Method for preparing silicon-manganese low-titanium iron by using dust ash of titanium slag smelting furnace

Abstract

This invention discloses a method for preparing ferrosilicon manganese low-titanium ferrophosphate using dust from a titanium slag smelting furnace. The method includes: S1 collecting dust from the titanium slag smelting furnace, spraying atomized water into the rolling dust in a disc granulator to form pellets with a diameter of 15-40 mm, and then feeding them into a shuttle kiln for sintering; S2 stratifying the pellets in the shuttle kiln, cooling, crushing, and screening the top layer of pellets to obtain sintered and crushed dust ash particles, and returning the remainder to the submerged arc furnace; S3 heating the sintered and crushed dust ash particles to above 1550℃ in a medium-frequency furnace, adding aluminum, calcium oxide, and steel, and melting and mixing them; S4 tilting the medium-frequency furnace to discharge slag, then pouring the remaining molten metal into an alloy tank, cooling it to obtain the new material ferrosilicon manganese low-titanium ferrophosphate. This invention provides a low-cost and high-efficiency method for producing ferrosilicon manganese low-titanium ferrophosphate using dust without the need for binders. It converts essentially waste dust into a high-value-added new material, ferrosilicon manganese low-titanium ferrophosphate, while also allowing some dust to be directly sintered into the furnace, resulting in excellent economic benefits.

Description

Technical Field

[0001] This invention belongs to the field of metal smelting waste recycling, specifically a method for preparing ferrosilicon manganese low-titanium iron using dust from titanium slag furnaces. Background Technology

[0002] Titanium slag smelting furnaces smelt titanium-rich raw materials (mainly ilmenite) together with reducing agents (usually anthracite or petroleum coke) to reduce iron oxides to metallic iron and separate them out, thereby obtaining high-grade "titanium slag" (mainly composed of TiO2), which is used as raw material for the subsequent production of titanium dioxide or sponge titanium.

[0003] Dust collector ash is ultrafine dust collected by the dust collection system during the smelting operation of titanium slag smelting furnaces. It mainly consists of titanium ore powder, titanium slag semi-finished product powder, anthracite particles, and anthracite fly ash. Because its titanium dioxide content is 48%-55% (and it contains iron, silicon dioxide, and manganese oxide, etc.), it has reuse value. Currently, most domestic enterprises directly feed it into the furnace. On the one hand, dust collector ash is mostly composed of particles with a size between 300-500 mesh, seriously affecting furnace conditions. On the other hand, the ash is wasted due to secondary waste caused by airborne particles during transport and during charging. Some manufacturers add binders, form pellets, and simply bake them before feeding them into the furnace. The addition of binders leads to an increase in silicon, sodium, or aluminum elements, thus reducing product quality. Furthermore, unsintered pellets will form new dust, further deteriorating furnace conditions. Summary of the Invention

[0004] Based on the above technical problems, in order to fully utilize the dust from the titanium slag furnace without affecting its normal operation, this invention provides a method for preparing ferrosilicon manganese low-titanium ferrophosphate using the dust from the titanium slag furnace. The objective of this invention is achieved through the following technical solution: A method for preparing ferrosilicon manganese low-titanium ferrosilicon using dust from a titanium slag smelting furnace includes the following steps: S1 Pellet Preparation: Collect dust from the titanium slag smelting furnace, spray atomized water into the rolling dust in a disc granulator, control the rotation speed and tilt angle of the disc granulator, roll into pellets with a diameter of 15~40mm, and send the pellets into a shuttle kiln for drying and sintering at a temperature of 900-1200℃ for 1-2 hours. After the S2 sintering is completed, the spheres in the shuttle kiln are layered. The spheres at the top of the shuttle kiln material car in the high-temperature baking part are sent to a designated area for cooling, crushing, and screening to obtain 40-160 mesh sintered crushed dust particles. The remaining spheres are directly sent to the raw material area and fed into the submerged arc furnace to continue smelting titanium slag. S3 uses a medium-frequency furnace to heat the sintered, crushed, and dust-removing ash particles to above 1550°C. Once the material melts, aluminum and calcium oxide are added. The amount of aluminum added accounts for 40% to 60% of the weight of titanium dioxide in the sintered, crushed, and dust-removing ash particles, and the amount of calcium oxide added accounts for 14% to 30% of the weight of aluminum. Then, steel accounting for 20% of the total weight of the sintered, crushed, and dust-removing ash particles is added, melted, and mixed evenly. The S4 medium-frequency furnace is tilted to discharge slag, and then the remaining molten metal is poured into an alloy tank lined with iron oxide powder and lime powder. After cooling, the slag and iron naturally separate to obtain a new material, silicon-manganese low-titanium ferrometallurgy.

