Method for enhancing impurity removal of high-calcium-magnesium titanium slag

Abstract

The invention discloses a method for enhancing impurity removal of high-calcium-magnesium titanium slag, which comprises the following steps of: S1, spraying gas added with NaCl into molten titanium slag to perform oxidation transformation treatment in the smelting and deslagging process of an ilmenite concentrate electric furnace; s2, the molten titanium slag obtained in the step 1 flows into an atomizer to be atomized, transformation of the titanium slag is further promoted, and the titanium slag is crushed into powder particles; and S3, the transformed titanium slag powder is subjected to impurity removal through a first-stage hydrochloric acid leaching process, and the titanium-rich material meeting the boiling chlorination requirement can be obtained. The method for strengthening impurity removal of the high-calcium-magnesium titanium slag is in butt joint with an existing titanium slag production process, heat of the molten titanium slag is fully utilized, rapid transformation of the titanium slag can be achieved, the titanium slag is crushed into powder particles, one-section leaching is adopted in acid leaching impurity removal of the transformed titanium slag, the process is short, energy consumption is low, and the method is suitable for industrial production. The method can realize low-cost preparation of the boiling chlorination furnace burden from the high-calcium-magnesium titanium slag, and has important significance for guaranteeing the supply safety of raw material resources in the titanium industry in China and promoting the high-quality development of the titanium industry in China.

Description

Technical Field

[0001] The invention belongs to the field of vanadium-titanium ore utilization, and particularly relates to a method for strengthening the removal of impurities from high-calcium-magnesium type titanium slag. Background Art

[0002] There are two main industrial production methods for titanium dioxide: chlorination and sulfuric acid. About 62.7% of the world's titanium dioxide is produced by chlorination, and the remaining 37.3% is produced by sulfuric acid. Since the product quality of titanium dioxide produced by chlorination is better than that of titanium dioxide produced by sulfuric acid, the chlorination method dominates the development trend of the titanium dioxide industry. However, the boiling chlorination method has strict requirements on the quality of titanium-containing raw materials. The boiling chlorination furnace charge must meet the requirements of TiO 2 Content>85%, CaO content<0.35%, MgO content<1.0%.

[0003] Although my country is a country with abundant titanium resources, the characteristics of high calcium and magnesium titanium raw materials make them unsuitable as raw materials for chloride titanium dioxide, especially for large-scale boiling chlorination equipment. For boiling chlorination equipment that has been built or is under construction, even if the enterprises have built high titanium slag equipment, they still rely on imported low calcium and magnesium titanium ore to smelt high titanium slag to meet the requirements of boiling chlorination. Therefore, the lack of stable supply of titanium raw materials in China has become one of the factors restricting the healthy development of the domestic chloride titanium dioxide industry.

[0004] The electric furnace titanium slag obtained after the high calcium and magnesium ilmenite concentrate in my country is smelted in an electric furnace. The calcium and magnesium content is high, and it is difficult to be directly used as a boiling chlorination charge to produce chloride titanium dioxide and sponge titanium. At present, the technical route adopted for the research on the removal of impurities from titanium slag to prepare boiling chlorination charge is mainly to convert the titanium in the titanium slag into insoluble rutile and the impurity elements into easily soluble mineral phases, so as to achieve the purpose of selective impurity removal and titanium enrichment. There are mainly two methods. One is to convert the impurity components in the titanium slag into easily soluble phases by adding sulfur dioxide, phosphoric acid, sodium alkali or sodium salt, phosphate and other additives for roasting, and then acid leaching for impurity removal. The additives are difficult to recycle, which not only increases the production cost, but also may affect the product quality. One is to adopt two-stage transformation treatment of oxidation roasting and reduction roasting for titanium slag, and then two-stage acid leaching for impurity removal, such as the UGS slag preparation process of Canada's QIT Company, which has problems such as high energy consumption and long process.

