Seed crystal and method for promoting increase of titanium component in titanium-containing blast furnace slag

Abstract

The invention discloses a seed crystal and a method for promoting increase of a titanium component in titanium-containing blast furnace slag, and belongs to the technical field of metallurgy. The seed crystal for promoting the increase of the titanium component in the titanium-containing blast furnace slag comprises carbon powder and ilmenite, and the mass ratio of the carbon powder to the ilmenite is 3-9%. According to the method for promoting the increase of the titanium component in the titanium-containing blast furnace slag, air serves as a carrier, any seed crystal in the claims is added into the molten titanium-containing blast furnace slag at the temperature of 1390-1410 DEG C, the added seed crystal is subjected to heat preservation for 5-10 min at the temperature of 1090-1110 DEG C, and the adding amount of the seed crystal accounts for 3-20% of the mass of the titanium-containing blast furnace slag. The seed crystal can promote crystal grains of a titanium component mineral phase in the titanium-containing blast furnace slag to be rapidly increased, increase of the titanium component in the titanium-containing blast furnace slag can be more effectively promoted by controlling the adding amount, and concentrate with appropriate granularity is provided for follow-up flotation.

Description

Technical Field

[0001] The invention discloses a crystal seed and a method for promoting the increase of titanium components in titanium-containing blast furnace slag, belonging to the technical field of metallurgy. Background Art

[0002] Titanium-containing blast furnace slag is a type of solid waste from the steel industry, and its comprehensive utilization as a resource has always been a hot topic and difficulty in research. Titanium-containing blast furnace slag is rich in titanium (the highest titanium dioxide content is 25%), and titanium is a valuable chemical element with a wide range of applications, such as in coatings, cosmetics, pharmaceuticals, and alloys. However, since the titanium component exists in the form of several microns in the titanium-containing blast furnace slag, it is difficult to effectively extract the titanium from the titanium-containing blast furnace slag. Currently, the Panzhihua area discharges millions of tons of titanium-containing blast furnace slag each year, and nearly 100 million tons of slag have accumulated over the past few decades, which urgently needs to be treated.

[0003] At present, the research process of comprehensive utilization of titanium-containing blast furnace slag is mainly divided into wet method and pyrolysis method. The wet method mainly includes sulfuric acid method, ammonium sulfate-ammonia precipitation method and hydrochloric acid method, etc. These methods have their own advantages and disadvantages. For example, although the sulfuric acid method can produce titanium dioxide, the cost is relatively high, and the waste acid and green vitriol produced are still a world-class problem. The ammonium sulfate-ammonia precipitation method can improve the purity of titanium dioxide, but ammonia will volatilize during the process, which may cause air pollution. Although the hydrochloric acid method has achieved some results in extracting titanium, it also faces environmental and cost challenges.

[0004] The research progress of pyrometallurgical titanium extraction technology from titanium-containing blast furnace slag mainly focuses on the following aspects:

[0005] Carbonization method: Through a high-temperature carbonization process, the titanium element in the titanium-containing blast furnace slag is converted into titanium carbide (TiC), and then titanium is extracted through a subsequent acid leaching or alkali leaching process; Sodiumization method: Sodium is used as a reducing agent to react with titanium oxide in the titanium-containing blast furnace slag at high temperature to generate soluble sodium titanium salts, and then titanium is extracted; Molten salt method: Titanium is extracted by electrolysis or chemical reduction in a high-temperature molten salt environment. This method can achieve titanium extraction with lower energy consumption; Aluminothermic method: Aluminum is used as a reducing agent to reduce titanium oxide in titanium-containing blast furnace slag at high temperature to generate metallic titanium or its alloy; High-temperature chlorination: Through a high-temperature chlorination process, titanium oxide in the titanium-containing blast furnace slag is converted into gaseous or liquid titanium chloride, and then titanium is recovered by condensation or absorption.

[0006] These pyrometallurgical technologies each have their own advantages and limitations. For example, the carburization method and the sodium method are more efficient in extracting titanium, but may produce harmful by-products; while the molten salt method and the thermite method may have lower energy consumption and environmental impact, but the technology is more difficult to implement.

