Method for recovering polysilicon ingots, carborundum powder and polyethylene glycol from cutting waste mortar

A technology for cutting waste sand and polyethylene glycol, applied in chemical instruments and methods, silicon compounds, inorganic chemistry, etc., can solve the problems of high content and affect the conversion efficiency of photovoltaic cells, and achieve the effect of high yield

Inactive Publication Date: 2010-08-04
唐康宁
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

However, the content of impurities in silicon obtained by this method, especially phosphorus, is still relatively high, thus affecting the conversion efficiency of the photovoltaic cell produced

Method used

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  • Method for recovering polysilicon ingots, carborundum powder and polyethylene glycol from cutting waste mortar
  • Method for recovering polysilicon ingots, carborundum powder and polyethylene glycol from cutting waste mortar
  • Method for recovering polysilicon ingots, carborundum powder and polyethylene glycol from cutting waste mortar

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Experimental program
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Effect test

Embodiment 1

[0027] The composition of waste mortar for wire cutting of solar silicon wafers is as follows: liquid polyethylene glycol accounts for 50% by weight, silicon carbide powder accounts for 42% by weight, silicon chips account for about 6.5% by weight, and metal chips account for about 1.5% by weight.

[0028] Take 100 kg of waste cutting mortar, and first carry out solid-liquid separation of the waste mortar through a plate and frame filter press, separate out 44 kg of liquid polyethylene glycol, and obtain 56 kg of sediment. After soaking and cleaning 56 kg of the obtained precipitate with acetone, 54 kg of the precipitate was obtained by centrifugation; the precipitate was washed with deionized water and dried to obtain 49 kg of powder, namely silicon powder, silicon carbide micropowder and metal particles mixed powder. The obtained mixed powder is dispersed by the jet mill and put into the container, and the density is 2.5g / cm 3 In the tribromomethane alcohol heavy liquid, us...

Embodiment 2

[0032] The composition of waste mortar for wire cutting of solar silicon wafers is as follows: liquid polyethylene glycol accounts for 50% by weight, silicon carbide powder accounts for 42% by weight, silicon chips account for about 6.5% by weight, and metal chips account for about 1.5% by weight.

[0033] Take 100 kg of waste cutting mortar, first dilute the waste mortar and water with a ratio of 1:5 and then carry out solid-liquid separation on a hydrocyclone, and separate to obtain 56 kg of sediment and 264 kg of liquid polyethylene glycol aqueous solution. The liquid polyethylene glycol aqueous solution was heated to 100°C, and the water was evaporated to obtain 43kg polyethylene glycol.

[0034] Put 56kg of sediment into the container, soak it with acetone to remove oil and residual polyethylene glycol, and then centrifuge to obtain 53kg of sediment; wash the sediment with deionized water and dry to obtain 48kg of silicon powder, carbonization Mixed powder of silicon micr...

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Abstract

The invention discloses a method for recovering polysilicon ingots, carborundum powder and polyethylene glycol from cutting waste mortar. The recovering method comprises the following steps shown as an attached diagram, wherein the high temperature purification comprises the following steps of: mixing the prepared silicon micro powder with a fluxing agent according to the weight ratio of 1: 0.5-5 into lumps, carrying out high temperature treatment in a high temperature vacuum furnace with the treatment temperature range of 1450-1800 DEG C and the treatment time range of 1-10h; and then carrying out directional solidification on melting-state high purity silicon subjected to the high temperature treatment to obtain the polysilicon ingots; wherein the fluxing agent is selected from one or any mixture of silica, alumina, calcium oxide, magnesium oxide, potassium oxide, sodium oxide, calcium fluoride, magnesium fluoride, sodium fluoride, sodium chloride, potassium chloride and calcium chloride. The invention has the advantages that: the yields of carborundum and polyethylene glycol are high and can reach more than 70-80 percent; and the recovered polysilicon ingots reach the purity of 6-7N and completely satisfy of the requirement for preparing silicon slices of silicon solar cell.

Description

(1) Technical field [0001] The invention relates to a method for extracting high-purity silicon, silicon carbide powder and polyethylene glycol from waste liquid produced by cutting or grinding single crystal silicon or polycrystalline silicon ingots. (2) Background technology [0002] In the cost structure of solar cells, silicon wafers account for more than 35% of the cost. The solar multi-(single) crystal silicon wafer processing process generally goes through crystal growth, cutting, outer diameter rolling, flat edge, slicing, chamfering, grinding, corrosion, polishing, cleaning, packaging and other processes. Among them, silicon chip loss is generated in multiple cutting processes such as cutting head and tail, scraps, and slicing. In the silicon wafer cutting process, in order to reduce the mechanical stress and thermal stress and ensure the wire cutting process becomes a stable process, it is necessary to add a large amount of slurry cutting fluid, which is mainly co...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C01B33/037C01B31/36C02F9/02C08G65/34
Inventor 唐康宁
Owner 唐康宁
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