Method for preparing high-purity silicon from silicon carbide sliced crystalline silicon waste mortar

A technology for cutting crystals and silicon carbide, applied in chemical instruments and methods, inorganic chemistry, silicon compounds, etc., can solve problems such as energy consumption, Si and SiC particle size intersection, furnace bottom rise, etc., and achieve strong adjustability and low price. , the effect of effective separation

Inactive Publication Date: 2018-10-19
HENAN XINDAXIN SCI & TECH +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

For example, using the difference in the melting points of Si and SiC to directly smelt silicon ingots, however, due to the high melting point of SiC, the content of SiC will cause the problem of furnace bottom rise
Using the low melting point of Si-Cu alloy, the melting temperature can be lowered, but the problem of rising the bottom of the furnace is still unsolved, and the separation of Si/Cu will also cause additional energy consumption
Using the difference of Zeta on the surface of Si and SiC to separate Si/SiC by electrophoresis; using the difference of con...

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0030] This example provides a method for preparing high-purity silicon from silicon carbide cut crystal silicon waste mortar, using silicon carbide cut crystal silicon waste mortar as a raw material, through crushing, purification, sorting, dehydration and drying, pressing, smelting, crushing, and purification , After drying, the product is made, the steps are as follows:

[0031] Step 1. Select the waste mortar of silicon carbide cutting crystalline silicon, and crush it to a particle size of <10 μm;

[0032] Step 2. Take 100 kg of waste mortar crushed in step 1, put it into a purification tank, add 200 kg of deionized water, and stir at a speed of 40-100 rpm, then add purified acid and start stirring until uniform, and then heat it to 30 After reacting at -100 degrees for 2-8 hours, neutralize to pH 4.5-7.5;

[0033] Step 3, add the slurry purified in step 2 into deionized water and stir evenly, and then the proportion of silicon carbide reaches the requirement after sorti...

Embodiment 2

[0054] Step 1. Select 300 kg of waste mortar of silicon carbide cutting crystalline silicon, and crush it to a particle size of <10 μm;

[0055] Step 2: Take 300 kg of waste mortar pulverized in step 1, put it into a purification tank, add 600 kg of deionized water, stir at a speed of 40-100 rpm, and then add one or more of sulfuric acid, hydrochloric acid, hydrofluoric acid, and nitric acid A combination, turn on the machine and stir until it is uniform, then heat it to 40 degrees with steam and react for 2-8 hours, then neutralize it to a pH of 4.5-7.5;

[0056] Step 3: Add 500 kg of deionized water to the slurry purified in Step 2, stir evenly, and then go through one or more combinations of air separation, cyclone separation, centrifugal separation, overflow separation and sedimentation separation. Optional, sample detection silicon carbide residual ratio is 8%;

[0057] Step 4, dehydrating and drying the slurry after step 3 sorting until the moisture content is less than...

Embodiment 3

[0072] Step 1. Select 300 kg of waste mortar of silicon carbide cutting crystalline silicon, and crush it to a particle size of <10 μm;

[0073] Step 2: Take 300 kg of waste mortar pulverized in step 1, put it into a purification tank, add 600 kg of deionized water, stir at a speed of 40-100 rpm, and then add one or more of sulfuric acid, hydrochloric acid, hydrofluoric acid, and nitric acid A combination, turn on the machine and stir until it is uniform, then heat it to 50 degrees with steam for 2-8 hours, then neutralize it to pH 4.5-7.5;

[0074] Step 3: Add 500 kg of deionized water to the slurry purified in Step 2, stir evenly, and then go through one or more combinations of air separation, cyclone separation, centrifugal separation, overflow separation and sedimentation separation. Optional, sample detection silicon carbide residual ratio is 10%;

[0075] Step 4, dehydrating and drying the slurry after step 3 sorting until the moisture content is less than 10%;

[0076...

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Abstract

The invention discloses a method for preparing high-purity silicon from silicon carbide sliced crystalline silicon waste mortar and belongs to the technical field of high-purity silicon preparation. The method comprises the following specific steps: 1, smashing a silicon carbide sliced crystalline silicon waste mortar raw material; 2, performing chemical processing and purification; 3, sorting; 4,utilizing a sheet frame to dewater the raw material and a bipyramid vacuum rotary drying machine to dry the raw material; 5, utilizing a pressing and forming machine to press the raw material in to blocks; 6, utilizing one or more combinations of an intermediate frequency furnace, an intermediate frequency electric arc furnace and an electromagnetic induction furnace to melt the raw material; 7,utilizing a breaking machine to smash the raw material; 8, utilizing one or more combinations of sulfuric acid, hydrochloric acid, hydrofluoric acid and nitric acid to perform purification and removeimpurities; 9, utilizing the bipyramid vacuum rotary drying machine to dry the raw material and drying to obtain a high-purity silicon product. The method disclosed by the invention can be used for purifying and recycling silicon powder in a mortar cutting waste material, the silicon powder is applied to a solar-grade silicon industry chain again, and great significance in resource reutilization,cost reduction and environmental protection is achieved.

Description

technical field [0001] The invention specifically relates to a method for preparing high-purity silicon by using silicon carbide cutting crystal silicon waste mortar, and belongs to the technical field of high-purity silicon preparation. Background technique [0002] In the production process of solar-grade crystalline silicon wafers, multi-line mortar cutting is a commonly used method. During the cutting process, the high-speed reciprocating motion of the metal wire is used to grind silicon carbide as the abrasive and polyethylene glycol as the dispersion and suspension agent. The silicon ingot can be cut into hundreds of pieces at the same time. With the accumulation of silica fume in the mortar, the cutting ability of the mortar gradually decreases and eventually becomes waste mortar that loses the cutting ability. The prior art can recycle the cutting fluid of the waste mortar and the SiC abrasive > 7mm, and the non-recyclable tailings are processed to obtain the mor...

Claims

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Application Information

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IPC IPC(8): C01B33/037
Inventor 王志王东杨正宏孙毅王昕晨宋中学辛玲曹明强冯勇涛翟路鹏王江龙
Owner HENAN XINDAXIN SCI & TECH
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