A method for preparing a silicon-calcium-aluminum alloy or a silicon-calcium-aluminum-iron alloy from industrial silicon slag

Abstract

The application discloses a method for preparing a silicon-calcium-aluminum alloy or a silicon-calcium-aluminum-iron alloy from industrial silicon slag, and belongs to the field of metallurgy.The method mainly comprises the following steps: (1) crushing and grinding the industrial silicon slag; (2) mixing the powdered industrial silicon slag with a selected carbon source / iron-containing concentrate / iron filings in a certain proportion; (3) high-temperature smelting the mixed material; and (4) after the smelting is completed and the material is cooled, crushing and packaging the material to obtain the silicon-calcium-aluminum alloy or the silicon-calcium-aluminum-iron alloy.The method provides a new way for recycling the industrial silicon slag, can make the industrial silicon slag be more effectively utilized, and reduces the pollution problem of the solid waste of the industrial silicon slag.

Description

Technical Field

[0001] This invention belongs to the field of metallurgy, and specifically relates to a method for preparing silicon-calcium-aluminum alloy or silicon-calcium-aluminum-iron alloy from industrial silicon slag. Background Technology

[0002] Industrial silicon, also known as metallurgical silicon, metallic silicon, or crude silicon, refers to a product containing over 97% Si, obtained by smelting silicon oxide-containing minerals and carbonaceous reducing agents in an electric furnace. Industrial silicon is an important component of the non-ferrous metals industry, and is widely used in metallurgy, chemicals, new energy, and communications, primarily for alloy formulation, manufacturing high-purity semiconductors, and producing organosilicon products such as silicone rubber, silicone resin, and silicone oil. Furthermore, its low price and simple manufacturing process make it the ideal raw material for solar cells.

[0003] Silicon slag is a type of slag produced during the industrial silicon production and refining processes. Due to its high viscosity, elemental silicon inevitably gets trapped within the slag during the separation of molten silicon and the slag. The elemental silicon content in silicon slag is generally around 15%-30% by mass. This slag is usually either directly dumped or used for road paving, causing not only environmental pollution but also a serious waste of resources.

[0004] Current research on industrial silicon slag recycling, both domestically and internationally, primarily focuses on recovering elemental silicon from the slag. Some studies also examine the physicochemical properties of industrial silicon slag and its smelting reaction mechanisms. Others utilize industrial silicon slag to produce glass ceramics. Analysis has revealed that the slag phase in industrial silicon slag mainly consists of silicon, calcium, and aluminum. Utilizing industrial silicon slag to prepare silicon-calcium-aluminum alloys / silicon-calcium-aluminum-iron alloys provides a new approach to its recycling. This not only recovers residual elemental silicon but also reduces the silicon, calcium, and aluminum elements in the slag phase, achieving more effective recycling. This not only enables the reuse of industrial silicon slag and brings certain economic benefits but also reduces solid waste pollution, offering multiple advantages. Summary of the Invention

[0005] To address the shortcomings of the prior art, this invention provides a method for preparing silicon-calcium-aluminum alloys or silicon-calcium-aluminum-iron alloys from industrial silicon slag. This method offers a new approach to the recycling and utilization of industrial silicon slag, enabling more effective use of the slag and effectively solving the problems in the prior art.

[0006] The solution adopted in this invention is as follows:

[0007] A method for preparing silicon-calcium-aluminum alloy or silicon-calcium-aluminum-iron alloy from industrial silicon slag includes the following steps:

[0008] (1) Industrial silicon slag is crushed and ground;

[0009] (2) Powdered industrial silicon slag is mixed with a carbon source in a certain proportion to prepare silicon-calcium-aluminum alloy;

[0010] or

[0011] Powdered industrial silicon slag is mixed with carbon source and iron-containing concentrate / iron scrap in a certain proportion to prepare silicon-calcium-aluminum-iron alloy;

[0012] (3) The mixed materials are smelted at high temperature;

[0013] (4) After being taken out of the furnace and left to cool, the silicon-calcium-aluminum alloy / silicon-calcium-aluminum-iron alloy is obtained by crushing and packaging.

