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

A treatment method, silicon carbide technology, applied in the direction of silicon carbide, carbide, etc., can solve the problems of ineffective separation of silicon carbide and silicon, fluorine pollution, loss of use value, etc., to achieve mature and reliable production process, high recovery rate, and treatment low cost effect

Inactive Publication Date: 2010-10-13
ZHEJIANG YUANSHENG SILICON MATERIALS
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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

Method used

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

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0039] Take 50 kg of silicon crystal cutting waste liquid, add 50 kg of water, stir, the mixture is ultrasonically treated, and the iron in the mixture is sucked out with a magnet; 0.03 kg of flocculant is added, and after the reaction, a centrifuge is used for solid-liquid separation to obtain a solid and liquid.

[0040] Take 10 kg of solid matter, add 10 kg of water to dilute it into a silicon carbide suspension, add a mass percent concentration of 30% sodium hydroxide solution to the suspension until the pH value is 12, heat to 80°C for reaction, and after the reaction is completed, Washing with water until the pH value reaches 7.5, then adding a 30% mass percent sulfuric acid solution until the pH value is 3, washing with water until the pH value reaches 7, and obtaining a crude silicon carbide. A scraper centrifuge is used for separation, and the separated solid is heated and dried until the water content is not more than 0.4%, and the silicon carbide product is obtained...

Embodiment 2

[0043]Take 50 kg of silicon crystal cutting waste liquid, add 100 kg of water, stir, the mixture is ultrasonically treated, and the iron in the mixture is sucked out with a magnet; 0.05 kg of flocculant is added, and after the reaction, a centrifuge is used for solid-liquid separation to obtain a solid and liquid.

[0044] Take 10 kg of solid matter, add 15 kg of water to dilute it into a silicon carbide suspension, add a mass percent concentration of 40% sodium hydroxide solution to the suspension until the pH value is 11, and heat to 90°C for reaction. After the reaction is completed, Washing with water until the pH value reaches 7, then adding a 25% hydrochloric acid solution by mass percentage until the pH value is 1, washing with water until the pH value reaches 6.5, and obtaining a crude silicon carbide. A scraper centrifuge is used for separation, and the separated solid is heated and dried until the water content is not more than 0.5%, so as to obtain a finished silico...

Embodiment 3

[0047] Take 50 kg of silicon crystal cutting waste liquid, add 25 kg of water, stir, the mixture is ultrasonically treated, and the iron in the mixture is sucked out with a magnet; 0.01 kg of flocculant is added, and after the reaction, a centrifuge is used for solid-liquid separation to obtain a solid and liquid.

[0048] Take 10 kg of solid matter, add 5 kg of water to dilute it into a silicon carbide suspension, add a mass percent concentration of 10% sodium hydroxide solution to the suspension until the pH value is 13, heat to 60°C for reaction, and after the reaction is completed, Washing with water until the pH value reaches 7, then adding a 20% sulfuric acid solution by mass percentage until the pH value is 4, washing with water until the pH value reaches 7, and obtaining a crude silicon carbide. A scraper centrifuge is used for separation, and the separated solid is heated and dried until the water content is not more than 0.3%, so as to obtain a finished silicon carbi...

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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...

Claims

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Application Information

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IPC IPC(8): C01B31/36C08G65/34C01B32/956
Inventor 罗其洋陈云根
Owner ZHEJIANG YUANSHENG SILICON MATERIALS
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