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Method for recovering silicon powder from cut mortar waste

A technology for cutting waste sand and silicon powder, which is applied in chemical instruments and methods, silicon compounds, inorganic chemistry, etc., can solve the problem that the purity of solar-grade silicon materials cannot be reached, and achieve the effect of simple process and controllable operation

Inactive Publication Date: 2014-12-03
佳明新材料科技有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

Chinese patent CN2010138035 discloses "Recycling and processing method of silicon wafer cutting waste mortar", in which the content of recycled silicon powder involved is only 90%, and its purity is far below the requirements of solar-grade silicon materials

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0015] The wire cutting waste mortar is composed (weight%): 45% of PEG, 6.5% of silicon powder, 46.6% of silicon carbide abrasive grains, 1.5% of metal, and 0.4% of unknown substances. Take 1 ton of waste cutting mortar.

[0016] (1) Solid-liquid separation process: first carry out solid-liquid separation of wire cutting waste mortar to obtain 542 kg of solid mixture, and the filtrate is circulated to the cutting fluid for recycling; carbon disulfide ethanol solution (2% by weight) is added to the solid mixture for stirring Dilute, wash to remove suspended impurities, filter, wash with ethanol, and filter again to obtain 535kg of mixed sand powder, and the washing liquid is collected and recycled for reuse;

[0017] (2) Magnetic separation and separation process: the obtained mixed sand powder is subjected to magnetic separation and separation to remove iron and iron oxides and iron-based metal impurities containing various alloying elements such as Cr, Ni, Ti, Mn, etc., to ob...

Embodiment 2

[0021] The wire cutting waste mortar is composed (weight%): 45% of PEG, 6.5% of silicon powder, 46.6% of silicon carbide abrasive grains, 1.5% of metal, and 0.4% of unknown substances. Take 1 ton of waste cutting mortar.

[0022] (1) Solid-liquid separation process: first carry out solid-liquid separation of wire cutting waste mortar to obtain 542 kg of solid mixture, and circulate the filtrate to the cutting fluid for recycling; add carbon disulfide ethanol solution (5% by weight) to the solid mixture and stir Dilute, wash to remove suspended impurities, filter, wash with ethanol, and filter again to obtain 534.6 kg of mixed sand powder, which is collected and recycled for reuse;

[0023] (2) Magnetic separation and separation process: the obtained mixed sand powder is subjected to magnetic separation and separation to remove iron and iron oxides and iron-based metal impurities containing various alloying elements such as Cr, Ni, Ti, Mn, etc., to obtain Mixture of silicon po...

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Abstract

The invention discloses a method for recovering silicon powder from cut mortar waste. According to the adopted technical scheme, the method comprises the following steps of: carrying out solid-liquid separation on the cut mortar waste to obtain a solid mixture, and adding an ethanol solution of carbon bisulfide to wash away suspended impurities to obtain mixed sand powder; carrying out magnetic separation on the obtained mixed sand powder to remove iron, iron oxides and metal impurities; carrying out acid cleaning; carrying out solution floatation and gravity separation to recover suspended matters, then washing the suspended matters by using ethanol, and drying to obtain high-purity silicon powder. The method disclosed by the invention effectively integrates the silicon powder recovery process through the steps of a solid-liquid separation procedure, a magnetic separation procedure, an acid cleaning procedure, a solution floatation procedure and the like, thus achieving the advantages of simple process, operation controllability, excellent economical performance and no secondary pollution. According to the method for recovering the silicon powder from the cut mortar waste, the recovery rate of silicon powder is higher than 80%, the content of silicon powder monomers is higher than 99%, and the silicon powder can be used as a raw material of a solar silicon wafer and is suitable for industrial popularization and application.

Description

Technical field: [0001] The invention relates to the field of solar silicon chip cutting, in particular to a method for recovering silicon powder from cutting waste mortar. Background technique: [0002] With the reshuffle of the solar silicon wafer cutting industry and the continuous decline in profits, silicon wafer cutting companies have invariably played the card of controlling the production process and reducing production costs. The most direct is the recycling of cutting fluid and silicon carbide micropowder among the three major auxiliary materials. [0003] Solar cells are generally produced by multi-wire sawing with mortar cutting. The mortar used in wire cutting is usually made of mineral oil or polyethylene glycol (PEG) and other media with a certain viscosity mixed with SiC abrasive powder; wire saw wire The diameter is generally 0.18mm, and the resulting kerf width is generally 0.2-0.3mm, while the thickness of the current solar cell silicon wafer is 0.18-0.22...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C01B33/037
Inventor 王允佳戴道军
Owner 佳明新材料科技有限公司
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