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Effects of O 2 on aqueous SO 2 leaching of Co, Cu and Ni from discard smelter slag
Author(s) -
Ahmed Isaac B.,
Gbor Philip K.,
Jia Charles Q.
Publication year - 2002
Publication title -
the canadian journal of chemical engineering
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.404
H-Index - 67
eISSN - 1939-019X
pISSN - 0008-4034
DOI - 10.1002/cjce.5450800310
Subject(s) - leaching (pedology) , dissolution , chemistry , ferrous , smelting , metallurgy , aqueous solution , precipitation , slag (welding) , nuclear chemistry , inorganic chemistry , materials science , soil water , physics , meteorology , soil science , environmental science
In the leaching of non‐ferrous smelter slag with a dissolved gas mixture of SO 2 and O 2 , the behaviour of Co, Cu, Ni, Zn and Fe was studied in a 1‐L batch reactor. The parameters investigated include P SO2 , P O2 , temperature, particle size and pH. Co, Zn and Fe behaved similarly while Ni and Cu displayed distinguishable characters. The addition of O 2 prevented the precipitation of Cu after dissolution, and increased acidity of the leaching solution. The increase in acid strength resulted in an increase in the extraction of Co, Zn and Fe. The effect of acidity on Cu and Ni extraction was however much weaker. The combination of SO 2 and O 2 was found to be a more effective oxidant of Fe(II) to Fe(III) than O 2 alone. Simultaneous extraction of valuable metals and removal of Fe could be achieved by leaching at pH of 3 to 4. Maximum selectivities obtained for Co, Ni and Cu over Fe were 300, 2000 and 4000, respectively.