Recovery of silicon carbide using potential floatation for silicon slurry

Hsun Chi Li, Wei-sheng Chen

Research output: Contribution to conferencePaperpeer-review

Abstract

According to the present statistics, Taiwan produces approximately 20,000 tons of silicon slurry annually from the solar industry. During the silicon wafer slicing process, it will produce solid part about 40 %∼50 % (SiC carbide, Si and metal fragments) and glycol 50 %∼60 % (DEG, PG and PEG). Most of the silicon slurry are landfilled or incinerated without recycling as a waste of resources. Silicon carbide and silicon in the silicon slurry can both be recycled, and the costs will also be reduced. The purpose of this study is to recycle high purity silicon carbide from the silicon slurry. Various techniques have been proposed to separate and recover the silicon carbide. Physical separation such as heavy liquid and centrifugation separation is a simply method to separate silicon slurry, but unable to obtain a high purity silicon carbide. Chemical separation such as cleaning with acid takes a lot of chemical agents and causes higher cost. The flotation separation is the cost-effective to recover high purity silicon carbide. We used oxidation reduction potential as the parameter which affected flotation and controlled this potential to find out best recovery rate and minimum amount of agent in this study. There are two advantages in this technique, one is lower amount of chemical agent and the other is to obtain high purity silicon carbide. The result of this study, the optimum oxidation reduction potential section is 100mV∼200mV, amount of chemical agent is 12.6%, silicon carbide recovery rate is 48.6%, silicon carbide grade 98.0%.

Original languageEnglish
Pages673-680
Number of pages8
Publication statusPublished - 2015 Jan 1
Event13th International Symposium on East Asian Resources Recycling Technology, EARTH 2015 - Pattaya, Thailand
Duration: 2015 Nov 12015 Nov 4

Other

Other13th International Symposium on East Asian Resources Recycling Technology, EARTH 2015
CountryThailand
CityPattaya
Period15-11-0115-11-04

All Science Journal Classification (ASJC) codes

  • Environmental Science(all)

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