| An investigation on the occurrence of silver in the leach residue from a zinc plant has been carried out. Results obtained show that most of silver in residue occurs as sulfides which consist of metallic ions of copper, zinc, iron, silver etc, and sulfur ions. The composition of silver-bearing phase has been measured with the aid of SEM-EDAX, and the formation mechanism of silver-rich phase is discussed. It is revealed that a series of chemical change occurred in hy-drometallurgical process, and mineral's phases were changed completely. For example, argentite and silver-tetrahedrite in the original zinc concentrate have disappeared, and new minerals bearing silver formed in residue. They are Neo-covellite and Neo-silver sulfide complex phase. Silver is dispersed inside mineral bearing sil-vre. Some suggestions concerning controlling the process conditions for increasing the recovery of silver are given. This paper provides important photographs and data on silver occurrence forms. |