[0014] The above-mentioned method for preparing silicon-calcium-aluminum alloy or silicon-calcium-aluminum-iron alloy from industrial silicon slag, wherein:

[0015] Preferably, in step (1), the industrial silicon slag is a solid silicon slag mainly composed of SiO2-CaO-Al2O3 ternary oxides, produced during the industrial silicon production and refining process. The content of SiO2-CaO-Al2O3 ternary oxides in the industrial silicon slag is greater than 70%.

[0016] Preferably, in step (2), the carbon source is one or a mixture of several of petroleum coke, semi-coke, coal, charcoal, and graphite powder.

[0017] Preferably, in step (2), carbon and industrial silicon slag powder are mixed according to the amount of carbon required for the reduction of silicon calcium aluminum oxide in industrial silicon slag, that is, the molar ratio of O to added C in silicon calcium aluminum oxide in industrial silicon slag is 1:(0.7~1.3), and the carbon loss rate is 2%~15%.

[0018] Preferably, in step (2), the amount of iron added is 5% to 30% of the mass of industrial silicon slag, calculated according to the iron content in the iron concentrate / iron scrap.

[0019] In the process of preparing silicon-calcium-aluminum-iron alloy, the iron-containing concentrate / iron scrap in step (2) can be transferred to step (3), and the mixed industrial silicon slag + carbon source and the weighed iron-containing concentrate / iron scrap can be added together to the heating equipment for high-temperature smelting.

[0020] Preferably, in step (3), the smelting temperature is 1500-3000℃.

[0021] Preferably, in step (3), the reduction method used is carbothermal reduction.

[0022] Preferably, the heating equipment used in step (3) includes an electric arc furnace, an induction furnace, and a resistance furnace.

[0023] Compared with the prior art, the advantages of the present invention are as follows:

[0024] Industrial silicon slag is generally used as a paving material or for further recycling of the elemental silicon within it. The method of this invention not only recovers and reuses the residual elemental silicon in industrial silicon slag, but also reduces the silicon, calcium, and aluminum elements in the slag phase, significantly reducing solid waste generation and achieving more effective recycling. The resulting silicon-calcium-aluminum alloy / silicon-calcium-aluminum-iron alloy can be used as a deoxidizer in steelmaking, an additive in alloy production, and also in casting, deformation processing, construction, and automobile manufacturing. Attached Figure Description

[0025] Figure 1 This is a process flow diagram of the present invention for preparing silicon-calcium-aluminum alloy / silicon-calcium-aluminum-iron alloy using industrial silicon slag. Detailed Implementation

[0026] like Figure 1 As shown, a method for preparing silicon-calcium-aluminum alloy or silicon-calcium-aluminum-iron alloy from industrial silicon slag includes the following steps:

[0027] (1) The industrial silicon slag is crushed and ground into powder, and the content of SiO2-CaO-Al2O3 ternary oxides in the industrial silicon slag is greater than 70%.

[0028] (2) Mix the powdered industrial silicon slag with a carbon source, or mix the powdered industrial silicon slag with a carbon source and iron-containing concentrate / iron scrap in a certain proportion; specifically, the carbon source is weighed with a carbon loss rate of 2% to 15% based on the molar ratio of O to C in the silicon-calcium-aluminum oxide of the industrial silicon slag being 1:(0.7 to 1.3), and the carbon source is one or a mixture of petroleum coke, semi-coke, coal, charcoal, and graphite powder; iron-containing concentrate / iron scrap is weighed according to the iron addition amount being 5% to 30% of the mass of the industrial silicon slag raw material.

[0029] (3) The mixed materials are smelted at high temperature; the smelting temperature is 1500-3000℃, the reduction method is carbothermal reduction, and the heating equipment is an electric arc furnace, induction furnace or resistance furnace.

[0030] (4) After being taken out of the furnace and left to cool, the silicon-calcium-aluminum alloy or silicon-calcium-aluminum-iron alloy is obtained by crushing and packaging.

[0031] Example 1

[0032] A method for preparing silicon-calcium-aluminum alloy from industrial silicon slag, the specific operation steps of which are as follows:

[0033] (1) Industrial silicon slag is crushed and ground;

[0034] (2) Mix the powdered industrial silicon slag with the carbon source in the following proportion: Specifically, the molar ratio of O to C in the silicon-calcium-aluminum oxide of the industrial silicon slag is 1:0.7, and the carbon source is weighed with a carbon loss rate of 5%. The carbon source is petroleum coke.

