Recovery method for silicon carbide and polyethyleneglycol cutting fluids in waste cutting mortar for silicon wafer

Abstract

The invention provides a recovery method for silicon carbide and polyethyleneglycol cutting fluids, which comprises the following steps: mixing waste cutting mortar for silicon wafer and water and performing second-stage solid and liquid separation, diluting first-stage solid particles with water, then performing second-stage solid and liquid separation, reusing the second-stage suspension liquid for mixing, performing first-stage water wash on the second stage solid particles, then performing third-stage centrifugal separation, reusing the third-stage centrifugal separation liquid for dilution, performing second-stage water wash on the third-stage centrifugal solid particles, then performing fourth-stage centrifugal separation, reusing the fourth-stage centrifugal liquid for first-stage water wash, drying and screening the fourth-stage centrifugal solid particles to obtain silicon carbide, performing filtration, decoloration and resin exchange on the first-stage suspension liquid, and performing reduced pressure distillation and thin film evaporation in sequence to acquire the polyethyleneglycol cutting fluid, the reduced pressure distillation water and the thin film evaporation water, wherein the reduced pressure distillation water is used for the second-stage water wash, and the thin film evaporation water is used for the first-stage water wash. The recovery method remarkably reduces the pollution degree of the sewage, and is beneficial to environment protection.

Description

technical field [0001] The invention relates to the technical field of silicon wafer cutting, in particular to a method for recovering silicon carbide and polyethylene glycol cutting fluid in silicon wafer cutting waste mortar. Background technique [0002] Silicon wafers are the main production material in industries such as semiconductors and solar energy, and are usually obtained by cutting silicon rods. In the process of cutting silicon rods, the cutting mortar is often composed of silicon carbide and polyethylene glycol cutting fluid, so silicon carbide and polyethylene glycol cutting fluid are included in the silicon wafer cutting waste mortar. If the silicon wafer cutting waste mortar is directly discarded, it will not only pollute the environment, but also cause waste of components such as silicon carbide and polyethylene glycol cutting fluid, and increase production costs. Therefore, the silicon carbide and polyethylene glycol in the silicon wafer cutting waste mort...

AI Technical Summary

Problems solved by technology

This recovery method still produces a large amount of sewage with a relatively serious environmental pollution during the recovery process, and the quality of the recovered product is still unstable, which affects its application.

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