[0005] Further optimization resulted in the dust particle size in S1 being 300-500 mesh.

[0006] Furthermore, the density of the sintered pellets in S1 reaches 4.0-4.3 g / cm³.

[0007] Furthermore, in S1, the rotation speed is set to 60-80 R / min, and the angle between the disk and the horizontal plane is controlled at 40-47°.

[0008] Furthermore, the atomized water in S1 accounts for 2% to 4% of the weight of the dust collected.

[0009] Furthermore, in S2, the high-temperature baking temperature is 1100~1200℃.

[0010] Furthermore, the aluminum added to S3 has a particle size of 5~50mm.

[0011] Furthermore, the S4 intermediate frequency furnace first tilts to release 3 / 4 of the slag into the slag basin, and when the remaining 1 / 4 of the slag is released, the alloy liquid is poured out along with the remaining slag and flushed into the alloy tank.

[0012] Furthermore, in S4, iron oxide powder accounts for 3% of the total weight of the sintered, crushed, and dust-removing ash particles.

[0013] Furthermore, in S4, lime powder accounts for 1% of the total weight of the sintered, crushed, and dust-removing ash particles.

[0014] The advantages and beneficial effects of this invention are: This invention provides a low-cost, binder-free method for producing ferrosilicon manganese low-titanium ferrophosphate by forming sintered pellets and efficiently utilizing dust collector ash. This addresses the problems of low dust collector ash recycling rates, low product added value, and environmental pollution. The method converts essentially waste dust into a high-value-added new material, ferrosilicon manganese low-titanium ferrophosphate, while also allowing some dust collector ash to be directly sintered into the furnace, resulting in high economic efficiency. Specifically, the method includes the following points: 1) This invention uses dust as raw material, and adds aluminum granules, calcium oxide, scrap steel and other materials to melt and react in a medium frequency furnace to obtain a new material, silicon manganese low titanium iron. This is a powerful measure to make full use of titanium resources and obtain high value-added products, breaking through traditional thinking and opening up a new path.

[0015] This invention utilizes sintered titanium slag dust from a medium-frequency furnace. Upon addition of aluminum particles, the aluminum not only reacts with the TiO2 in the sintered particles but also, in the laboratory, undergoes an aluminothermic reaction with MnO2 and SiO2 in the sintered particles, reducing Mn and Si elements. This represents another novel application of the aluminothermic reaction, capable of simultaneously reducing multiple elemental substances and forming a homogeneous solid solution with elements such as Ti and Fe. The reaction formula is as follows: 3TiO2+4Al=2Al2O3+3Ti; 3MnO2+4Al=2Al2O3+Mn; 4Al+3SiO2=2Al2O3+3Si; The new material, ferrosilicon manganese low-titanium ferrophosphate, possesses both silicon and manganese content and the deoxidizing, degassing, and grain-refining properties of ferrosilicon. It will be a high-end additive material to replace ferrosilicon, ferromanganese, ferrosilicon manganese alloy, 30 ferrosilicon, and aluminum additives used in high-end steel production by steel companies, which is of great significance to the production of high-end steel. Most sintered particles are directly made into ferrosilicon manganese low-titanium ferrophosphate, with a cost of approximately 8900 yuan per ton. The market price of ferrosilicon manganese low-titanium ferrophosphate is 15000 yuan / ton, generating a profit of approximately 6000 yuan per ton. The ferrosilicon manganese low-titanium ferrophosphate obtained by this invention has the following composition: titanium 28%-33%, carbon 0.1%-0.2%, silicon dioxide 7%-9%, manganese oxide 8%-9%, copper oxide 0.1%-0.2%, and the remainder being iron. It is a low-titanium ferrophosphate containing silicon and manganese alloy, making it an indispensable deoxidizer and silicon-manganese additive for steel companies.

