A method for recovering high-purity silicon and silicon carbide from crystalline silicon cutting waste

A technology for cutting waste and silicon carbide, which is applied in the direction of silicon carbide, chemical instruments and methods, carbide, etc., can solve the problems of unsatisfactory recovery of high-purity silicon, no industrialization reports, and difficult separation, so as to increase production rate and consumption Low, Enhanced Effects

Active Publication Date: 2020-09-25
HEFEI INSTITUTES OF PHYSICAL SCIENCE - CHINESE ACAD OF SCI
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0014] From the current recycling situation, it can be seen that the comprehensive recycling of cutting waste has made great progress, but the recovery of high-purity silicon is not ideal, because some physical properties of silicon and silicon carbide are similar, and separation is difficult
In addition, the most valuable component in cutting waste is silicon, which has a relatively high content. In order to effectively recycle silicon and improve the utilization rate of resources, some researchers at home and abroad have carried out related research and exploration, and the research has also achieved certain results. However, No industrialization report

Method used

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  • A method for recovering high-purity silicon and silicon carbide from crystalline silicon cutting waste
  • A method for recovering high-purity silicon and silicon carbide from crystalline silicon cutting waste
  • A method for recovering high-purity silicon and silicon carbide from crystalline silicon cutting waste

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0047] (1) Pretreatment of slurry

[0048] Mix 15g of crystalline silicon cutting waste with 150mL of absolute ethanol solution to form a suspension system, stir at room temperature and pressure for 2 hours, wash the obtained suspension with water and suction filter, and then filter and dry to obtain silicon and silicon carbide. dry mix;

[0049] (2) High temperature treatment

[0050] Place the dry mixture of silicon and silicon carbide obtained after pretreatment in a heating furnace, first vacuumize it, then pass in argon, raise the temperature to 500 ° C, keep the temperature for 1 hour, and then cool it to room temperature to obtain high temperature treated silicon and silicon carbide mixture;

[0051] (3) pickling treatment

[0052] Mix the high-temperature-treated silicon and silicon carbide mixture with 2mol / L sulfuric acid solution, control the reaction temperature at 60°C, and the reaction time for 4 hours. After the reaction is completed, filter, wash and dry the...

Embodiment 2

[0057] (1) Pretreatment of slurry

[0058] Mix 15g of crystalline silicon cutting waste with 200mL of acetone solution to form a suspension system, stir at room temperature and pressure for 3 hours, wash the obtained suspension with water and suction filter, then filter and dry to obtain a dry mixture of silicon and silicon carbide material;

[0059] (2) High temperature treatment

[0060] Place the dry mixture of silicon and silicon carbide obtained after pretreatment in a heating furnace, first vacuumize it, then pass in argon gas, raise the temperature to 450 ° C, keep the temperature for 1 hour, and then cool to room temperature to obtain high temperature treated silicon and silicon carbide mixture;

[0061] (3) pickling treatment

[0062] Mix the high-temperature-treated silicon and silicon carbide mixture with 2mol / L sulfuric acid solution, control the reaction temperature at 60°C, and the reaction time for 4 hours. After the reaction is completed, filter, wash and dr...

Embodiment 3

[0067] (1) Pretreatment of slurry

[0068] Mix 15g of crystalline silicon cutting waste with 150mL of absolute ethanol solution to form a suspension system, stir at room temperature and pressure for 2 hours, wash the obtained suspension with water and suction filter, and then filter and dry to obtain silicon and silicon carbide. dry mix;

[0069] (2) High temperature treatment

[0070] Put the dry mixture of silicon and silicon carbide obtained after pretreatment in a heating furnace, first vacuumize it, then pass in hydrogen gas, raise the temperature to 450 ° C, keep the temperature for 1 hour, and then cool to room temperature to obtain silicon and silicon carbide after high temperature treatment Silicon carbide mixture;

[0071] (3) pickling treatment

[0072] Mix the high-temperature-treated silicon and silicon carbide mixture with 1mol / L sulfuric acid solution, control the reaction temperature at 60°C, and the reaction time for 4 hours. After the reaction is completed...

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Abstract

The invention discloses a method for recovery of high-purity silicon and silicon carbide from crystalline silicon cutting waste. The specific steps include: firstly, mixing silicon cutting waste withan organic solution, conducting stirring, filtering, washing and drying; then putting the dried silicon cutting waste in an atmosphere furnace for high temperature treatment, then conducting cooling to room temperature, mixing the silicon cutting waste with an acid solution, and performing washing, filtering and drying; and then putting the dried silicon cutting waste in a flotation tank, adding aflotation solution, adjusting the pH, starting a flotation machine for flotation, then carrying out filtering, washing and drying respectively on a floating material and a sinking material. The purity of silicon recovered by the method reaches 99.65% or above, and the purity of silicon carbide reaches 99.38% or above; the process is simple, feasible, environment-friendly and economical. The method provided by the invention simplifies the recovery process of crystalline silicon and silicon carbide, and reduces the amount of industrial solid waste, the adopted flotation reagent has the characteristics of no toxicity, no carcinogenicity and environmental friendliness, and high-valued recycling of resources is realized.

Description

technical field [0001] The invention belongs to the technical field of secondary resource utilization, in particular to a method for recovering high-purity silicon and silicon carbide from crystalline silicon cutting waste. Background technique [0002] With the aggravation of energy shortage and environmental pollution, solar energy has been paid more and more attention due to its clean, environmental protection and non-pollution characteristics, and is considered to be one of the important ways to solve the future energy crisis. At present, the raw materials used in solar photovoltaic power generation are mainly crystalline silicon materials, and a large amount of silicon cutting waste is generated during the cutting process of crystalline silicon wafers. At present, the crystalline silicon multi-wire cutting technology mainly includes the mortar cutting process and the diamond wire cutting process. Since the diameter of the cutting wire is similar to the thickness of the ...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C01B33/037C01B32/956
CPCC01B32/956C01B33/037
Inventor 李京伟陈健班伯源史剑
Owner HEFEI INSTITUTES OF PHYSICAL SCIENCE - CHINESE ACAD OF SCI
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