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Method for recovering silicon carbide in waste cutting mortar by using ammonium bifluoride

A technology of ammonium bifluoride and cutting waste sand, which is applied in the fields of monocrystalline silicon or polycrystalline silicon processing, environment and chemical industry, can solve the problem that waste mortar cannot be processed in a timely and effective manner, achieve obvious economic and social benefits, and is simple to operate and easy to process. Achieve the effect of industrialization

Inactive Publication Date: 2011-08-31
TARIM UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

At present, there is such a problem in both the solar photovoltaic industry and the electronic semiconductor industry: With the increase in the demand for cutting fluid and abrasives for cutting silicon wafers by silicon wafer manufacturers, a large amount of waste mortar produced during the cutting process cannot be processed in a timely and effective manner.
Among them, in the off-line recovery process, the physical method has the advantages of small energy loss in the treatment process, simple operation, simple process, low equipment cost, and easy industrialization. It has been widely used in industry and is also the focus of current research; chemical method through the conversion of raw materials , the new product made simultaneously recovers silicon carbide materials, the recovery of materials has high purity, and has certain potential, but further research work is still needed

Method used

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  • Method for recovering silicon carbide in waste cutting mortar by using ammonium bifluoride
  • Method for recovering silicon carbide in waste cutting mortar by using ammonium bifluoride

Examples

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Embodiment 1

[0019] During the silicon wafer processing of substrates such as solar cells or integrated circuits (semiconductors and liquid crystal displays, etc.), the waste mortar generated is pretreated to remove oil-based dispersants (such as polyethylene glycol, etc.) and a small amount of impurities (such as iron etc.), put 30 kg of sand powder (silicon carbide 86.6%, silicon 13.4%) into the container after pretreatment, and add 13 kg of ammonium bifluoride, stir evenly, add water to disperse and dissolve ammonium bifluoride gradually while reacting, to avoid becoming solid Shape, react at 50°C for 1.2 hours, add about 100 g of deionized distilled water to dissolve the reaction product ammonium fluorosilicate, control the concentration close to the saturated concentration, filter and separate, wash the solid three times to obtain 27.8 kg of wet silicon carbide, and pass through Dry to obtain finished silicon carbide; add 0.5 kg of large-grained high-purity silicon to the filtrate and ...

Embodiment 2

[0021] During the silicon wafer processing of substrates such as solar cells or integrated circuits (semiconductors and liquid crystal displays, etc.), the waste mortar generated is pretreated to remove oil-based dispersants (such as polyethylene glycol, etc.) and a small amount of impurities (such as iron etc.), put 30 kg of pretreated sand powder (silicon carbide 82.1%, silicon 17.9%) into the container, and add 17.5 kg of ammonium bifluoride, stir evenly, gradually add water to disperse and dissolve ammonium bifluoride while reacting, to avoid solidification Shape, react at 60°C for 1 hour, add deionized distilled water at about 100°C to dissolve the reaction product ammonium fluorosilicate, control the concentration close to the saturated concentration, filter and separate, and wash the solid three times to obtain 26.3 kg of wet silicon carbide. After drying, the finished silicon carbide is obtained; 0.5 kg of large-grained high-purity silicon is added to the filtrate and w...

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Abstract

The invention discloses a method for recovering silicon carbide in waste mortar generated in a process for cutting monocrystalline silicon and polycrystalline silicon rods or processing silicon chips by using ammonium bifluoride, which comprises the steps of: dissolving silicon in preprocessed waste mortar by using an ammonium bifluoride solution, adding water for dissolving to ensure that the silicon forms a solution, and filtering to obtain the silicon carbide as a target product; carrying out low-temperature crystallization on the generated ammonium fluosilicate solution, and filtering to obtain an ammonium fluosilicate product; and dissolving the ammonium fluosilicate with a crystallized water solution, and repeatedly using the ammonium fluosilicate. All components are reasonably utilized in the whole process without wastewater emission and secondary pollution, and requirements for a green chemical process are met. The invention has the advantages of higher reaction rate, milder process conditions, low equipment investment, simpleness in operation, easiness in industrialization, and remarkable economic benefit and social benefit.

Description

technical field [0001] The invention relates to waste materials produced by industries such as monocrystalline silicon or polycrystalline silicon rod processing or silicon wafer cutting, such as solar energy and semiconductor industries, specifically including the fields of monocrystalline silicon or polycrystalline silicon processing, environment and chemical industry. Background technique [0002] Wire cutting waste mortar is a kind of waste generated during the wire cutting process of high-purity monocrystalline silicon and polycrystalline silicon rods during the processing of silicon wafers. It mainly comes from substrates for integrated circuits, solar cell substrates, electronic chips, and precision semiconductors. Chips in the multi-wire cutting process of thin sheet products. The main components of wire cutting waste mortar include silicon carbide SiC, polyethylene glycol (PEG) or oil-based suspension, silicon Si and iron Fe, etc. Among them, SiC, PEG and Si are all...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C01B31/36
Inventor 田维亮白红进刘文杰李治龙卢亚玲
Owner TARIM UNIV
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