[0007] Some researchers have proposed to achieve low energy consumption and high recovery rate of titanium components by controlling the growth of titanium group grains of several microns in titanium-containing blast furnace slag and then flotation. The basic idea of ​​this method is: according to the TiO 2 Minerals with high TiO content have the characteristics of high crystallization temperature. By adding silicon dioxide and calcium oxide to adjust the slag composition and other conditions, a TiO-containing 2 The higher minerals crystallize and grow, and then they are separated; the separated high-titanium minerals can be used as titanium-rich resources, and the blast furnace slag after titanium reduction can be used to produce cement. Although the research results of this method can achieve titanium extraction to a certain extent, the grains of the generated titanium minerals are only 30 microns, which is difficult to recover through mineral processing and flotation. The comprehensive resource utilization of titanium-containing blast furnace slag requires comprehensive consideration of the feasibility, environmental protection, economy and sustainability of the production process.

[0008] Therefore, the most effective and economical method for treating titanium-containing blast furnace slag is to separate it by combining mineral processing and metallurgy. At present, the particle size of the perovskite mineral phase in titanium-containing blast furnace slag is only a few microns, which brings difficulties to mineral processing and separation. Therefore, how to solve the problem of the fine particle size of the titanium component in titanium-containing blast furnace slag is the key. Summary of the invention

[0009] The technical problem to be solved by the present invention is that the current treatment of titanium-containing blast furnace slag adopts a mineral separation-metallurgy combined process for separation, but the perovskite mineral phase in the titanium-containing blast furnace slag has a fine particle size, which makes mineral separation difficult.

[0010] The technical solution adopted by the present invention to solve the technical problem is: the seed crystals for promoting the increase of titanium component in titanium-containing blast furnace slag include ilmenite and carbon powder, and the mass ratio of the carbon powder to the ilmenite is 3-9%.

[0011] The particle size of the ilmenite is 70 to 80 microns, and the grade is 45 to 55%.

[0012] Wherein, the particle size of the ilmenite and carbon powder after mixing is less than or equal to 200 meshes.

[0013] A method for promoting the increase of titanium components in titanium-containing blast furnace slag, using air as a carrier, adding any of the above-mentioned seeds to the molten titanium-containing blast furnace slag at 1390°C to 1410°C, and the added seeds are kept warm at 1090°C to 1110°C for 5 to 10 minutes, and the amount of seeds added is 3 to 20% of the mass of the titanium-containing blast furnace slag.

[0014] Wherein, the amount of seed crystal added in the above method is 6-10% of the mass of the titanium-containing blast furnace slag.

[0015] Wherein, in the chemical composition of the titanium-containing blast furnace slag in the above method, the titanium oxide content is 7-25% by mass.

[0016] Furthermore, the temperature of the molten titanium-containing blast furnace slag in the above method is 1400°C.

[0017] Furthermore, the molten titanium-containing blast furnace slag at 1400°C in the above method is obtained by cooling the molten titanium-containing blast furnace slag at 1450°C to 1470°C at an average rate of 1.5 to 3°C / min.

[0018] In the above method, after adding seed crystals to the titanium-containing blast furnace slag, the temperature is lowered to room temperature at an average rate of 1.5 to 3°C / min.

[0019] Furthermore, in the above method, after adding seed crystals to the titanium-containing blast furnace slag, the temperature is lowered to room temperature at an average rate of 2 to 2.5°C / min.

[0020] The beneficial effects of the present invention are as follows: the present solution uses ilmenite with a rutile layer on the surface after weak reduction as a seed crystal, adds the seed crystal of the present invention to the molten titanium-containing blast furnace slag at 1400°C, and controls the amount of addition and the cooling rate, so that the titanium component dispersed in the blast furnace slag can be crystallized and increased nearby, and the obtained well-crystallized titanium component can be well extracted by flotation or gravity separation. And the present method further limits the amount of seed crystal addition and the cooling rate, which can further promote the rapid increase of the titanium component, and is conducive to the recovery of fine-grained ilmenite in the titanium-containing blast furnace slag. The present solution can directly process the titanium-containing blast furnace slag released on-site in the blast furnace, and the process is simple and the cost is low. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 This is a schematic diagram of the microscopic morphology of titanium-containing blast furnace slag after modification by adding seed crystals according to the present invention;

[0022] Figure 2 This is a schematic diagram of the microscopic morphology of titanium-containing blast furnace slag without added seed crystals in the present invention. DETAILED DESCRIPTION

[0023] The present invention is further described below in conjunction with the accompanying drawings and embodiments.

