Method for strengthening high calcium magnesium type titanium slag to remove impurities

Abstract

The application discloses a method for removing impurities from reinforced high-calcium and high-magnesium titanium slag, which comprises the following steps: S1, during the process of smelting slag from ilmenite concentrate electric furnace, spraying gas with added NaCl into the molten titanium slag for oxidation transformation treatment; S2, flowing the molten titanium slag obtained in step 1 into an atomizer for atomization treatment, further promoting the transformation of the titanium slag, and crushing the titanium slag into powder particles; S3, removing impurities from the transformed titanium slag powder by using one-stage hydrochloric acid leaching process, so that the titanium-rich material meeting the requirements of boiling chlorination can be obtained. The method for removing impurities from reinforced high-calcium and high-magnesium titanium slag can be connected with the existing titanium slag production process, fully utilize the heat of the molten titanium slag, realize the rapid transformation of the titanium slag, crush the titanium slag into powder particles, adopt one-stage leaching for acid leaching and impurity removal of the transformed titanium slag, and has the advantages of short process, low energy consumption, and the like, so that the high-calcium and high-magnesium titanium slag can be prepared into boiling chlorination furnace material at low cost, and the method has important significance for guaranteeing the safety of raw material resource supply of the titanium industry in China and promoting the high-quality development of the titanium industry in China.

Description

TECHNICAL FIELD

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

[0002] There are mainly two methods for industrial production of titanium dioxide, i.e. chlorination method and sulfuric acid method. The product quality of titanium dioxide prepared by the chlorination method is superior to that prepared by the sulfuric acid method, so the chlorination method dominates the development trend of the titanium dioxide industry. However, the boiling chlorination method has strict requirements on the quality of the titanium-containing raw material, and the boiling chlorination furnace charge needs to meet the requirements of TiO2 content > 85%, CaO content < 0.35%, and MgO content < 1.0%.

[0003] The electric furnace titanium slag obtained by smelting of high calcium and magnesium ilmenite concentrate in an electric furnace has high calcium and magnesium content, and is difficult to be directly used as a boiling chlorination furnace charge to produce chlorination method titanium dioxide and titanium sponge. At present, the technical route mainly adopted for the research on removal of impurities from the titanium slag to prepare the boiling chlorination furnace charge is to convert titanium in the titanium slag into rutile which is difficult to be dissolved, and convert impurity elements into mineral phases which are easy to be dissolved, so as to achieve the purpose of selective removal of impurities and enrichment of titanium. There are mainly two methods. One is to add additives such as sulfur dioxide, phosphoric acid, sodium base or sodium salt, and phosphate salt for roasting treatment, and then perform acid leaching to remove impurities. The additives are difficult to be recycled, which not only increases the production cost, but also may affect the product quality. The other is to perform two-stage transformation treatment of the titanium slag by oxidation roasting and reduction roasting, and then perform two-stage acid leaching to remove impurities, such as the UGS slag preparation process of QIT Company in Canada, which has problems of high energy consumption and long process.

[0004] Therefore, in view of the above problems existing in the removal of impurities from the high calcium and magnesium type titanium slag to prepare the boiling chlorination furnace charge, the purpose of the present application is to provide a method for strengthening removal of impurities from high calcium and magnesium type titanium slag, which is directly applied to the existing titanium slag production process to perform transformation and crushing treatment on the liquid furnace slag, so as to shorten the process, reduce the energy consumption, reduce the cost of removal of impurities from the titanium slag, and promote the sustainable development of the titanium industry in China. SUMMARY

[0005] The present application provides the following technical scheme: a method for strengthening transformation and removal of impurities from titanium slag, comprising the following steps:

[0006] S1: conveying the molten titanium slag obtained by smelting of ilmenite concentrate by an electric furnace to a slag holding bucket with heating and heat preservation functions, so that the molten slag remains in a flowing state, and spraying a gas with added NaCl into the molten slag to perform oxidation transformation treatment;

[0007] S2: flowing the molten titanium slag obtained in step 1 into an atomizer to perform atomization treatment, and using a high-speed gas blowing system to atomize the liquid slag into titanium slag powder particles;

[0008] S3 The transformed titanium slag powder is treated by one-stage hydrochloric acid leaching process to remove impurities, and a titanium-rich material meeting the requirements of boiling chlorination can be obtained.