[0016] 2) The amount of dust collected accounts for about 3% of the amount of titanium ore added during the smelting of titanium slag. The total amount is huge, and its recycling is of great economic significance and is also very important for controlling production costs.

[0017] 3) This invention uses a medium-frequency furnace to smelt dust ash sintered particles. Because the high temperature generated by the medium-frequency furnace allows for the direct addition of small aluminum fragments, it eliminates the cost of expensive metallurgical aluminum powder in the aluminothermic reaction, with a price difference of approximately 5,000 yuan / ton. Furthermore, due to its very low total iron content, it can be used to heat and melt scrap steel in the medium-frequency furnace to become a source of iron, thus eliminating the cost of aluminum for reducing iron and replacing it with inexpensive electricity. This is also one of the important aspects of this invention.

[0018] 4) This invention can effectively reduce the production cost of titanium slag. The price of titanium ore with 50% TiO2 is 2,000 yuan / ton, while the average TiO2 grade of dust removal ash is also 50%, with a price of 200 yuan / ton. After being processed by the process of this invention, it can be directly fed into the furnace to smelt titanium slag, with a sintering cost of about 200 yuan per ton, totaling 400 yuan / ton. In this way, the value of each ton of sintered dust removal ash can be increased by 2,000 - 400 = 1,600 yuan, and the production cost of ton of titanium slag will be reduced by 150 yuan.

[0019] 5) Because an induction furnace is used for the aluminothermic reaction, potassium chlorate, which is used as a heating agent, is eliminated. There are virtually no major emissions throughout the entire process. The dust removal device in the induction furnace can also recover all valuable substances such as alumina and calcium oxide. Apart from a very small amount of nitrogen oxides, there are no major pollutants emitted in the remaining exhaust gas. Attached Figure Description

[0020] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0021] Figure 1 This is a process flow diagram of Embodiment 1 of the present invention; Figure 2 This is a schematic diagram of the working state of the disc granulator; Figure 3 A schematic diagram of pouring molten alloy into an intermediate frequency furnace. Detailed Implementation

[0022] A method for preparing ferrosilicon manganese low-titanium ferrosilicon using dust from a titanium slag smelting furnace includes the following steps: S1 Pellet Preparation: Collect dust from the titanium slag smelting furnace. The test results of the dust used in this embodiment of the invention are: titanium dioxide 48-55%, total iron 9.5%-14%, silicon dioxide 6-9%, and manganese oxide 5-9%.

[0023] In a disc granulator, atomized water is sprayed into the rolling dust, with the atomized water accounting for 2% to 4% of the dust weight. The rotation speed and tilt angle of the disc granulator are controlled, with the rotation speed at 60-80 RPM and the angle between the disc and the horizontal plane controlled at 40-47°. The granules are rolled into pellets with a diameter of 15-40 mm, preferably around 20 mm. These pellets are then fed into a shuttle kiln for drying and sintering at a temperature of 900-1200℃ for 1-2 hours. Due to the ultrafine particle size (300-500 mesh) of the dust, it rapidly agglomerates into dense pellets using the sprayed atomized water droplets as cores. The continuous tumbling and compression of the pellets by the granulator further increases their density. The density of the sintered pellets can reach 4.0-4.3 g / cm³, eliminating the need for further binding agents.