[0005] Therefore, in view of the above-mentioned problems existing in the current high-calcium-magnesium titanium slag impurity removal for preparing boiling chlorination furnace charge, the purpose of the present invention is to provide a method for strengthening the removal of impurities from high-calcium-magnesium titanium slag, which is connected to the existing titanium slag production process and directly transforms and crushes the liquid slag. The process is short and the energy consumption is low, which reduces the cost of titanium slag impurity removal and promotes the sustainable development of my country's titanium industry. Summary of the invention

[0006] The present invention provides the following technical solution: a method for strengthening the transformation and removal of impurities of titanium slag, comprising the following steps: S1: The molten titanium slag obtained by smelting ilmenite concentrate in an electric furnace is transported to a slag holding bucket with heating and heat preservation functions, so that the slag remains in a flowing state, and gas with NaCl is sprayed into the slag for oxidation transformation treatment; S2: the molten titanium slag obtained in step 1 is flowed into an atomizer for atomization treatment, and a high-speed gas injection system is used to atomize the liquid slag into titanium slag powder particles; S3 The transformed titanium slag powder is subjected to a one-stage hydrochloric acid leaching process to remove impurities, thereby obtaining a titanium-rich material that meets the boiling chlorination requirements.

[0007] Preferably, the titanium slag in step S1 contains TiO 2 ≥70wt%.

[0008] Preferably, in step S1, the gas sprayed includes one or more of oxygen, air, etc., and the spraying gas flow rate is 2-30m 3 / min•t slag, preferably 5~15m 3 / min•t slag, the blowing time is 2-30min. The blowing gas in step S1 of the present invention is preferably oxygen-rich gas for the purpose of oxidation transformation treatment to oxidize the low-valent titanium in the slag into rutile TiO 2 The purpose of injecting gas and adding NaCl is to increase the dissolution activity of impurities in the slag and provide favorable conditions for subsequent selective impurity removal by acid leaching.

[0009] Preferably, in step S1, the mass of the injected NaCl is controlled to be 0.2-2.5% of the slag, preferably 0.5-2.1%, and more preferably 1.5-2.1%, including a series of solutions such as 2.0%, 1.9-2.1%, and 1.8-2.05%.

[0010] Preferably, in step S2, the high-speed gas includes one or more of water vapor, oxygen, air, etc., and the gas flow rate is 0.05-0.5 m 3 / s, the gas pressure is 0.5~15MPa, and the gas flow rate is 20~500m / s. In the present invention, a high-speed gas (preferably oxygen-rich gas) injection system is used to atomize the liquid slag into titanium slag powder particles, and the controlled gas flow rate is 0.05~0.5m 3 / s, gas pressure is 0.5~15MPa, and gas flow rate is 20~500m / s. The purpose is to provide a certain cooling intensity to keep the silicates in the slag in a disintegrated state and not form a stable crystal structure, while achieving the purpose of crushing.

[0011] Preferably, the flow rate of the molten titanium slag atomization process in step S2 is 1-100 kg / min, preferably 30-60 kg / min.

[0012] Preferably, the particle size of the titanium slag after atomization in step S2 is 0.1 mm to 1 mm.

[0013] Preferably, in the hydrochloric acid leaching process in step S3, the hydrochloric acid concentration is 15-30wt%, the leaching temperature is 120-150°C, and the time is 1-4 hours. In the present invention, 15-30wt% hydrochloric acid leaching is used at 120-150°C, which will bring about favorable effects such as good impurity removal selectivity and high impurity removal rate.

[0014] Preferably, the titanium-rich material TiO obtained in step S3 2 ≥85%, CaO≤0.2%, MgO≤1.0%, and other relevant indicators meet the requirements of boiling chlorination.

[0015] The advantages of the present invention are: In view of the high energy consumption, long process and environmental problems of various methods for removing impurities from titanium slag to prepare boiling chlorination furnace charge, the present invention proposes a method for strengthening the removal of impurities from high calcium and magnesium type titanium slag, which is connected with the existing titanium slag production process and makes full use of the heat of molten titanium slag itself to achieve rapid transformation of titanium slag, improve the dissolution activity of impurities, and crush the titanium slag into powder particles. The transformed titanium slag is leached in hydrochloric acid for one-stage leaching to remove impurities. The added NaCl is dissolved in the acid leaching process and can be recovered for recycling. It has a short process and low energy consumption. It is an effective method for preparing boiling chlorination furnace charge with high calcium and magnesium type titanium slag at low cost, which is of great significance to ensuring the security of raw material resource supply in my country's titanium industry and promoting the high-quality development of my country's titanium industry. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 This is a process flow chart of Example 1 of the present invention.