[0024] like Figure 1 and Figure 2 As shown, the seed crystals for promoting the increase of the titanium component in the titanium-containing blast furnace slag of the present invention include carbon powder and ilmenite, and the mass ratio of the carbon powder to the ilmenite is 3-9%. It can be understood by those skilled in the art that in order to promote the increase of the titanium component in the titanium-containing blast furnace slag and facilitate the subsequent ore dressing and titanium extraction, the present scheme preferably adopts the method of mixing ilmenite and carbon powder to prepare the seed crystals, because too high a carbon powder content will lead to over-reduction, and too low a carbon powder content will lead to poor reduction effect, so the mass ratio of the carbon powder to the ilmenite is preferably 3-9%.

[0025] Preferably, the particle size of the ilmenite is 70 to 80 microns and the grade is 45 to 55%. Those skilled in the art will appreciate that the chemical formula of the ilmenite is FeTiO 3 , which can also be expressed as FeO·TiO 2 , its theoretical titanium content (in terms of TiO 2 The ilmenite grade is 52.66% (calculated). In order to ensure the purity of the seed crystal, the grade of ilmenite is improved as much as possible through ore dressing. The grade selected by the best technology at present is 50%. Therefore, in order to ensure the titanium extraction effect, the particle size and grade of ilmenite are preferably selected in this scheme, specifically the particle size is 70-80 microns and the grade is 45-55%. The actual particle size of ilmenite that can be preferred is 74 microns and the grade is 50%.

[0026] Preferably, the particle size of the ilmenite and carbon powder after mixing is less than or equal to 200 mesh. It can be understood by those skilled in the art that in order to enrich the titanium component on the surface of the seed crystal as quickly as possible, the particle size of the ilmenite and carbon powder after mixing, that is, the seed crystal, is less than or equal to 200 mesh. In practice, the particle size of the ilmenite and carbon powder after mixing can preferably be 200 mesh. Since ilmenite is mainly obtained by gravity separation or flotation to obtain titanium concentrate, only flotation can be achieved to obtain high-grade ilmenite concentrate at present. Flotation has requirements for the particle size of ilmenite. Too coarse particle size will cause the flotation foam to be unable to capture the ilmenite mineral. 200 mesh (74 microns) is the particle size of the ilmenite obtained by flotation. In addition, the titanium component mineral obtained by the seed crystal method also needs to be recovered by the mineral processing method. If the particle size is too small, it is not conducive to the recovery of mineral processing.

[0027] The method for promoting the increase of the titanium component in the titanium-containing blast furnace slag is to use air as a carrier, add any of the above-mentioned seeds to the molten titanium-containing blast furnace slag at 1390°C to 1410°C, and keep the added seeds at 1090°C to 1110°C for 5 to 10 minutes, and the amount of seeds added is 3 to 20% of the mass of the titanium-containing blast furnace slag. It can be understood by those skilled in the art that in order to ensure the increase of the titanium component in the titanium-containing blast furnace slag, the method preferably uses air as a carrier and adds any of the above-mentioned seeds to the molten titanium-containing blast furnace slag at 1390°C to 1410°C. In order to further promote the increase of the titanium ore phase in the titanium-containing blast furnace slag, the amount of seeds added in the above method is 3 to 20% of the mass of the titanium-containing blast furnace slag. In order to make the performance of the seed crystal better, carbon powder is added to ilmenite at a mass ratio of 3 to 9% based on the mass of the seed crystal, and the mixture of ilmenite and carbon powder is kept at 1100°C for 5 to 10 minutes. The ilmenite surface can be reduced to generate rutile phase on the surface of the ilmenite for use as a seed crystal, and over-reduction can be prevented for too long a time to generate titanium carbide and nitride.