[0024] After S2 sintering, the spherical pellets in the shuttle kiln are layered. The pellets at the top of the shuttle kiln's feed car, in the high-temperature baking section, are sent to a designated area (1100-1200℃ for the high-temperature section, and 980-1090℃ for the remaining sections) for cooling, crushing, and screening to obtain 40-160 mesh sintered crushed dust particles (these 40-160 mesh particles have a particle size close to titanium ore, a relatively complete microstructure, good density, and a relatively low total iron content). The remaining pellets are directly sent to the raw material area, mixed with titanium ore and anthracite particles, and then fed into the submerged arc furnace for further titanium slag smelting. Pellets returned for titanium slag smelting account for 10%~15% of the total sintered pellets. Based on the sintering color, bluish-black pellets are well-sintered and sent to the designated area, while yellowish-red pellets are generally sent to the raw material area and can be easily separated during unloading.

[0025] S3 uses a large medium-frequency furnace to heat the sintered, crushed, and dust-removing ash particles to above 1550℃. After 15 minutes, the material melts, and aluminum and calcium oxide are added. The amount of aluminum added accounts for 40%~60% of the weight of titanium dioxide in the sintered, crushed, and dust-removing ash particles, and the amount of calcium oxide added accounts for 14%~30% of the weight of aluminum. The particle size of aluminum is 5~50mm. Then, scrap steel accounting for 20% of the total weight of the sintered, crushed, and dust-removing ash particles is added, melted, and mixed evenly. After about 5 minutes, slag is discharged. This process essentially reduces the titanium dioxide, causing slag and iron to separate. At the same time, ordinary Q235 steel is used to supplement the iron element, saving the aluminum resources required for iron reduction.

[0026] The S4 medium-frequency furnace first tilts to discharge 3 / 4 of the slag into a slag basin. When the remaining 1 / 4 slag is discharged, the molten alloy is poured out along with it into an alloy tank lined with iron oxide powder and lime powder. After cooling, the slag and iron naturally separate, yielding a new material, silicon-manganese low-titanium ferrometallurgical. At this stage, the remaining slag serves a protective function. Then, a small amount of iron oxide powder and calcium oxide powder are added to the bottom of the alloy tank. The furnace is tilted, and the impact of the molten alloy achieves desulfurization and further strengthening, completing the precipitation of titanium, silicon, and manganese, thus homogenizing the alloy. Finally, after cooling, the alloy is crushed into particles of 5-50 mm for inspection and packaging. In this embodiment, iron oxide powder accounts for 3% of the total weight of the sintered, crushed, and dust-removing ash particles, and lime powder accounts for 1% of the total weight of the sintered, crushed, and dust-removing ash particles.

[0027] Example 1 In S1, atomized water accounts for 2% of the weight of the dust collector ash, the pellet diameter is about 15mm, and the sintering temperature is 900℃; in S3, the medium-frequency furnace heats the dust collector ash to 1700℃, the amount of aluminum added accounts for 47% of the weight of titanium dioxide in the sintered and crushed dust collector ash particles, and the amount of calcium oxide added accounts for 25% of the weight of aluminum; then, scrap steel accounting for 20% of the total weight of the sintered and crushed dust collector ash particles is added.

[0028] The obtained silicon-manganese low-titanium iron composition: Carbon 0.12%, titanium 32%, silicon dioxide 7.8%, manganese oxide 8.25%, phosphorus 0.02%, sulfur 0.033%, copper oxide 0.17%, balance iron. Yield 77%.

[0029] Example 2 In S1, atomized water accounts for 3% of the weight of the dust collector ash, the pellet diameter is about 25mm, and the sintering temperature is 1000℃; in S3, the medium-frequency furnace heats the dust collector ash to 1700℃, the amount of aluminum added accounts for 52% of the weight of titanium dioxide in the sintered and crushed dust collector ash particles, the amount of calcium oxide added accounts for 18% of the weight of aluminum; and then 20% of the total weight of the sintered and crushed dust collector ash particles of scrap steel are added.