[0017] Figure 2 Schematic diagram of the equipment for atomization treatment. DETAILED DESCRIPTION

[0018] The specific embodiments of the present invention are further described below by way of examples, but the specific embodiments of the present invention are not limited to the following examples.

[0019] Example 1 A method for strengthening the removal of impurities from high-calcium-magnesium titanium slag comprises the following steps: (1) The TiO-containing 2 =74.15wt%, CaO=1.42wt%, MgO=2.85wt%, SiO 2=5.34wt%, the remainder is common oxides such as aluminum, manganese, iron, and chromium in the titanium slag. The molten titanium slag is transported to a slag holding bucket with heating and heat preservation functions to keep the slag in a molten state. Oxygen with NaCl is sprayed into the slag for oxidation transformation treatment. The oxygen flow rate is 10m 3 / min•t, time 20min, NaCl addition amount is 2% of slag mass.

[0020] (2) The obtained molten titanium slag is flowed into an atomizer for atomization treatment. A high-speed gas injection system is used to atomize the liquid slag into titanium slag powder particles. Air is used with a gas flow rate of 0.2m 3 / s, the gas pressure is 5MPa, the gas flow rate is 50m / s, the flow rate of the molten titanium slag atomization process is 50kg / min, and the particle size of the titanium slag after atomization is 0.1mm~1mm.

[0021] (3) The transformed titanium slag powder is subjected to a hydrochloric acid leaching process to remove impurities. The hydrochloric acid concentration is 30% (mass percentage concentration), the leaching temperature is 150°C, and the leaching time is 1 hour. The titanium-rich material TiO 2 97.09%, CaO 0.096%, MgO 0.314%. The XRF results of the titanium-rich material product obtained in Example 1 are as follows: .

[0022] Example 2 A method for strengthening the removal of impurities from high-calcium-magnesium titanium slag comprises the following steps: (1) TiO discharged from electric furnace smelting 2 =80.15%, CaO=1.12%, MgO=1.69%, SiO 2 =4.36%, the remainder is common oxides such as aluminum, manganese, iron, and chromium in the titanium slag; the molten titanium slag is transported to a slag holding bucket with heating and heat preservation functions to keep the slag in a molten state, and a mixed gas consisting of 50% oxygen and 50% air with NaCl added is sprayed into the slag for oxidation transformation treatment, with a flow rate of 30m 3 / min•t, time 2min, NaCl addition amount is 1.5% of slag mass.

[0023] (2) The obtained molten titanium slag is flowed into an atomizer for atomization treatment. A high-speed gas injection system is used to atomize the liquid slag into titanium slag powder particles. Oxygen is used with a gas flow rate of 0.5m 3 / s, the gas pressure is 15MPa, the gas flow rate is 500m / s, the flow rate of the molten titanium slag atomization process is 100kg / min, and the particle size of the titanium slag after atomization is 0.1m~1mm.

[0024] (3) The transformed titanium slag powder is subjected to a hydrochloric acid leaching process to remove impurities. The hydrochloric acid concentration is 20%, the leaching temperature is 140°C, and the leaching time is 2 hours. The titanium-rich material TiO 2 93.36%, CaO 0.06%, MgO 0.37%.

[0025] Example 3 A method for strengthening the removal of impurities from high-calcium-magnesium titanium slag comprises the following steps: (1) The TiO-containing 2 =77.15%, CaO=1.24%, MgO=1.98%, SiO 2 =4.58%, the remainder is common oxides such as aluminum, manganese, iron, and chromium in titanium slag; the molten titanium slag is transported to a slag holding bucket with heating and heat preservation functions to keep the slag in a molten state, and oxygen with NaCl is sprayed into the slag for oxidation transformation treatment, with a flow rate of 20m 3 / min•t, time 10min, NaCl addition amount is 1.0% of slag mass.

[0026] (2) The obtained molten titanium slag is flowed into an atomizer for atomization treatment. A high-speed gas injection system is used to atomize the liquid slag into titanium slag powder particles. Water vapor is used with a gas flow rate of 0.05m 3 / s, the gas pressure is 1MPa, the gas flow rate is 20m / s, the flow rate of the molten titanium slag atomization process is 5kg / min, and the particle size of the titanium slag after atomization is 0.1mm~1mm.

