Auxiliary material for industrial silicon production as well as preparation method and soak solution thereof

Abstract

The invention relates to an auxiliary material for industrial silicon production, a preparation method of the auxiliary material and a soak solution. The soaking solution for the auxiliary materials for industrial silicon production comprises the following components in parts by weight: silica powder, silica sol, a sodium silicate solution, methyl cellulose, starch, a silane coupling agent and the balance of water, and every 100 parts of the soaking solution comprises the following components in parts by weight: silica powder, silica sol, a sodium silicate solution, methyl cellulose, starch, a silane coupling agent and the balance of water. The invention relates to a preparation method of an auxiliary material for industrial silicon production, which comprises the following steps: step 1, in parts by weight, per 100 parts of soaking solution comprises silica powder, silica sol, a sodium silicate solution, methyl cellulose, starch, a silane coupling agent and the balance of water; step 2, soaking the auxiliary materials in a soaking solution at normal temperature; and step 3, sieving and draining the auxiliary material soaked in the step 2 to obtain the auxiliary material for industrial silicon production. The invention also comprises granular coal or wood chips treated by a soaking solution. The method has the advantages that the use mode is simple, auxiliary materials are fully soaked in the soaking solution for a certain time and then filtered and drained, and the soaking solution is easy to popularize and use due to the fact that the raw materials of the soaking solution are simple and easy to obtain.

Description

Technical Field

[0001] This invention relates to the field of industrial silicon production technology, and in particular to auxiliary materials for industrial silicon production, their preparation methods, and soaking solutions. Background Technology

[0002] In the process of industrial silicon production, auxiliary materials are a very important reactant, which mainly include wood chips and granular coal.

[0003] Wood chips are an important component of raw materials for industrial silicon production. In the process of industrial silicon production, wood chips are mainly added to prevent the raw materials from sintering in the electric arc furnace, maintain good air permeability so that the silicon ore can be uniformly sintered and fully combined with the reducing agent and reducing gas. In addition, some wood chips that are not burned and carbonized can also participate in the silicon reduction process.

[0004] Currently, industrial silicon uses wood chips made by directly mixing logs with reducing agents such as silica and granular coal before feeding them into the furnace. Such wood chips burn quickly in the submerged arc furnace with a low carbonization rate. At the same time, the permeability of the material layer in the furnace is uneven and the heat distribution is uneven. Some silica cannot be fully burned and shrinks, forming a molten state and sticking together. This causes the raw material to directly enter the furnace bottom, making it difficult to fully reduce and affecting the furnace condition and output.

[0005] The industrial silicon production process generates a large amount of flue gas that is discharged through the flue. The dust removal equipment captures and collects the micro silicon powder, which has the characteristics of high silica content, small particle size, high heat resistance, good flow and easy penetration after wetting. However, it has not been effectively recycled.

[0006] Particle coal is currently the main reducing agent in industrial silicon production. Industrial silicon is obtained by reducing silica with a silicon dioxide content of over 98.5% with carbon in a submerged arc furnace under high temperature and pressure. Particle coal is used as a carbon reducing agent and is mixed with raw materials such as silica and wood chips and put into the furnace for smelting. The carbon monoxide and carbon dioxide gases generated by the coal permeate into the pores of silica, while the silica and silicon monoxide gases permeate into the pores of the particle coal. The two react with each other to form liquid silicon.

[0007] Currently, the granular coal used in industrial silicon production is mixed with reducing agents such as silica and wood chips after being finely washed and dehydrated, and then directly fed into the furnace. Due to the high temperature inside the submerged arc furnace, the temperature of the upper material layer is generally 700-1200℃. During this roasting period, the granular coal suffers severe burn-off and oxidation, and its pyrolysis is also relatively rapid. The carbon-containing gases produced fail to react with the silica and overflow from the furnace surface, causing waste and putting pressure on environmental protection. At the same time, due to the severe burn-off of the granular coal, some silica forms a molten state and sticks together, causing the raw material with red flames on the furnace surface to directly enter the furnace bottom, which is not easy to fully reduce, affecting the furnace condition and output.

[0008] The industrial silicon production process generates a large amount of flue gas that is discharged through the flue. The dust removal equipment captures and collects the micro silicon powder, which has the characteristics of high silica content, small particle size, high heat resistance, good flow and easy penetration after wetting. However, it has not been effectively recycled. Summary of the Invention

[0009] The purpose of this invention is to provide an auxiliary material for industrial silicon production, its preparation method, and an immersion solution. The auxiliary material for industrial silicon production obtained through the immersion solution can improve the reaction efficiency and increase the production yield of industrial silicon.

[0010] The objective of this invention is achieved as follows: an immersion solution for industrial silicon production auxiliary materials, comprising, by weight parts, 10-35 parts of silicon micropowder, 5-20 parts of silica sol, 5-20 parts of sodium silicate solution, 0-1 part of methylcellulose, 0-1 part of starch, 0-1 part of silane coupling agent, and the balance being water.

