Leaching behavior of metals from high-arsenic dust by NaOH-Na2S alkaline leaching
(1. School of Metallurgy and Environment, Central South University, Changsha 410083, China;
2. Cleaner Metallurgical Engineering Research Center, Nonferrous Metal Industry of China,
Central South University, Changsha 410083, China)
2. Cleaner Metallurgical Engineering Research Center, Nonferrous Metal Industry of China,
Central South University, Changsha 410083, China)
Abstract: Arsenic is selectively extracted from high-arsenic dust by NaOH-Na2S alkaline leaching process. In the leaching arsenic process, the effects of alkali-to-dust ratio, sodium sulfide addition, leaching temperature, leaching time and liquid-to-solid ratio on metals leaching efficiencies were investigated. The results show that the arsenic can be effectively separated from other metals under the optimum conditions of alkali/dust mass ratio of 0.5, sodium sulfide addition of 0.25 g/g, leaching temperature of 90 °C, leaching time of 2 h, and liquid-to-solid ratio of 5:1 (mL/g). Under these conditions, the average leaching efficiencies of arsenic, antimony, lead, tin and zinc are 92.75%, 11.68%, 0.31%, 29.75% and 36.85%, respectively. The NaOH-Na2S alkaline leaching process provides a simple and highly efficient way to remove arsenic from high-arsenic dust, leaving residue as a suitable lead resource.
Key words: high arsenic dust; alkaline leaching; leaching behavior; arsenic