[0028] Preferably, the amount of seed crystals added in the above method is 6-10% of the mass of the titanium-containing blast furnace slag. It can be understood by those skilled in the art that, since the amount less than 6% cannot ensure that the seed crystals are fully dispersed in the slag according to the minimum density in the titanium-containing blast furnace slag, the density is too low to fully capture the surrounding titanium components, resulting in most of the titanium components being unable to quickly diffuse to the surface of the seed crystals for crystallization. Therefore, in order to further promote the increase of the titanium ore phase in the titanium-containing blast furnace slag, the amount of seed crystals added is preferably 6-10% of the mass of the titanium-containing blast furnace slag.

[0029] Preferably, the titanium oxide content in the chemical composition of the titanium-containing blast furnace slag in the above method is 7-25% by mass. It can be understood by those skilled in the art that since the maximum content of titanium dioxide in the titanium-containing blast furnace slag is currently 25%, there is no economic value in extracting a content lower than 7%. In order to facilitate the processing of more titanium-containing blast furnace slag, the titanium oxide content in the chemical composition of the titanium-containing blast furnace slag processed by this method is 7-25% by mass.

[0030] Preferably, the temperature of the molten titanium-containing blast furnace slag in the above method is 1400° C. Those skilled in the art will appreciate that the present method further preferably sets the temperature of the molten titanium-containing blast furnace slag to 1400° C. to ensure the combination with the seed crystals, so that the titanium component dispersed in the blast furnace slag can be crystallized and enlarged nearby, and the obtained well-crystallized titanium component can be well extracted by flotation or gravity separation.

[0031] Preferably, in the above method, the molten titanium-containing blast furnace slag at 1400°C is obtained by cooling the molten titanium-containing blast furnace slag at 1450°C to 1470°C at an average rate of 1.5 to 3°C / min. It can be understood by those skilled in the art that in order to further promote the increase of the titanium ore phase in the titanium-containing blast furnace slag, after adding seed crystals to the titanium-containing blast furnace slag in the above method, the temperature is cooled to room temperature at an average rate of 1.5 to 3°C / min. At the same time, it is further defined that the molten titanium-containing blast furnace slag at 1400°C is obtained by cooling the molten titanium-containing blast furnace slag at 1450°C to 1470°C. And 1400°C is very close to the crystallization temperature of the minerals in the titanium-containing blast furnace slag. Considering that the control in production cannot be very precise, starting to cool down at 50 to 70°C higher than 1400°C is convenient for production control.

[0032] Preferably, in the above method, after adding seed crystals to the titanium-containing blast furnace slag, the temperature is cooled to room temperature at an average rate of 1.5 to 3°C / min. It can be understood by those skilled in the art that if the cooling rate is too fast, it will not give the nearby titanium components enough time to diffuse to the crystal nucleus, resulting in insufficient time for grain growth and small grains; if the rate is too low, it will affect production and the processing volume per unit time is too low. Therefore, in order to ensure the promotion of the increase of the titanium ore phase in the titanium-containing blast furnace slag, the present method actually preferably adds seed crystals to the titanium-containing blast furnace slag and then cools it to room temperature at an average rate of 1.5 to 3°C / min.

[0033] Preferably, in the above method, after adding seed crystals to the titanium-containing blast furnace slag, the temperature is lowered to room temperature at an average rate of 2 to 2.5°C / min. It can be understood by those skilled in the art that the present method further preferably adds seed crystals to the titanium-containing blast furnace slag, and then cools to room temperature at an average rate of 2 to 2.5°C / min to ensure that the increase of the titanium ore phase in the titanium-containing blast furnace slag is promoted.

[0034] Embodiment 1

[0035] Weigh 500g of titanium-containing blast furnace slag, put it in a graphite crucible, heat and melt it to 1460℃, keep it warm for a period of time, then control the cooling rate to be about 3℃ / min on average. When the slag temperature is about 1400℃, use neutral gas to spray 30g of ilmenite and carbon powder mixture kept at 1100℃ for 5-10min into the slag, control the cooling rate to be about 2℃ / min on average, and cool it to room temperature with the furnace, which can promote the increase of titanium component.

[0036] Embodiment 2

[0037] Weigh 500g of titanium-containing blast furnace slag, put it in a slag pot, heat and melt it to 1460℃, keep it warm for a period of time, then control the cooling rate to be about 3℃ / min on average. When the slag temperature reaches 1410℃, keep it constant, and spray 35g of ilmenite and carbon powder mixture kept at 1100℃ for 5-10min in a molten state. Control the cooling rate to be about 2℃ / mn on average, and cool it to room temperature with the furnace to promote the increase of the titanium component.

