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A kind of recycling method of silicon wafer cutting waste mortar

A recycling method, silicon wafer cutting technology, applied in chemical instruments and methods, silicon compounds, inorganic chemistry, etc., can solve the problems of separation process human and environmental hazards, incomplete separation of silicon and silicon carbide, etc., to achieve a simple and controllable process Effect

Active Publication Date: 2011-12-28
BYD CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0006] The invention solves the technical problems in the prior art that the separation of silicon and silicon carbide is not complete, and the separation process is harmful to people and the environment

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0030] The waste mortar was prepared according to the following composition: cutting fluid 44wt%, silicon carbide micropowder 48wt%, silicon powder 6.8wt%, metal particles 1.2wt%.

[0031] (1) 10Kg of waste mortar was centrifuged at a speed of 1400rpm for 40min to obtain liquid and solid sand materials. Add 440g of polyacrylamide and 440g of diatomaceous earth to the liquid, stir evenly and then centrifugally filter at a speed of 1400rpm, collect the filtrate and weigh 4.2kg, then add 440g of activated carbon as a decolorizing agent, stir evenly and centrifugally filter at a speed of 1400rpm, The polyethylene glycol obtained from the filtrate was collected and weighed.

[0032] (2) Clean the solid sand material with deionized water and dry it; pass the sand material through a magnetic separator to remove the metal in the sand material to obtain a mixture of silicon and silicon carbide.

[0033](3) Pour the mixture of silicon and silicon carbide in step (2) into a quartz cruci...

Embodiment 2

[0038] Waste mortar was prepared according to the composition of Example 1: cutting fluid 44wt%, silicon carbide micropowder 48wt%, silicon powder 6.8wt%, metal particles 1.2wt%.

[0039] (1) 10Kg of waste mortar was centrifuged at a speed of 2000rpm for 30min to obtain liquid and solid sand materials. Add 440g of polyacrylamide and 440g of diatomaceous earth to the liquid, stir evenly and then centrifugally filter at a speed of 2000rpm, collect the filtrate and weigh 3.9kg, then add 440g of activated carbon as a decolorizing agent, stir evenly and centrifugally filter at a speed of 2000rpm, The filtrate was collected to obtain polyethylene glycol and weighed.

[0040] (2) Clean the solid sand material with deionized water and dry it; pass the sand material through a magnetic separator to remove the metal in the sand material to obtain a mixture of silicon and silicon carbide.

[0041] (3) Pour the mixture of silicon and silicon carbide in step (2) into a quartz crucible with...

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PUM

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Abstract

The invention provides a method for recycling waste mortar for cutting silicon wafers, comprising the following steps: a. solid-liquid separation of waste mortar for cutting silicon wafers to obtain solid sand and liquid parts; b. adding decolorization to the liquid parts obtained in step a agent, ion adsorbent and filter aid, and solid-liquid separation to obtain polyethylene glycol cutting recovery liquid; c. the solid sand material obtained in step a is separated and removed by magnetic separation to obtain a mixture of silicon and silicon carbide; d. Heat the mixture of silicon and silicon carbide obtained in step c under vacuum at 1425-1550°C; cool to room temperature and filter through a sieve, collect the material under the sieve to obtain silicon carbide micropowder, collect the material on the sieve to obtain silicon block; pulverize silicon block to obtain silica fume. The recovery method provided by the invention is very environment-friendly, and the separation of silicon and silicon carbide is more thorough, and the recovered polyethylene glycol, silicon carbide and silicon powder have higher purity.

Description

technical field [0001] The invention relates to a method for recovering silicon chip cutting waste mortar. Background technique [0002] During the cutting process of single crystal Si and polycrystalline Si, the silicon powder produced when cutting silicon rods, broken silicon carbide particles, and metal powder produced after steel wire grinding are deposited into the mortar to form waste mortar, and its cutting performance is greatly reduced. Recycling waste mortar, extracting silicon powder, silicon carbide micropowder and polyethylene glycol, and reusing it can save energy and reduce waste. At present, the methods for recycling waste mortar mainly include (1) centrifugation: centrifugal separation to remove broken invalid silicon carbide abrasives and silicon powder in waste mortar; (2) chemical method: use acid / alkali and other chemicals to remove Silica fume and metal impurities. [0003] However, the separation efficiency of the centrifugal method is low, and the c...

Claims

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Application Information

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IPC IPC(8): C01B31/36C01B33/021C08G65/34
Inventor 陈帆王忠利林宏业
Owner BYD CO LTD
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