rich materials by upgrading molten titanium slag according to claim 1, characterized in that, The leaching temperature in step 4 is 40~100℃, and the leaching time is 60~180min.

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