[0038] Embodiment 3

[0039] Weigh 500g of titanium-containing blast furnace slag, put it in a slag pot, heat and melt it to raise the temperature to 1470℃. After keeping it warm for a period of time, control the cooling rate to be about 3℃ / min on average. When the slag temperature is 1405℃, keep the temperature constant and spray 30g of ilmenite and carbon powder mixture kept at 1100℃ for 5-10min in the molten state. Control the cooling rate to be about 2℃ / min on average. Cool it to room temperature with the furnace, which can promote the increase of titanium component.

[0040] In the above-mentioned embodiment, the preparation of the seed crystal is to use ilmenite with a particle size of 74 microns and a grade of 50% as the seed crystal, and carbon powder is added to the ilmenite at a mass ratio of 3-9%. The mixture of ilmenite and carbon powder is kept at 1100°C for 5-10 minutes, so that the carbon reduces the iron ions on the surface of the ilmenite, and forms a relatively "clean" rutile layer and other titanium oxide layers on the surface of the ilmenite. Embodiments one, two and three can all promote the increase of the titanium ore phase in the titanium-containing blast furnace slag. The obtained titanium-containing blast furnace slag can be crushed, screened, ground, re-selected or flotated to achieve the recovery of titanium resources. And combined with the attached Figure 1and attached Figure 2 It can be seen that the method can promote the enrichment of titanium components in titanium-containing blast furnace slag on the seed crystals, realize the rapid increase of titanium component grains, thereby facilitating the enrichment and separation of titanium in titanium-containing blast furnace slag, and the equipment is simple and easy to operate. The method can also directly process titanium-containing blast furnace slag immediately released during blast furnace smelting.

Claims

1. A seed crystal for promoting the increase of titanium content in titanium-containing blast furnace slag, characterized in that: The invention comprises carbon powder and ilmenite, wherein the mass ratio of the carbon powder to the ilmenite is 3-9%.

2. The seed crystal for promoting the increase of titanium content in titanium-containing blast furnace slag according to claim 1, characterized in that: The particle size of the ilmenite is 70 to 80 microns, and the grade is 45 to 55%.

3. The seed crystal for promoting the increase of titanium content in titanium-containing blast furnace slag according to claim 1, characterized in that: The particle size of the ilmenite and carbon powder after mixing is less than or equal to 200 meshes.

4. A method for promoting the increase of titanium content in titanium-containing blast furnace slag, characterized in that: The seeds described in any of the above claims are added to the molten titanium-containing blast furnace slag at 1390°C to 1410°C using air as a carrier, and the added seeds are kept at 1090°C to 1110°C for 5 to 10 minutes, and the amount of seeds added is 3 to 20% of the mass of the titanium-containing blast furnace slag.

5. The method for promoting the increase of titanium content in titanium-containing blast furnace slag according to claim 4, characterized in that: The added amount of the seed crystal is 6-10% of the mass of the titanium-containing blast furnace slag.

6. The method for promoting the increase of titanium content in titanium-containing blast furnace slag according to claim 4, characterized in that: The titanium-containing blast furnace slag has a titanium oxide content of 7 to 25% by mass in the chemical composition.

7. The method for promoting the increase of titanium content in titanium-containing blast furnace slag according to claim 4, characterized in that: The temperature of the molten titanium-containing blast furnace slag is 1400°C.

8. The method for promoting the increase of titanium content in titanium-containing blast furnace slag according to claim 7, characterized in that: The molten titanium-containing blast furnace slag at 1400° C. is obtained by cooling the molten titanium-containing blast furnace slag at 1450° C. to 1470° C. at an average speed of 1.5 to 3° C. / min.

9. The method for promoting the increase of titanium content in titanium-containing blast furnace slag according to claim 4, characterized in that: After adding seed crystals to the titanium-containing blast furnace slag, the temperature is lowered to room temperature at an average rate of 1.5 to 3°C / min.

10. The method for promoting the increase of titanium content in titanium-containing blast furnace slag according to claim 9, characterized in that: After adding seed crystals to the titanium-containing blast furnace slag, the temperature is lowered to room temperature at an average rate of 2 to 2.5°C / min.

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