Waste silicon wafer-cutting fluid processing method and silicon carbide rinsing device

Abstract

The invention discloses a waste silicon wafer-cutting fluid processing method and a silicon carbide rinsing device. The processing method includes the following steps that: (A) water is added to dilute waste silicon wafer-cutting fluid and mixed, and a magnet is used for attracting iron; (B) flocculant is added, and solid and liquid are separated; (C) water is added to dilute the solid, and the silicon carbide suspension is added with sodium hydroxide, heated for reaction, washed by water, added with acid and washed until the pH value reaches 6.5 to 7, so that a crude silicon carbide product is obtained; (D) the crude product is separated, and after drying, a finished silicon carbide product is obtained; (E) the liquid is filtered, and after dehydration, a finished polyethylene glycol product is obtained. The scheme increases the purity of the sodium carbide, and reduces the consumption of acid and alkaline. The silicon carbide rinsing device comprises a rinsing bucket, the sidewall of the rinsing bucket is provided with a plurality of decanting outlets, the end of the rinsing bucket is provided with a water inlet tube, and a water distributor is arranged in the cone; the wall of the rinsing bucket is also provided with an air inlet, and an air tube is arranged in the bucket, and is provided with a plurality of microporous air distributors. The device can prevent the sediment of silicon carbide, thus enhancing the rinsing effect.

Description

technical field [0001] The invention relates to a method for recycling waste liquid and a silicon carbide rinsing device, more specifically to a method for recovering polyethylene glycol and silicon carbide from silicon crystal cutting waste liquid and a silicon carbide rinsing device in the method. Background technique [0002] In the process of multi-wire cutting of silicon wafers, the functions of cutting fluid are mainly to disperse, suspend, lubricate, cool, improve cutting efficiency, and reduce cutting consumption. The main components of existing silicon wafer cutting fluids are polyethylene glycol and silicon carbide, so the main components of the cutting waste liquid produced by silicon wafer cutting are polyethylene glycol and silicon carbide, and also include a small amount of silicon chips (generally 2-2 5%) and traces of metallic iron. The existing recovery of polyethylene glycol and silicon carbide in silicon crystal cutting waste liquid often has problems suc...

AI Technical Summary

Problems solved by technology

This method is easy to control, simple equipment, and low cost, but its existing problems are: one is that silicon carbide and silicon cannot be effectively separated; the other is that HNO 3 The mixed acid treatment method composed of +HF is likely to cause fluorine pollution;

[0004] The above process needs to be further improved. If the polyethylene glycol is to be evaporated, the temperature should be about 200°C under vacuum conditions. At this time, the polyethylene glycol has deteriorated and turned red, losing its use value.

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