[0027] (3) The transformed titanium slag powder was subjected to a hydrochloric acid leaching process to remove impurities. The hydrochloric acid concentration was 15%, the leaching temperature was 120 °C, and the leaching time was 4 hours. The titanium-rich material TiO 2 93.12%, CaO 0.11%, MgO 0.45%.

[0028] Example 4 Other conditions are the same as those in Example 1, except that: (1) The TiO-containing 2 =74.15wt%, CaO=1.42wt%, MgO=2.85wt%, SiO 2 =5.34wt%, the remainder is common oxides such as aluminum, manganese, iron, and chromium in titanium slag; the molten titanium slag is transported to a slag holding bucket with heating and heat preservation functions to keep the slag in a molten state, and oxygen with NaCl is sprayed into the slag for oxidation transformation treatment, with a flow rate of 2m 3 / min•t, time 30min, NaCl addition amount is 1.5% of slag mass.

[0029] (2) The obtained molten titanium slag is flowed into an atomizer for atomization treatment. A high-speed gas injection system is used to atomize the liquid slag into titanium slag powder particles. Air is used with a gas flow rate of 0.1m 3 / s, the gas pressure is 1MPa, the gas flow rate is 20m / s, the flow rate of the molten titanium slag atomization process is 50kg / min, and the particle size of the titanium slag after atomization is 0.1mm~1mm.

[0030] (3) The titanium slag powder after transformation was subjected to a hydrochloric acid leaching process to remove impurities. The hydrochloric acid concentration was 30% (mass percentage concentration), the leaching temperature was 150°C, and the leaching time was 1 hour. The titanium-rich material TiO 2 93.22%, CaO 0.11%, MgO 0.46%.

[0031] Example 5 Other conditions are the same as those in Example 1, except that: (1) The TiO-containing 2 =74.15wt%, CaO=1.42wt%, MgO=2.85wt%, SiO 2 =5.34wt%, the remainder is common oxides such as aluminum, manganese, iron, and chromium in titanium slag; the molten titanium slag is transported to a slag holding bucket with heating and heat preservation functions to keep the slag in a molten state, and oxygen is sprayed into the slag for oxidation transformation treatment. The flow rate is 30m 3 / min•t, time 3min; the amount of NaCl added is 0.5% of the slag mass.

[0032] (2) The obtained molten titanium slag is flowed into an atomizer for atomization treatment. A high-speed gas injection system is used to atomize the liquid slag into titanium slag powder particles. Air is used with a gas flow rate of 0.2m 3 / s, the gas pressure is 5MPa, the gas flow rate is 50m / s, the flow rate of the molten titanium slag atomization process is 50kg / min, and the particle size of the titanium slag after atomization is 0.1mm~1mm.

[0033] (3) The transformed titanium slag powder is subjected to a hydrochloric acid leaching process to remove impurities. The hydrochloric acid concentration is 30% (mass percentage concentration), the leaching temperature is 150°C, and the leaching time is 1 hour. The titanium-rich material TiO 2 92.58%, CaO 0.15%, MgO 0.79%.

[0034] Example 6 Other conditions are the same as those in Example 1, except that: (1) The TiO-containing 2=74.15wt%, CaO=1.42wt%, MgO=2.85wt%, SiO 2 =5.34wt%, the remainder is common oxides such as aluminum, manganese, iron, and chromium in the titanium slag. The molten titanium slag is transported to a slag holding bucket with heating and heat preservation functions to keep the slag in a molten state. Oxygen is sprayed into the slag for oxidation and transformation treatment. The flow rate is 10m 3 / min•t, time 20min, NaCl addition amount is 0.2% of slag mass.

[0035] (2) The obtained molten titanium slag is flowed into an atomizer for atomization treatment. A high-speed gas injection system is used to atomize the liquid slag into titanium slag powder particles. Air is used with a gas flow rate of 0.5m 3 / s, the gas pressure is 10MPa, the gas flow rate is 100m / s, the flow rate of the molten titanium slag atomization process is 50kg / min, and the particle size of the titanium slag after atomization is 0.1mm~1mm.

[0036] (3) The transformed titanium slag powder is subjected to a hydrochloric acid leaching process to remove impurities. The hydrochloric acid concentration is 30% (mass percentage concentration), the leaching temperature is 150°C, and the leaching time is 1 hour. The titanium-rich material TiO 2 94.10%, CaO 0.13%, MgO 0.65%.

