Selective removal of As from arsenic-bearing dust rich in Pb and Sb
(1. School of Metallurgy and Environment, Central South University, Changsha 410083, China;
2. Cleaner Metallurgical Engineering Research Center, China Nonferrous Metals Industry Association, Changsha 410083, China)
2. Cleaner Metallurgical Engineering Research Center, China Nonferrous Metals Industry Association, Changsha 410083, China)
Abstract: The selective removal of arsenic from arsenic-bearing dust containing Pb and Sb in alkaline solution was studied. The influence of NaOH concentration, temperature, leaching time, liquid to solid ratio, and the presence of elemental sulfur on the dissolution of As, Sb and Pb in NaOH solution was investigated. The results indicate that the presence of elemental sulfur can effectively prevent leaching of lead and antimony from arsenic. The Sb2O3, As2O3 and Pb5(AsO4)3OH in the raw material convert to NaSb(OH)6 and PbS in the leaching residue, while arsenic is leached out as As(III) or As(V) ions in the leaching solution. Arsenic leaching efficiency of 99.84% can be achieved under the optimized conditions, while 97.82% of Sb and 99.97% of Pb remain in the leach residue with the arsenic concentration of less than 0.1%. A novel route is presented for the selective removal of arsenic and potential recycle of lead and antimony from the arsenic-bearing dust leached by NaOH solutions with the addition of elemental sulfur.
Key words: arsenic removal; sulfur; arsenic-bearing dust; alkaline leaching; lead; antimony