[0009] Preferably, the TiO2 content in the titanium slag of step S1 is ≥70wt%.

[0010] Preferably, in step S1, the injected gas includes one or more of oxygen, air, etc., and the gas flow rate is 2-30m 3 / min•t slag, preferably 5-15m 3 / min•t slag, and the injection time is 2-30min. In step S1 of the present application, the gas is preferably oxygen-rich gas for oxidation transformation treatment, the purpose of which is to oxidize low-valence titanium in the slag to rutile TiO2, and the purpose of adding NaCl is to improve the dissolution activity of impurities in the slag, thereby providing favorable conditions for subsequent selective impurity removal by acid leaching.

[0011] Preferably, in step S1, the amount of NaCl injected is controlled to be 0.2-2.5% of the slag, preferably 0.5-2.1%, and further preferably 1.5-2.1%. This includes a series of schemes such as 2.0%, 1.9-2.1%, 1.8-2.05%, etc.

[0012] Preferably, in step S2, the high-speed gas includes one or more of water vapor, oxygen, air, etc., and the gas flow rate is 0.05-0.5m 3 / s, the gas pressure is 0.5-15MPa, and the gas flow rate is 20-500m / s. In the present application, the 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, the gas pressure is 0.5-15MPa, and the gas flow rate is 20-500m / s, which is to provide a certain cooling intensity to keep the silicates in the slag in a disintegrated state and not form stable crystal structures, while achieving the purpose of breaking.

[0013] Preferably, in step S2, the flow rate during the atomization of the molten titanium slag is 1-100kg / min, preferably 30-60kg / min.

[0014] Preferably, in step S2, the particle size of the titanium slag after atomization is 0.1mm-1mm.

[0015] Preferably, in step S3, the one-stage hydrochloric acid leaching process uses hydrochloric acid with a concentration of 15-30wt%, the leaching temperature is 120-150℃, and the leaching time is 1-4 hours. In the present application, the use of 15-30wt% hydrochloric acid at 120-150℃ has the advantages of good selectivity for impurity removal and high impurity removal rate.

[0016] Preferably, the step S3 obtains the titanium-rich material TiO2≥85%, CaO≤0.2%, MgO≤1.0%, and other related indexes meet the requirements of boiling chlorination.

[0017] The present application has the advantages of:

[0018] In view of the problems of high energy consumption, long process and environment of various methods for preparing boiling chlorination furnace charge from titanium slag, the present application provides a method for strengthening removal of impurities from high calcium and magnesium type titanium slag, which connects the existing titanium slag production process, fully utilizes the heat of molten titanium slag, realizes rapid transformation of titanium slag, improves the dissolution activity of impurities, and breaks the titanium slag into powder particles, and the transformed titanium slag is subjected to one-stage leaching and impurity removal by hydrochloric acid leaching, NaCl added in the process is dissolved out during acid leaching, can be recycled and reused, and has the advantages of short process and low energy consumption, and is an effective method for preparing boiling chlorination furnace charge from high calcium and magnesium type titanium slag at low cost, which is of great significance to guarantee the safety of raw material resource supply of titanium industry in China and promote the high-quality development of titanium industry in China. BRIEF DESCRIPTION OF DRAWINGS

[0019] Figure 1 The process flow diagram of Example 1 of the present application.

[0020] Figure 2 The schematic diagram of the equipment for the atomization treatment. DETAILED DESCRIPTION

[0021] The specific embodiments of the present application will be further illustrated by the following examples, but the specific embodiments of the present application are not limited to the following examples.