[0037] Comparative Example 1 A method for strengthening the removal of impurities from high-calcium-magnesium titanium slag comprises the following steps: Step (3) is the same as that in Example 1, except that: the TiO-containing 2 =74.15%, CaO=1.42%, MgO=2.85%, SiO 2 =5.34% molten titanium slag is naturally cooled and crushed to less than -1mm, and then oxidized and roasted in a rotary kiln at a temperature of 1000°C for 2 hours; The transformed titanium slag powder was subjected to a hydrochloric acid leaching process to remove impurities. The hydrochloric acid concentration was 30%, the leaching temperature was 150°C, and the leaching time was 1 hour. The titanium-rich material TiO 2 82.23%, CaO 0.67%, MgO 1.65%, SiO 2 =5.22%, which cannot meet the boiling chlorination requirements.

[0038] Comparative Example 2 A method for strengthening the removal of impurities from high-calcium-magnesium titanium slag comprises the following steps: Step (3) is consistent with Example 1, except that: NaCl is not added in step (1), and in step (2), the molten titanium slag obtained is naturally cooled and crushed to -1 mm, and then acid leaching is performed to remove impurities.

[0039] The transformed titanium slag powder was subjected to a hydrochloric acid leaching process to remove impurities. The hydrochloric acid concentration was 30%, the leaching temperature was 150°C, and the leaching time was 1 hour. The titanium-rich material TiO 2 83.46%, CaO 0.59%, MgO 1.42%, SiO 2 =5.15%, which cannot meet the boiling chlorination requirements.

[0040] The above is only a preferred embodiment of the present invention, and the protection scope of the present invention is not limited to the above embodiments. For those skilled in the art, improvements and changes obtained without departing from the technical concept of the present invention should also be regarded as the protection scope of the present invention.

Claims

1. A method for strengthening the removal of impurities from high calcium and magnesium type titanium slag, characterized in that: The following steps are involved: S1 transports the molten titanium slag from the electric furnace smelting process of ilmenite concentrate to a slag holding bucket with heating and heat preservation functions to keep the slag flowing, and injects gas with NaCl into the slag for oxidation transformation treatment; the injection gas flow rate is 2~30m 3 / min•tslag; S2: The molten titanium slag obtained in step 1 flows into the atomizer for atomization treatment, and a high-speed gas injection system is used to atomize the molten titanium slag into titanium slag powder particles; during the atomization treatment, the gas flow rate is 0.05~0.5m 3 / s, gas pressure is 0.5~15MPa, gas flow rate is 20~500m / s; S3 uses a hydrochloric acid leaching process to remove impurities from the transformed titanium slag powder to obtain titanium-rich material that meets the boiling chlorination requirements.

2. The method for removing impurities from enhanced high calcium and magnesium titanium slag according to claim 1, characterized in that: The titanium slag in step S1 contains TiO2≥70wt%.

3. The method for strengthening the transformation and removal of impurities of high calcium magnesium titanium slag according to claim 1, characterized in that: In the step S1, the gas sprayed into the molten titanium slag in the slag holding bucket includes one or more of oxygen, air, etc., the spraying time is 2-30 minutes, and the mass of the sprayed NaCl is controlled to be 0.2-2% of the slag.

4. The method for removing impurities from enhanced high calcium and magnesium titanium slag according to claim 1, characterized in that: In step S2, the gas used includes one or more of water vapor, oxygen, air, etc.

5. The method for removing impurities from enhanced high calcium and magnesium titanium slag according to claim 1, characterized in that: The flow rate of the molten titanium slag atomization process in step S2 is 1-100 kg / min.

6. The method for strengthening the transformation and removal of impurities of high calcium and magnesium type titanium slag according to claim 1 is characterized in that: The particle size of the titanium slag after atomization in step S2 is 0.1 mm to 1 mm.

7. The method for removing impurities from enhanced high calcium and magnesium titanium slag according to claim 1, characterized in that: In the hydrochloric acid leaching process in step S3, the hydrochloric acid concentration is 15-30%, the leaching temperature is 120-150° C., and the time is 1-4 hours.

8. The method for removing impurities from enhanced high calcium and magnesium titanium slag according to claim 1, characterized in that: The titanium-rich material obtained in step S3 has TiO2≥85%, CaO≤0.2%, MgO≤1.0%, and other indicators meet the requirements of boiling chlorination.

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