[0035] (3) The mixed materials are smelted at high temperature; the heating temperature is 2000℃~3000℃, the reduction method is carbothermal reduction, and the heating equipment is an electric arc furnace;

[0036] (4) After being taken out of the furnace and left to cool, the silicon-calcium-aluminum alloy is obtained by crushing and packaging.

[0037] Example 2

[0038] A method for preparing silicon-calcium-aluminum alloy from industrial silicon slag, the specific operation steps of which are as follows:

[0039] (1) Industrial silicon slag is crushed and ground;

[0040] (2) Mix the powdered industrial silicon slag with the carbon source in the following proportion; specifically, the molar ratio of O to C in the silicon-calcium-aluminum oxide of the industrial silicon slag is 1:0.9, and the carbon source is weighed with a carbon loss rate of 5%. The carbon source is petroleum coke.

[0041] (3) The mixed materials are smelted at high temperature; the heating temperature is 2000℃~3000℃, the reduction method is carbothermal reduction, and the heating equipment is an electric arc furnace;

[0042] (4) After being taken out of the furnace and left to cool, the silicon-calcium-aluminum alloy is obtained by crushing and packaging.

[0043] Example 3

[0044] A method for preparing silicon-calcium-aluminum-iron alloy from industrial silicon slag, the specific operation steps of which are as follows:

[0045] (1) Industrial silicon slag is crushed and ground;

[0046] (2) Mix the powdered industrial silicon slag with the carbon source and iron filings in the following proportions: Specifically, the molar ratio of O to C in the silicon-calcium-aluminum oxide of the industrial silicon slag is 1:1.1, and the carbon source is weighed with a carbon loss rate of 5%. The carbon source is semi-coke. Iron filings are weighed according to the amount of iron added being 5% of the mass of the industrial silicon slag raw material.

[0047] (3) The mixed materials are smelted at high temperature; the heating temperature is 2000℃~3000℃, the reduction method is carbothermal reduction, and the heating equipment is an electric arc furnace;

[0048] (4) After being taken out of the furnace and left to cool, the silicon-calcium-aluminum-iron alloy is obtained by crushing and packaging.

[0049] Example 4

[0050] A method for preparing silicon-calcium-aluminum-iron alloy from industrial silicon slag, the specific operation steps of which are as follows:

[0051] (1) Industrial silicon slag is crushed and ground;

[0052] (2) Mix the powdered industrial silicon slag with the carbon source in the following proportion: Specifically, the molar ratio of O to C in the silicon-calcium-aluminum oxide of the industrial silicon slag is 1:0.9, and the carbon source is weighed with a carbon loss rate of 7%. The carbon source is petroleum coke.

[0053] (3) The mixed materials and weighed iron filings are smelted at high temperature; the iron filings are weighed according to the iron addition amount being 10% of the mass of the industrial silicon slag raw material; the heating temperature is 2000℃~3000℃, the reduction method is carbothermal reduction, and the heating equipment is an electric arc furnace.

[0054] (4) After being taken out of the furnace and left to cool, the silicon-calcium-aluminum-iron alloy is obtained by crushing and packaging.

[0055] Example 5

[0056] A method for preparing silicon-calcium-aluminum-iron alloy from industrial silicon slag, the specific operation steps of which are as follows:

[0057] (1) Industrial silicon slag is crushed and ground;

[0058] (2) Mix the powdered industrial silicon slag with the carbon source and iron-containing concentrate in the following proportions: Specifically, the molar ratio of O to C in the silicon-calcium-aluminum oxides of the industrial silicon slag is 1:0.9, and the carbon source is weighed with a carbon loss rate of 7%. The carbon source is petroleum coke. The iron-containing concentrate is weighed according to the iron addition amount being 15% of the mass of the industrial silicon slag raw material.

