Behavior of silver and lead in selective chlorination leaching process of gold-antimony alloy
(School of Metallurgical Science and Engineering, Central South University, Changsha 410083, China)
Abstract: The behavior of silver and lead in the selective chlorination leaching process of gold-antimony alloy was analyzed in detail and appropriate recovery methods were developed. A reduction method by adding gold-antimony alloy powder was adopted to recover silver according to the thermodynamics calculation. The reducing rate of silver can exceed 99% at 80 ℃ for 1.5 h when the dosage of gold-antimony alloy powder is 10%. The dissolution equilibrium curved surfaces of PbSO4 and PbCl2 under different conditions were drawn. The experimental results are well consistent with theoretical analysis that indicate lead may be precipitated in the form of lead chloride. The grade of gold in the residue can be further concentrated to 94.5% after being washed with hot water. These two methods have been applied successfully in the practice.
Key words: silver chloride; lead chloride; gold-antimony alloy; chlorination leaching