[0030] The obtained silicon-manganese low-titanium iron composition: Carbon 0.15%, titanium 31%, silicon dioxide 8.43%, manganese oxide 9.0%, phosphorus 0.03%, sulfur 0.037%, copper oxide 0.19%, balance iron, yield 81%.

[0031] Example 3 In S1, atomized water accounts for 4% of the weight of the dust collector ash, the pellet diameter is about 40mm, and the sintering temperature is 1100℃; in S3, the medium-frequency furnace heats the dust collector ash to 1700℃, the amount of aluminum added accounts for 59% of the weight of titanium dioxide in the sintered and crushed dust collector ash particles, and the amount of calcium oxide added accounts for 14% of the weight of aluminum; then, scrap steel accounting for 20% of the total weight of the sintered and crushed dust collector ash particles is added.

[0032] The obtained silicon-manganese low-titanium iron composition: Carbon 0.12%, titanium 29%, silicon dioxide 8.06%, manganese oxide 8.34%, phosphorus 0.02%, sulfur 0.023%, copper oxide 0.21%, balance iron, yield 79%.

[0033] Comparative Example 1 Compared to Example 1, this comparative example adds 1% water droplets, while other operations are the same as in Example 1.

[0034] Result: The spheres did not form properly, were prone to crumbling, and lacked sufficient density.

[0035] Comparative Example 2 Compared to Example 1, this comparative example adds 5% water droplets, while other operations are the same as in Example 1.

[0036] As a result, the balls rolled to a diameter of more than 60mm, making it difficult for the shuttle kiln to burn them thoroughly and subsequent crushing and processing to be difficult, resulting in a core formation phenomenon.

[0037] Comparative Example 3 Compared to Example 1, the diameter of the pellets in this comparative example is 5 mm.

[0038] Result: The overall air permeability of the balls piled on the shuttle kiln material car was extremely poor. Because the ball diameter was small and the gap between the balls was small, the lower part of the balls on the material car was not burned properly, resulting in a large number of unburnt balls.

[0039] Comparative Example 4 Compared to Example 1, the diameter of the pellets in this comparative example is 50 mm.

[0040] Result: The inside of the balls was not burned properly, making subsequent crushing difficult, and there were too many raw balls, which seriously affected product quality.

[0041] Comparative Example 5 Compared to Example 1, the sintering temperature of this comparative example is 800°C, and all other operations are the same as in Example 1.

[0042] Result: The balls on the material cart were generally raw balls, which were not sintered properly or were basically not sintered, and could not be used in subsequent processes.

[0043] Comparative Example 6 Compared to Example 1, the sintering temperature of this comparative example was 1300°C, and all other operations were the same as in Example 1.

[0044] Result: Sintering was good, but large areas of ball adhesion occurred, making it impossible to enter the crusher. Manual coarse crushing was required before the balls could enter the crusher.

[0045] Comparative Example 7 After testing the crushed sintered dust, waste aluminum was added at 30% of the titanium dioxide content. Other operations were the same as in Example 1.

[0046] Results: The yield of ferrosilicon manganese low-titanium iron decreased to 57% because of the lack of aluminum participation, and titanium dioxide exceeded 25% in the slag phase.

[0047] Comparative Example 8 After testing the crushed sintered dust, waste aluminum was added at 70% of the titanium dioxide content. Other operations were the same as in Example 1.

[0048] Result: The aluminum content in the silicon-manganese low-titanium iron was above 9.0%, which did not meet the standard and resulted in a waste of aluminum resources.

[0049] Comparative Example 9 Add calcium oxide powder at 10% of the amount of waste aluminum added, and perform the other operations as in Example 1.

[0050] Results: The separation of slag and gold was poor, and the recovery rate was very low, around 45%.

[0051] Comparative Example 10 Add calcium oxide powder at 40% of the amount of waste aluminum added, and perform other operations as in Example 1.