[0011] A method for preparing an auxiliary material for industrial silicon production, comprising the following steps:

[0012] Step 1, by weight, each 100 parts of soaking solution includes 10-35 parts of silica powder, 5-20 parts of silica sol, 5-20 parts of sodium silicate solution, 0-1 part of methylcellulose, 0-1 part of starch, 0-1 part of silane coupling agent; the balance is water.

[0013] Step 2: Soak the excipients from the previous step in the soaking solution at room temperature for 3 minutes to 3 hours;

[0014] Step 3: Sieve and drain the excipients soaked in Step 2 to obtain the excipients for industrial silicon production.

[0015] The auxiliary materials for industrial silicon production obtained by the manufacturing method include granular coal or wood chips that have been treated with a soaking solution.

[0016] The advantages of this invention are:

[0017] 1. It is easy to use. Simply soak the auxiliary material in the soaking solution for a certain period of time, then filter and drain it before use. It is convenient to use, and because the raw materials of the soaking solution are simple and readily available, it is easy to promote its use.

[0018] 2. The granular coal prepared by this invention is not easily oxidized and burned, delays the pyrolysis of the granular coal, allows the carbon gas in the pyrolysis process to enter the pores of the calcined silica for reduction, and can be combined with microsilica powder for recycling and reuse. It has the effects of good material layer permeability, not easy to melt and stick and cause red fire, reducing the amount of reducing agent, stabilizing furnace conditions, and increasing output.

[0019] 3. The wood chips produced by this invention are not easily burned, are efficiently carbonized and participate in reduction, and can be recycled and reused in combination with microsilica powder. They have the effects of good material layer permeability, are not easily melted and stuck together to cause red fire, reduce the amount of reducing agent, stabilize furnace conditions, and increase output. Attached Figure Description

[0020] Figure 1 This is a comparison chart of traditional granular coal and granular coal soaked for 5 minutes using Formula 1. Figure 1 The material at the top is traditional granular coal, while the material at the bottom is granular coal that has been soaked for 5 minutes.

[0021] Figure 2 for Figure 1 The state changes of conventional granular coal and granular coal soaked in formula 1 for 5 minutes after being heated by flame for 5 minutes; Figure 2 The material at the top is traditional granular coal, while the material at the bottom is granular coal that has been soaked for 5 minutes.

[0022] Figure 3 for Figure 1 Traditional granular coal and granular coal soaked for 5 minutes according to Formula 1 are in Figure 2 The diagram shows the changes in state after the flame is continued to heat and burn for 10 minutes. Figure 3 The material at the top is traditional granular coal, while the material at the bottom is granular coal that has been soaked for 5 minutes.

[0023] Figure 4 A comparison chart showing traditional granular coal and granular coal soaked for 20 minutes using Formula 2; among them, Figure 4 The material at the top is traditional granular coal, while the material at the bottom is granular coal that has been soaked for 20 minutes.

[0024] Figure 5 for Figure 4 The state changes of conventional granular coal and granular coal soaked in Formula 2 for 20 minutes after being heated by flame for 10 minutes.

[0025] Figure 6 This is a comparison image of traditional wood chips and wood chips soaked in Formula 1 for 3 minutes. Figure 6 The upper part is the traditional wood chip, and the lower part is the wood chip that has been soaked for 3 minutes.

[0026] Figure 7 for Figure 6 The state changes of traditional wood chips and wood chips soaked in Formula 1 for 3 minutes after being heated in a flame for 5 minutes; Figure 7 The upper part is the traditional wood chip, and the lower part is the wood chip that has been soaked for 3 minutes.

[0027] Figure 8 for Figure 6The state changes of traditional wood chips and wood chips soaked in Formula 1 for 3 minutes after being heated in a flame for 10 minutes; Figure 8 The upper part is the traditional wood chip, and the lower part is the wood chip that has been soaked for 3 minutes.

[0028] Figure 9 A comparison image showing traditional wood chips and wood chips soaked in Formula 2 for 20 minutes; among them, Figure 9 The upper part is made of traditional wood chips, while the lower part is made of wood chips that have been soaked for 20 minutes.

[0029] Figure 10 for Figure 9 The diagram shows the changes in state of traditional wood chips and wood chips soaked in Formula 2 for 20 minutes after being heated in a flame for 10 minutes; among them, Figure 10 The upper part is made of traditional wood chips, while the lower part is made of wood chips that have been soaked for 20 minutes. Detailed Implementation

[0030] The present invention will now be described in detail with reference to the accompanying drawings:

[0031] Example 1

[0032] Immersion solution for auxiliary materials used in industrial silicon production. By weight, each hundred parts of the solution comprises silica powder, silica sol, sodium silicate solution, methylcellulose, starch, silane coupling agent, and water. Currently, based on the different proportions of the components, the following three formulations are derived.

