Extraction of Cu and Pb from printed circuit board sludge using ammonia solutions.
Sludge from a printed circuit board factory containing high concentrations of Cu and Pb was characterized. Aqueous ammonia solutions were used to extract metals from the sludge. The extraction reactions were completed within 6 hrs. The best extraction efficiency was found at pH of 10.0. Higher solid-liquid ratio and higher ammonia concentration resulted in better extraction efficiency. Fractionation experiments showed that Cu and Pb were mainly extracted from the Fe-Mn oxide-bound and carbonate-bound fractions. Extracted sludge could meet the TCLP regulation limit and be categorized as a non-hazardous waste. Results show that ammonia extraction is of potential in resource recovery and in detoxification of hazardous waste.
Liu
J C
JC
Department of Chemical Engineering, National Taiwan University of Science and Technology, 43 Keelung Road, Section 4, Taipei 106, Chinese Taiwan.
Kao
T H
TH
D000641:Ammonia / Q000737:chemistry*; D003300:Copper / Q000737:chemistry / Q000302:isolation & purification*; D004581:Electronics; D006256:Hazardous Waste; D006863:Hydrogen-Ion Concentration; D007854:Lead / Q000737:chemistry / Q000302:isolation & purification*; D012037:Refuse Disposal / Q000379:methods*
D006256:Hazardous Waste; D007854:Lead; D000641:Ammonia; D003300:Copper