[0059] (3) The mixed materials are smelted at high temperature; the heating temperature is 2000℃~3000℃, the reduction method is carbothermal reduction, and the heating equipment is an electric arc furnace;

[0060] (4) After being taken out of the furnace and left to cool, the silicon-calcium-aluminum-iron alloy is obtained by crushing and packaging.

[0061] Example 6

[0062] A method for preparing silicon-calcium-aluminum-iron alloy from industrial silicon slag, the specific operation steps of which are as follows:

[0063] (1) Industrial silicon slag is crushed and ground;

[0064] (2) Mix the powdered industrial silicon slag with the carbon source and iron filings in the following proportions: Specifically, the molar ratio of O to C in the silicon-calcium-aluminum oxide of the industrial silicon slag is 1:0.9, and the carbon source is weighed with a carbon loss rate of 10%. The carbon source is petroleum coke. The amount of iron filings is weighed according to the amount of iron added being 15% of the mass of the industrial silicon slag raw material.

[0065] (3) The mixed materials are smelted at high temperature; the heating temperature is 2200℃, the reduction method is carbothermal reduction, and the heating equipment is a resistance furnace.

[0066] (4) After being taken out of the furnace and left to cool, the silicon-calcium-aluminum-iron alloy is obtained by crushing and packaging.

[0067] The silicon-calcium-aluminum alloy prepared in Example 2 was subjected to compositional analysis, and the results are shown in Table 1 below:

[0068] Table 1 Main components of the prepared silicon-calcium-aluminum alloy

[0069]

[0070]

[0071] The silicon-calcium-aluminum-iron alloy prepared in Example 4 was subjected to compositional analysis, and the results are shown in Table 2 below:

[0072] Table 2 Main components of the prepared silicon-calcium-aluminum-iron alloy

[0073]

[0074] As can be seen from the above, the silicon-calcium-aluminum-iron alloy prepared in Example 4 is close to the PGFeSi65 standard in GB / T 2272-2020, and can be used after further impurity removal.

[0075] The above description is merely a specific embodiment of the present invention, and the scope of protection of the present invention is not limited thereto. The scope of protection of the present invention should be determined by the scope of protection of the claims.

Claims

1. A method for preparing silicon-calcium-aluminum alloy or silicon-calcium-aluminum-iron alloy from industrial silicon slag, characterized in that... Follow these steps: (1) The industrial silicon slag is crushed and ground; the content of SiO2-CaO-Al2O3 ternary oxides in the industrial silicon slag is greater than 70%; (2) Powdered industrial silicon slag is mixed with a carbon source in a certain proportion to prepare silicon-calcium-aluminum alloy; or Powdered industrial silicon slag is mixed with carbon source and iron-containing concentrate / iron scrap in a certain proportion to prepare silicon-calcium-aluminum-iron alloy; the amount of iron added is 5% to 30% of the mass of industrial silicon slag, calculated according to the iron content in the iron-containing concentrate / iron scrap. The carbon source is added according to the molar ratio of O to C in the silicon-calcium-aluminum oxide in industrial silicon slag being 1:(0.7~1.3), and the carbon loss rate being 2%~15%. (3) The mixed materials are smelted at high temperature; (4) After being taken out of the furnace and left to cool, the silicon-calcium-aluminum alloy or silicon-calcium-aluminum-iron alloy is obtained by crushing and packaging.

2. The method for preparing silicon-calcium-aluminum alloy or silicon-calcium-aluminum-iron alloy from industrial silicon slag according to claim 1, characterized in that... In step (2), the carbon source is one or a mixture of several of petroleum coke, semi-coke, coal, charcoal, and graphite powder.

3. The method for preparing silicon-calcium-aluminum alloy or silicon-calcium-aluminum-iron alloy from industrial silicon slag according to claim 1, characterized in that... In step (3), the smelting temperature is 1500~3000℃.

4. The method for preparing silicon-calcium-aluminum alloy or silicon-calcium-aluminum-iron alloy from industrial silicon slag according to claim 1, characterized in that... In step (3), the reduction method used is carbothermal reduction.

5. The method for preparing silicon-calcium-aluminum alloy or silicon-calcium-aluminum-iron alloy from industrial silicon slag according to claim 1, characterized in that... In step (3), the heating equipment used is an electric arc furnace, an induction furnace, or a resistance furnace.

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