Method for recovering waste slurry of multiline cut silicon chips

Abstract

The invention discloses a method for recovering waste slurry of multiline cut silicon chips. The method comprises the following steps: recovered waste slurry is diluted by a cutting fluid to 20 to 25 percent of solid mass; particles of a silicon carbide blade material thicker than 6 microns are separated by a continuous centrifugal separation method; residue containing silicon carbide micro powder thinner than 6 microns and cutting fluid slurry of silicon micro powder are pressed into a filter mass by a presser; the filter mass is dried by microwave; the filter mass is subjected to a stage treatment of the silicon carbide micro powder and the silicon micro power by an air classifier; after the pressed cutting fluid and steam of the cutting fluid are filtered by a filter, residual impurities in the fluid is subjected to adsorption and impurity removal by floridin sorbent, and is filled and recovered through dehydration and decolorization. The method has the advantages that in the treatment on the waste slurry, the whole production process does not have any pollution, does not consume water, saves energy consumption over 70 percent, and has product recovery ratio over 98 percent.

Description

technical field [0001] The invention relates to the recycling of waste produced in the process of processing silicon wafers by adopting a multi-wire cutting method, in particular to a method for recycling waste slurry of multi-wire cutting silicon wafers. Background technique [0002] At present, the industrial production of photovoltaic cell silicon wafers and semiconductor silicon wafers adopts multi-wire cutting. The main consumables used in the production of multi-wire cutting are the slurry made of special cutting tools for silicon carbide wire cutting and polyethylene glycol cutting fluid. At the current technical level, 10-14 tons of silicon carbide special blades and 10-14 tons of cutting fluid are required to produce 1MW of solar-grade monocrystalline silicon wafers. For a long time, these used waste slurries (the main contents of which are silicon carbide, silicon micropowder, polyethylene glycol cutting fluid, metal impurities and water) have become a heavy burde...

AI Technical Summary

Problems solved by technology

For a long time, these used waste slurries (the main contents of which are silicon carbide, silicon micropowder, polyethylene glycol cutting fluid, metal impurities and water) have become a heavy burden on the silicon wafer cutting industry. Waste, and occupy space, pollute the environment