[0022] Example 1

[0023] A method for strengthening removal of impurities from high calcium and magnesium type titanium slag, comprising the following steps:

[0024] (1) The molten titanium slag discharged from the electric furnace smelting contains TiO2=74.15wt%, CaO=1.42wt%, MgO=2.85wt%, SiO2=5.34wt%, and the balance is common oxides such as aluminum, manganese, iron and chromium in titanium slag, the molten titanium slag is conveyed to a slag holding bucket with heating and heat preservation function to keep the molten slag in molten state, and oxygen with added NaCl is sprayed into the slag for oxidation transformation treatment, the oxygen flow is 10m 3 / min•t, the time is 20min, and the added amount of NaCl is 2% of the mass of molten slag.

[0025] (2) The obtained molten titanium slag is flowed into an atomizer for atomization treatment, the liquid slag is atomized into titanium slag powder particles by using a high-speed gas blowing system, and air is used, and the gas flow is 0.2m 3s, the gas flow rate is 50 m / s, the flow rate of the molten titanium slag atomization process is 50 kg / min, and the particle size of the titanium slag after atomization is 0.1 mm-1 mm.

[0026] (3) The transformed titanium slag powder is removed by one-stage hydrochloric acid leaching process, the hydrochloric acid concentration is 30% (mass percentage), the leaching temperature is 150°C, and the time is 1 hour, and the obtained titanium-rich material TiO2 is 97.09%, CaO is 0.096%, and MgO is 0.314%. The XRF results of the titanium-rich material product obtained in Example 1 are as follows: .

[0027] Example 2

[0028] A method for removing impurities from high calcium and magnesium type titanium slag, comprising the following steps:

[0029] (1) The TiO2 content of the titanium slag discharged from the electric furnace smelting is 80.15%, the CaO content is 1.12%, the MgO content is 1.69%, the SiO2 content is 4.36%, and the balance is aluminum, manganese, iron, chromium and other common oxides in the titanium slag; the molten titanium slag is transported to a slag holding bucket with heating and heat preservation function, so that the molten slag remains in a molten state, and a mixed gas composed of 50% oxygen and 50% air with added NaCl is sprayed into the slag for oxidation transformation treatment, the flow rate is 30 m 3 / min•t, the time is 2 min, and the amount of added NaCl is 1.5% of the mass of the molten slag.

[0030] (2) The obtained molten titanium slag is flowed into an atomizer for atomization treatment, a high-speed gas blowing system is used to atomize the liquid slag into titanium slag powder particles, oxygen is used, the gas flow rate is 0.5 m 3 / s, the gas pressure is 15 MPa, the gas flow rate is 500 m / s, the flow rate of the molten titanium slag atomization process is 100 kg / min, and the particle size of the titanium slag after atomization is 0.1 mm-1 mm.

[0031] (3) The transformed titanium slag powder is removed by one-stage hydrochloric acid leaching process, the hydrochloric acid concentration is 20%, the leaching temperature is 140°C, and the time is 2 hours, and the obtained titanium-rich material TiO2 is 93.36%, CaO is 0.06%, and MgO is 0.37%.

[0032] Example 3

[0033] A method for removing impurities from high calcium and magnesium type titanium slag, comprising the following steps:

[0034] (1) The electric furnace smelting discharged Ti02=77.15%, CaO=1.24%, MgO=1.98%, Si02=4.58%, the balance of the common oxides such as aluminum, manganese, iron, chromium in the titanium slag; the molten titanium slag is transported to the slag holding bucket with heating and heat preservation function, so that the molten slag is kept in molten state, and oxygen with added NaCl is sprayed into the slag for oxidation transformation treatment, the flow rate is 20m 3 / min•t, the time is 10 min, and the added amount of NaCl is 1.0% of the mass of the molten slag.

[0035] (2) The obtained molten titanium slag is flowed into an atomizer for atomization treatment, a high-speed gas blowing system is used to atomize the liquid slag into titanium slag powder particles, water vapor is used, the gas flow rate is 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 5 kg / min, and the particle size of the titanium slag after atomization is 0.1mm~1mm.