[0052] Result: The low temperature resulted in poor reactivity because all the materials involved in the reaction absorbed a large amount of heat due to the increase in calcium oxide powder, leading to decreased reactivity.

[0053] Finally, it should be noted that the above description is only used to illustrate the technical solutions of the present invention and is not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the present invention.

Claims

1. A method for preparing ferrosilicon manganese low-titanium ferrosilicon using dust from a titanium slag smelting furnace, characterized in that, Includes the following steps: S1 Pellet Preparation: Collect dust from the titanium slag smelting furnace, spray atomized water into the rolling dust in a disc granulator, the atomized water accounts for 2%~4% of the weight of the dust, control the rotation speed and tilt angle of the disc granulator, roll into pellets with a diameter of 15~40mm, and send the pellets into a shuttle kiln for drying and sintering, the sintering temperature is 900-1200℃, and the duration is 1-2 hours; After the S2 sintering is completed, the spheres in the shuttle kiln are layered. The spheres at the top of the shuttle kiln material car in the high-temperature baking part are sent to the designated area for cooling, crushing and screening to obtain 40-160 mesh sintered crushed dust particles. The remaining spheres are sent directly to the raw material area and fed into the electric arc furnace to continue smelting titanium slag. S3 uses a medium-frequency furnace to heat the sintered, crushed, and dust-removing ash particles to above 1550°C. Once the material melts, aluminum and calcium oxide are added. The amount of aluminum added accounts for 40% to 60% of the weight of titanium dioxide in the sintered, crushed, and dust-removing ash particles, and the amount of calcium oxide added accounts for 14% to 30% of the weight of aluminum. Then, steel accounting for 20% of the total weight of the sintered, crushed, and dust-removing ash particles is added, melted, and mixed evenly. The S4 medium-frequency furnace is tilted to discharge slag, and then the remaining molten metal is poured into an alloy tank lined with iron oxide powder and lime powder. After cooling, the slag and iron naturally separate to obtain silicon-manganese low-titanium ferrometallurgy.

2. The method for preparing ferrosilicon manganese low-titanium ferrosilicon using dust from a titanium slag smelting furnace according to claim 1, characterized in that: The particle size of the dust collected in S1 is 300-500 mesh.

3. The method for preparing ferrosilicon manganese low-titanium ferrosilicon using dust from a titanium slag smelting furnace according to claim 1, characterized in that: The density of the sintered pellets in S1 reaches 4.0-4.3 g / cm³.

4. The method for preparing ferrosilicon manganese low-titanium ferrosilicon using dust from a titanium slag smelting furnace according to claim 1, characterized in that: In S1, the rotation speed is set to 60-80 R / min, and the angle between the disk and the horizontal plane is controlled at 40-47°.

5. The method for preparing ferrosilicon manganese low-titanium ferrosilicon using dust from a titanium slag smelting furnace according to claim 1, characterized in that: In S2, the high-temperature baking temperature is 1100~1200℃.

6. The method for preparing ferrosilicon manganese low-titanium ferrosilicon using dust from a titanium slag smelting furnace according to claim 1, characterized in that: The aluminum added to S3 has a particle size of 5~50mm.

7. The method for preparing ferrosilicon manganese low-titanium ferrosilicon using dust from a titanium slag smelting furnace according to claim 1, characterized in that: The S4 medium-frequency furnace first tilts to release 3 / 4 of the slag into the slag basin, and when the remaining 1 / 4 of the slag is released, the alloy liquid is poured out along with the remaining slag and flushed into the alloy tank.

8. The method for preparing ferrosilicon manganese low-titanium ferrosilicon using dust from a titanium slag smelting furnace according to claim 1, characterized in that: In S4, iron oxide powder accounts for 3% of the total weight of the sintered, crushed, and dust-removing ash particles.

9. The method for preparing ferrosilicon manganese low-titanium ferrosilicon using dust from a titanium slag smelting furnace according to claim 1, characterized in that: In S4, lime powder accounts for 1% of the total weight of the sintered, crushed, and dust-removing ash particles.

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