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Method for recycling silicon from filings obtained through silicon wafer cutting

A silicon chip cutting and sawdust technology, applied in the direction of silicon, silicon carbide, carbide, etc., can solve the problems of poor effect, long time-consuming, easy to agglomerate, etc., and achieve short time-consuming, high purity and high separation efficiency Effect

Active Publication Date: 2013-07-10
ZHEJIANG UNIV +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

However, the silicon carbide particles and silicon particles in the waste mortar are all in the micron or even nano-scale, and are prone to agglomeration under the charge attraction and surface interaction. Some nano-scale particles are also suspended in the solution and difficult to settle, while silicon carbide The difference in density with silicon is also small, and gravity flotation alone takes a long time and the effect is not good

Method used

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  • Method for recycling silicon from filings obtained through silicon wafer cutting
  • Method for recycling silicon from filings obtained through silicon wafer cutting

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0021] Mix 100g of cutting sawdust and deionized water, adjust the solid-liquid ratio to 1:20, add ethyl acetate as a dispersant to form a suspension, and ultrasonically clean the suspension for 600 minutes. After the treatment is completed, centrifuge the suspension, and repeat the above steps. The cleaning process was performed 5 times to obtain muddy solids.

[0022] Put the muddy solid content into hydrochloric acid (mass fraction 37%), nitric acid (mass fraction 65%), hydrofluoric acid solution (mass fraction 40%) in sequence, adjust the solid-liquid ratio to be 1: 20, under the action of stirring Pickling treatment for 600 minutes respectively, after the treatment, the product was rinsed with deionized water or distilled water several times to obtain a mixture of silicon carbide and silicon.

[0023] The configuration density is 3.2g / cm 3 The centrifuge solvent tribromomethane alcohol solution, put the mixture of silicon carbide and silicon into the solution, and then c...

Embodiment 2

[0027] Cutting sawdust and deionized water were mixed with a solid-to-liquid ratio of 1:2, and the rest of the conditions were the same as in Example 1. There are weak silicon carbide peaks in the XRD spectrum of the high-purity silicon powder sample obtained in this example, indicating that the obtained sample contains a very small amount of silicon carbide.

Embodiment 3

[0029] The ultrasonic cleaning treatment time of the suspension was 5 minutes, and the other conditions were the same as in Example 1. There are weak silicon carbide peaks in the XRD spectrum of the high-purity silicon powder sample obtained in this example, indicating that the obtained sample contains a very small amount of silicon carbide.

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Abstract

The invention discloses a method for recycling silicon from filings obtained through silicon wafer cutting. The method comprises the steps of: mixing the filings with water, respectively regulating a solid-liquid weight ratio to be 1:2-1:20, adding a dispersing agent to form a suspension, carrying out ultrasonic cleaning and solid-liquid separation on the suspension to obtain muddy solid containing matters; sequentially adding the muddy solid-containing matters into a hydrochloric acid solution, a nitric acid solution and a hydrofluoric acid solution, regulating a solid-liquid weight ratio tobe 1:2-1:20, acid-washing, then rinsing to obtain a silicon and silicon carbide mixture; and adding the silicon and silicon carbide mixture into a centrifugal solvent with the density being between density values of silicon and silicon carbide, centrifugally separating, purifying and drying to obtain silicon powder and silicon carbide powder. The method provided by the invention is convenient foroperation, high in separation efficiency, short in time consumption, low in cost and high in purity of recycled silicon.

Description

technical field [0001] The invention relates to the technical field of recovery of waste mortar, in particular to a method for recovering silicon from silicon chip cutting sawdust. Background technique [0002] With the development of the economy and the continuous improvement of people's living standards, the society's demand for energy is increasing day by day. With the depletion of conventional energy and the increasing awareness of environmental protection, the development and utilization of renewable energy has attracted a lot of attention. Solar energy is considered to be the best alternative energy source for human beings in the future, and it is inexhaustible. In the effective use of solar energy, large solar power generation (photovoltaic) is the fastest growing and most dynamic development direction in recent years. It has no noise, no emissions, and no environmental pollution, making it the most sustainable renewable energy technology. Among all kinds of solar ...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C01B33/02C01B31/36C01B32/956
Inventor 汪雷谷硕实李东升杨德仁王谊景超
Owner ZHEJIANG UNIV