[0036] (3) The transformed titanium slag powder is removed by one-stage hydrochloric acid leaching process, the hydrochloric acid concentration is 15%, the leaching temperature is 120℃, and the time is 4 hours, and the obtained titanium-rich material Ti02 93.12%, CaO 0.11%, MgO 0.45%.

[0037] Example 4

[0038] Other conditions are the same as those in Example 1, except that:

[0039] (1) The electric furnace smelting discharged Ti02=74.15wt%, CaO=1.42wt%, MgO=2.85wt%, Si02=5.34wt%, the balance of the common oxides such as aluminum, manganese, iron, chromium in the titanium slag; the molten titanium slag is transported to the slag holding bucket with heating and heat preservation function, so that the molten slag is kept in molten state, and oxygen with added NaCl is sprayed into the slag for oxidation transformation treatment, the flow rate is 2m 3 / min•t, the time is 30 min, and the added amount of NaCl is 1.5% of the mass of the molten slag.

[0040] (2) The obtained molten titanium slag is flowed into an atomizer for atomization treatment, a high-speed gas blowing system is used to atomize the liquid slag into titanium slag powder particles, air is used, the gas flow rate is 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.

[0041] (3) The transformed titanium slag powder is removed by one-stage hydrochloric acid leaching process, the concentration of hydrochloric acid is 30% (mass percentage), the leaching temperature is 150°C, and the time is 1 hour, and the obtained titanium-rich material TiO2 is 93.22%, CaO is 0.11%, and MgO is 0.46%.

[0042] Example 5

[0043] The other conditions are consistent with those in Example 1, except that:

[0044] (1) The electric furnace smelting discharged titanium slag containing TiO2=74.15wt%, CaO=1.42wt%, MgO=2.85wt%, SiO2=5.34wt%, and the balance of common oxides such as aluminum, manganese, iron, and chromium in the titanium slag is conveyed to a slag holding bucket with heating and heat preservation function, so that the molten slag remains in a molten state, and oxygen is sprayed into the slag for oxidation transformation treatment, the flow rate is 30m 3 / min•t, the time is 3min, and the amount of NaCl added is 0.5% of the mass of the molten slag.

[0045] (2) The obtained molten titanium slag is flowed into an atomizer for atomization treatment, a high-speed gas blowing system is used to atomize the liquid slag into titanium slag powder particles, air is used, the gas flow rate is 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.

[0046] (3) The transformed titanium slag powder is removed by one-stage hydrochloric acid leaching process, the concentration of hydrochloric acid is 30% (mass percentage), the leaching temperature is 150°C, and the time is 1 hour, and the obtained titanium-rich material TiO2 is 93.22%, CaO is 0.11%, and MgO is 0.46%.

[0047] Example 6

[0048] The other conditions are consistent with those in Example 1, except that:

[0049] (1) The electric furnace smelting discharged titanium slag containing TiO2=74.15wt%, CaO=1.42wt%, MgO=2.85wt%, SiO2=5.34wt%, and the balance of common oxides such as aluminum, manganese, iron, and chromium in the titanium slag is conveyed to a slag holding bucket with heating and heat preservation function, so that the molten slag remains in a molten state, and oxygen is sprayed into the slag for oxidation transformation treatment, the flow rate is 30m 3 / min•t, the time is 3min, and the amount of NaCl added is 0.5% of the mass of the molten slag.

[0050] (2) The obtained molten titanium slag is flowed into an atomizer for atomization treatment, liquid slag is atomized into titanium slag powder particles by using a high-speed gas blowing system, air is used, the gas flow is 0.5 m 3 / s, the gas pressure is 10 MPa, the gas flow rate is 100 m / s, the flow rate of the molten titanium slag atomization process is 50 kg / min, and the particle size of the titanium slag after atomization is 0.1 mm to 1 mm.

