Method for recycling silicon powder from silicon slice cut waste mortar

A technology for cutting silicon wafers and cutting waste sand, which is applied in the direction of chemical instruments and methods, silicon, silicon compounds, etc., can solve the problems of recycling process, product purity is not high, solid-liquid separation is difficult, etc., to achieve strong applicability and save Alkali consumption, the effect of reducing raw material consumption

Inactive Publication Date: 2011-09-07
常州广正知识产权代理有限公司
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AI Technical Summary

Problems solved by technology

[0007] The purpose of the present invention is to overcome the common problems existing in the cutting waste mortar recycling industry, such as difficulty in solid-liquid separation, low purity of various recovered products, low comprehensive recovery rate, and the recovery process takes care of one and loses the other, and provides a method for cutting waste mortar from silicon wafers. A method for recovering silicon powder (polycrystalline silicon or monocrystalline silicon) from waste mortar. This method realizes the recovery of polycrystalline silicon or monocrystalline silicon while recycling polyethylene glycol and silicon carbide from the waste mortar for cutting silicon wafers, and improves solar energy manufacturing. The degree of renewable utilization of resources in the industry has met the requirements of clean production

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  • Method for recycling silicon powder from silicon slice cut waste mortar

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Experimental program
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Effect test

Embodiment 1

[0035] The silicon powder recovery test is being carried out by Jiangsu Creed Recycling Technology Co., Ltd.

[0036] The company used to only recycle polyethylene glycol and silicon carbide, and all the silicon powder in the cutting waste mortar was discarded. Combining the method described in the present invention with the company's previous production process, the front production process was adjusted, and the primary solid-liquid separation process was adjusted to secondary separation; at the same time, some key equipment and its auxiliary equipment were newly added or modified, Including precision filters, membrane separation equipment, flotation tanks, vacuum drying equipment, etc., a 600L / hour silicon powder recovery test production line has been built.

[0037] The process flow chart of the test is as follows figure 1 As shown, the specific situation is as follows:

[0038] The main components of the cutting waste mortar used in the test are: by weight percentage, 45...

Embodiment 2

[0048] Experiment of recovering polysilicon powder from the silicon-containing waste residue discarded by the online recovery system of Zhenjiang Dacheng New Energy Company.

[0049] The process flow chart of the test is as follows figure 1 As shown, the specific situation is as follows:

[0050] The main components of the silicon-containing waste residue used for the test are: by weight percentage, 24% polyethylene glycol solution, 16% silicon carbide, 57.6% polysilicon powder, and the rest are impurities.

[0051] Take 500kg of silicon-containing waste residue, add 200kg of recycled cutting fluid (from Jiangsu Kelide Recycling Technology Co., Ltd.) and 200kg of pure water as diluents, and mix thoroughly to form cutting waste mortar, which is continuously fed The method is injected into the centrifuge for solid-liquid separation, and the centrifugal force is 1200g; 100kg of solid precipitate (containing about 20% liquid content) and 800kg of silicon-containing liquid are obt...

Embodiment 3

[0059] The silicon powder recovery test was carried out in the pilot plant of Saipu (Wuxi) Membrane Technology Development Co., Ltd.

[0060] In order to systematically study the comprehensive utilization technology of silicon wafer cutting waste mortar, Saipu Company built a pilot plant. The scale of the pilot plant is 100kg / hour waste mortar treatment capacity, and it has both offline and online waste mortar recycling system features. Using the method of the present invention, the company obtained 200kg of waste mortar that had been placed for many years and was ready to be discarded from Hebei Fengqiang Company to carry out a silicon powder recovery test to explore whether the process of the present invention is suitable for the recycling of old stock waste mortar.

[0061] The details of the test are as follows:

[0062] The main components of the cutting waste mortar used in the test are: by weight percentage, 43% polyethylene glycol solution, 45% silicon carbide, 5% pol...

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Abstract

The invention relates to a method for recycling silicon powder from silicon slice cut waste mortar. The invention comprises seven procedural steps of solid-liquid separation of silicon slice cut waste mortar, precision separation of silicon-contained liquid, liquid flotation, precision filtering, film separation, pickling and vacuum drying. The method in the invention is used to produce silicon powder with a purity of 99.5-99.9% and solve the problems existing in the existing silicon slice cut waste mortar recycling industry, such as difficult separation between solid and liquid, low purity of recycled products, poor recycling rate, incomplete recycling process and the like. In the invention, the polyethylene glycol and carborundum can be recycled and the recycling of polycrystalline silicon and monocrystalline silicon can be realized, which improves the material recycling ratio of the solar equipment industry and come up to the cleanness standards.

Description

technical field [0001] The invention relates to a technology for comprehensive recycling of cutting waste mortar produced by silicon chip cutting or grinding in the solar energy industry and the electronic industry, in particular to a method for recycling silicon powder from the silicon chip cutting waste mortar. Background technique [0002] In the solar energy industry and the electronics industry, silicon wafers need to be cut, and silicon carbide micropowder with high hardness, small particle size and concentrated particle size distribution needs to be used as the main cutting medium in the cutting operation. In order to disperse the silicon carbide micropowder evenly during the cutting process, and take away the huge frictional heat generated during the cutting process in time, it is usually necessary to add the silicon carbide micropowder in a certain proportion to the polyethylene glycol (PEG) as the main raw material. Water-soluble silicon wafer cutting fluid, fully ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C01B33/02C01B33/037C10M175/00
Inventor 戴永琪戴臻宁李蕾
Owner 常州广正知识产权代理有限公司
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