[0033] Formula 1 Formula 2 Formula 3 Silica powder 13.5 16 25 silica sol 6 9 5 Sodium silicate solution 6 9 5 Methylcellulose 0.3 0.5 0 starch 0.3 0 0.3 Silane coupling agents 0.2 0.3 0.5 water margin margin margin

[0034] In Formula 1, the solubility of silica sol is 50%, and the solubility of sodium silicate solution is 40%.

[0035] The solubility of silica sol in Formula 2 is 30%, and the solubility of sodium silicate solution is 35%.

[0036] The solubility of silica sol in Formula 3 is 20%, and the solubility of sodium silicate solution is 50%.

[0037] Example 1

[0038] The above solution is used as an immersion solution to soak the granular coal, with 50 parts granular coal added to every 100 parts immersion solution. During the soaking process, it is generally necessary to ensure that the immersion solution completely submerges the auxiliary material (in actual use, a drum spray method can also be used). Finally, the soaked auxiliary material is sieved and drained to obtain the auxiliary material for industrial silicon production.

[0039] The following section explains the effectiveness of using granular coal based on specific parameters.

[0040] Flame heating and combustion Traditional pellet coal Formula 1 granule Formula 2 granules Formula 3 granules Soaking time 5 minutes Significant oxidative splitting ( Figure 2 ) No obvious splitting oxidation was observed. Figure 2 ) No obvious splitting or oxidation was observed. No obvious splitting oxidation was observed. 5 minutes 10 minutes Obvious burn-off and oxidation Slight burn oxidation Slight burn oxidation Slight burn oxidation 5 minutes 10 minutes Severe burn damage ( Figure 3 () Figure 4 ) Severe burn damage ( Figure 3 ) No severe burn damage was observed. Figure 4 ) No severe burn damage observed 20 minutes

[0041] in Figure 1 , 2 Images 3, 4, and 5 are pictures of some of the granular coal in the table above after processing (soaking, burning).

[0042] Example 2

[0043] Wood chips are soaked in the above solution, with 50 parts wood chips added to every 100 parts of the soaking solution. During soaking, it is generally necessary to ensure that the soaking solution completely submerges the auxiliary material (in actual use, a drum spray method can also be used). Finally, the soaked auxiliary material is sieved and drained to obtain the auxiliary material for industrial silicon production.

[0044] The following section explains the effects of using wood chips with specific parameters.

[0045] Flame heating and combustion Traditional wood chips Formula 1: Wood Chips Formula 2: Wood Chips Formula 3: Wood Chips Soaking time 5 minutes The surface begins to oxidize noticeably. Figure 7 ) No obvious oxidation was observed. Figure 7 ) No obvious oxidation was observed. No obvious oxidation was observed. 3 minutes 10 minutes Severe burn-off and oxidation Slight burn oxidation Slight burn oxidation Slight burn oxidation 3 minutes 10 minutes Severe burn-off and oxidation ( Figure 9 () Figure 10 ) No severe burn damage was observed. Figure 9 ) No severe burn damage was observed. Figure 10 ) No severe burn damage observed 20 minutes

[0046] in Figure 6-10 The images shown are of some of the wood chips in the table above after treatment (soaking, burning).

[0047] The above parameters and pictures demonstrate that the auxiliary materials soaked in the soaking solution disclosed in this invention have good effects. It should be noted that the refractoriness of granular coal and wood chips disclosed in this invention is also applicable to ferrosilicon and calcium carbide reducing agent semi-coke.

[0048] Finally, it should be noted that the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. An immersion solution for auxiliary materials used in industrial silicon production, characterized in that: By weight, each 100 parts of the solution comprises 10-35 parts of silica powder, 5-20 parts of silica sol, 5-20 parts of sodium silicate solution, 0-1 part of methylcellulose, 0-1 part of starch, 0-1 part of silane coupling agent, and the balance being water.

2. The immersion solution for auxiliary materials in industrial silicon production according to claim 1, characterized in that: The solubility of the silica sol is 15%-50%.

3. The immersion solution for auxiliary materials in industrial silicon production according to claim 1, characterized in that: The concentration of the sodium silicate solution is 20%-55%.

4. A method for preparing an auxiliary material for industrial silicon production, characterized in that, It includes the following steps: Step 1, by weight, each 100 parts of soaking solution includes 10-35 parts of silica powder, 5-20 parts of silica sol, 5-20 parts of sodium silicate solution, 0-1 part of methylcellulose, 0-1 part of starch, 0-1 part of silane coupling agent; the balance is water. Step 2: Soak the excipients from the previous step in the soaking solution at room temperature for 3 minutes to 3 hours; Step 3: Sieve and drain the excipients soaked in Step 2 to obtain the excipients for industrial silicon production.

5. A method for preparing an auxiliary material for industrial silicon production according to claim 4, characterized in that, The auxiliary material is granular coal or wood chips.

6. An auxiliary material for industrial silicon production obtained by the manufacturing method according to any one of claims 4-5, characterized in that: The term includes granular coal or wood chips that have been treated with a soaking solution.

Images