[0051] (3) The transformed titanium slag powder is treated by one-stage hydrochloric acid leaching process to remove impurities, the hydrochloric acid concentration is 30% (mass percentage concentration), the leaching temperature is 150 DEG C, and the time is 1 hour, and the obtained titanium-rich material TiO2 is 94.10%, CaO is 0.13%, and MgO is 0.65%.

[0052] Comparative Example 1

[0053] A method for removing impurities from high calcium and magnesium type titanium slag, comprising the following steps:

[0054] Step (3) is consistent with Example 1, except that the molten titanium slag discharged from the electric furnace smelting in Example 1 contains TiO2=74.15%, CaO=1.42%, MgO=2.85%, and SiO2=5.34%, and is naturally cooled and broken to below-1 mm, and is subjected to oxidation roasting transformation by using a rotary kiln, the roasting temperature is 1000 DEG C, and the time is 2 hours.

[0055] The transformed titanium slag powder is treated by one-stage hydrochloric acid leaching process to remove impurities, the hydrochloric acid concentration is 30%, the leaching temperature is 150 DEG C, and the time is 1 hour, and the obtained titanium-rich material TiO2 is 82.23%, CaO is 0.67%, MgO is 1.65%, and SiO2=5.22%, which cannot meet the requirements of boiling chlorination.

[0056] Comparative Example 2

[0057] A method for removing impurities from high calcium and magnesium type titanium slag, comprising the following steps:

[0058] Step (3) is consistent with Example 1, except that NaCl is not added in step (1), and the obtained molten titanium slag is naturally cooled and broken to-1 mm before being subjected to acid leaching for impurity removal.

[0059] The transformed titanium slag powder is treated by one-stage hydrochloric acid leaching process to remove impurities, the hydrochloric acid concentration is 30%, the leaching temperature is 150 DEG C, and the time is 1 hour, and the obtained titanium-rich material TiO2 is 82.23%, CaO is 0.67%, MgO is 1.65%, and SiO2=5.22%, which cannot meet the requirements of boiling chlorination.

[0060] The above merely describes the preferred embodiments of the present application, and the protection scope of the present application is not limited to the above-described embodiments. Improvements and changes made by those skilled in the art without departing from the technical concept of the present application should also be considered as falling within the protection scope of the present application.

Claims

1. A method for removing impurities from a reinforced high calcium magnesium type titanium slag, characterized in that, The method comprises the following steps: S1 sends the molten titanium slag of the ilmenite concentrate electric furnace smelting process to a slag holding bucket with heating and holding functions, keeps the molten slag in a flowing state, sprays the molten slag with a gas with added NaCl to perform oxidation transformation treatment; the flow rate of the sprayed gas is 2~30 m 3 / min•t slag; S2 flows the molten titanium slag obtained in step 1 into an atomizer for atomization treatment, and uses a high-speed gas blowing system to atomize the molten titanium slag into titanium slag powder particles; during the atomization treatment, the gas flow is 0.05~0.5m / s, the gas pressure is 0.5~15MPa, and the gas flow rate is 20~500m / s. 3 / s, the gas pressure is 0.5~15MPa, and the gas flow rate is 20~500m / s. S3: removing impurities from the transformed titanium slag powder by one-stage hydrochloric acid leaching process to obtain a titanium-rich material meeting the requirements of boiling chlorination.

2. The method for removing impurities from the reinforced high calcium and magnesium type titanium slag according to claim 1, characterized in that, The TiO2 content in the titanium slag of step S1 is ≥ 70 wt%.

3. The method according to claim 1, wherein the method is characterized by, In step S1, the gas sprayed into the molten titanium slag in the slag ladle includes one or more of oxygen and air, the spraying time is 2-30 min, and the mass of the sprayed NaCl is controlled at 0.2-2% of the slag.

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

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

6. The method according to claim 1, wherein the method is characterized by, In step S2, the particle size of the atomized titanium slag is 0.1-1 mm.

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

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