Recovery of silicon, copper and aluminum from scrap silicon wafers by leaching and precipitation

Ching Hwa Lee, Ying Wen Chang, Srinivasa R. Popuri, Chi En Hung, Ching Hua Liao, Juu-En Chang, Wei-sheng Chen

Research output: Contribution to journalArticle

1 Citation (Scopus)

Abstract

The Silicon wafer plays an important role in modern electronic products. During the production of Silicon wafer, a large amount of scrap Silicon wafer is generated. The necessity for it to be recycled and recovered is of vast importance since the metal Silicon (Si) is the major by product. Besides Silicon, the wafers also contain a small quantity of Copper (Cu) and Aluminum (Al), that are considered as minor elements during the recovery process of the Silicon wafer production. Therefore, in order to conserve limited natural resources, minimize pollution problems and recover the valuable resource of Silicon from scrap wafer, a leaching method was adopted in this study. Physical and chemical methods such as screening and leaching processes were employed to investigate the recovery of Silicon and other metals from scrap wafers. The leaching process was carried out with three leaching reagents such as HCl, HNO3 and H2SO4. Batch studies were also conducted to optimize the leaching operating conditions with consideration to the leaching time, the concentration of leaching reagent, temperature and solid/liquid ratio. The result of the leaching tests revealed that the Copper and Aluminum contained in the scrap wafers can be 100% leached and removed by using 5N HNO3 under the conditions of two hours leaching time, 5g/50 mL of solid/liquid ratio, and 70℃ temperatures. After leaching with Nitric acid, a high purity of Silicon was obtained and could be reused as the feed material for the production of Silicon wafer. The Copper and Aluminum remaining in the leaching solution was recovered through precipitation by adjusting its’ pH to 11 and 7 to form Cu (OH)2 and Al(OH)3, respectively.

Original languageEnglish
Pages (from-to)561-568
Number of pages8
JournalEnvironmental Engineering and Management Journal
Volume17
Issue number3
Publication statusPublished - 2018 Mar 1

Fingerprint

Silicon wafers
Leaching
silicon
aluminum
leaching
copper
Copper
Aluminum
Recovery
Silicon
physical method
liquid
metal
chemical method
Liquids
Natural resources
Nitric acid
nitric acid
Metals
Byproducts

All Science Journal Classification (ASJC) codes

  • Environmental Engineering
  • Pollution
  • Management, Monitoring, Policy and Law

Cite this

Lee, Ching Hwa ; Chang, Ying Wen ; Popuri, Srinivasa R. ; Hung, Chi En ; Liao, Ching Hua ; Chang, Juu-En ; Chen, Wei-sheng. / Recovery of silicon, copper and aluminum from scrap silicon wafers by leaching and precipitation. In: Environmental Engineering and Management Journal. 2018 ; Vol. 17, No. 3. pp. 561-568.
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abstract = "The Silicon wafer plays an important role in modern electronic products. During the production of Silicon wafer, a large amount of scrap Silicon wafer is generated. The necessity for it to be recycled and recovered is of vast importance since the metal Silicon (Si) is the major by product. Besides Silicon, the wafers also contain a small quantity of Copper (Cu) and Aluminum (Al), that are considered as minor elements during the recovery process of the Silicon wafer production. Therefore, in order to conserve limited natural resources, minimize pollution problems and recover the valuable resource of Silicon from scrap wafer, a leaching method was adopted in this study. Physical and chemical methods such as screening and leaching processes were employed to investigate the recovery of Silicon and other metals from scrap wafers. The leaching process was carried out with three leaching reagents such as HCl, HNO3 and H2SO4. Batch studies were also conducted to optimize the leaching operating conditions with consideration to the leaching time, the concentration of leaching reagent, temperature and solid/liquid ratio. The result of the leaching tests revealed that the Copper and Aluminum contained in the scrap wafers can be 100{\%} leached and removed by using 5N HNO3 under the conditions of two hours leaching time, 5g/50 mL of solid/liquid ratio, and 70℃ temperatures. After leaching with Nitric acid, a high purity of Silicon was obtained and could be reused as the feed material for the production of Silicon wafer. The Copper and Aluminum remaining in the leaching solution was recovered through precipitation by adjusting its’ pH to 11 and 7 to form Cu (OH)2 and Al(OH)3, respectively.",
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Recovery of silicon, copper and aluminum from scrap silicon wafers by leaching and precipitation. / Lee, Ching Hwa; Chang, Ying Wen; Popuri, Srinivasa R.; Hung, Chi En; Liao, Ching Hua; Chang, Juu-En; Chen, Wei-sheng.

In: Environmental Engineering and Management Journal, Vol. 17, No. 3, 01.03.2018, p. 561-568.

Research output: Contribution to journalArticle

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AU - Lee, Ching Hwa

AU - Chang, Ying Wen

AU - Popuri, Srinivasa R.

AU - Hung, Chi En

AU - Liao, Ching Hua

AU - Chang, Juu-En

AU - Chen, Wei-sheng

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