Separation of gallium and arsenic in wafer grinding extraction solution using a supported liquid membrane that contains PC88A as a carrier.
Wafer grinding extraction solution was passed through a supported liquid membrane (SLM) that contained PC88A (2-ethylhexyl phosphonic acid mono 2-ethylhexyl ester) as a carrier, to separate gallium from arsenic by selective permeation. The SLM separation process was conducted under various conditions. The kind of membrane supporter, the pH of the feed, the feed concentration, and the HCl content in the strip governed the concentration of gallium and arsenic in the strip phase. The conditions determined as optimal in the laboratory test were used to perform the pilot test. Well separation between gallium and arsenic was performed in both laboratory and pilot tests. Hydrophobic membrane polytetrafluoroethylene (PTFE) with 0.2 microm pores was the best of three membrane supporters. The most efficient separation was obtained using an acidic feed (pH at 1.8) with 1000 ppm gallium. Over a 12-h period of stripping, the striped Ga concentration increased with the HCl concentration from 0.5 to 2.0 M and then leveled off. The recovery rate in the pilot test exceeded that on the laboratory scale because the membrane area was greater. The pilot test yielded a high recovery percentage of gallium (at 91%) and a low recovery of arsenic (merely 1.3 ppm) in the strip over 72 h.
Tsai
Chin-Ying
CY
Department of Center for Environmental Safety and Health Technology, Industrial Technology Research Institute, Chutung, Hsinchu, Taiwan, ROC. LisaTsai@itri.org.tw
Chen
Yi-Fu
YF
Chen
Wen-Ching
WC
Yang
Fong-Ru
FR
Chen
Jyh-Herng
JH
Lin
Jing-Chie
JC
D001151:Arsenic / Q000302:isolation & purification*; D005708:Gallium / Q000302:isolation & purification*; D015386:Hazardous Substances; D007221:Industry; D008567:Membranes, Artificial; D011138:Polytetrafluoroethylene; D014873:Water Pollutants / Q000302:isolation & purification*; D018508:Water Purification / Q000379:methods*
D015386:Hazardous Substances; D008567:Membranes, Artificial; D014873:Water Pollutants; D011138:Polytetrafluoroethylene; D005708:Gallium; D001151:Arsenic