Method for cleaning debris in monocrystal silicon wire-cut electrical discharge machining

Abstract

A method for cleaning debris in monocrystal silicon wire-cut electrical discharge machining relates to solar silicon washing techniques and comprises the following sequential steps: a, charging debris into a cleaning basket of pp, and soaking in HF (hydrofluoric acid); b, adding KOH into a cleaning tank, placing the basket holding the debris from monocrystal silicon wire-cut electrical discharge machining into an alkaline solution, stirring and cleaning with a polytetrafluoroethylene rod, and rinsing with purified water; c, preparing mixed liquid with HCL, HF and purified water, placing the basket holding the debris from monocrystal silicon wire-cut electrical discharge machining into the mixed liquid, stirring, cleaning and rinsing; d, adding purified water, heating to 40-50 DEG C, ultrasonically cleaning, transferring to a cleaning liquid, drying to obtain circulation tailing meeting the standard for ingot casting. The method has the advantages that for the debris from monocrystal silicon wire-cut electrical discharge machining, cutting waste liquid residue and metal impurity produced during cutting procedure are thoroughly removed by blending different chemical reagents via multiple cleaning, quality level of monocrystal debris is increased, ingot production cost is reduced, and feedable quantity of fragmented silicon is increased so that cost reduction and efficiency increasing are achieved.

Description

technical field [0001] The invention relates to the technical field of manufacturing solar single and polycrystalline silicon wafers, in particular to the washing technology of monocrystalline silicon wire-cut fragments. Background technique [0002] As the raw polycrystalline price of polysilicon ingot raw materials continues to decline, the cost of waste disposal such as wire-cut chips is relatively high; at present, HF+HNO3 mixed liquid pickling treatment or traditional alkali washing treatment is generally used in the market, and the cost of pickling treatment is relatively high. The cost of chemical reagents used for production and treatment per kilogram of waste is about 5 yuan, and the pressure on environmental protection is high. Although the cost of traditional alkaline cleaning treatment is low, the loss of silicon wafers is not easy to control. With the promotion of the diamond wire cutting process in the single crystal field, the single crystal market is bound to...

AI Technical Summary

Problems solved by technology

[0004] The object of the present invention is to provide a method for cleaning and treating monocrystalline silicon wire cutting fragments, which overcomes the defects of the existing processing technology, and has low processing cost and is suitable for the next process of casting ingots and putting them into furnaces.