Wet Processing Silver-zinc Concentrates Technology

In this paper, a new hydrometallurgy process of Silver-zinc concentrate is researched. Silver-zinc concentrate comes from the flotation procedure of zinc leached residues.The process consists of : mixed acid leaching , leaching silver by thiosulfate method, extracting sulfur. In the first part, zinc is leached into solution, silver and sulfur is kept in the leached residue . At the next part, silver in the leached residue is separated from sulfurand recovered.The extracting sulfur procedure consists of: hot melt, screening, thermal filtering . At the fist step, sulfur got melted and enriched,then, it was extracted by filter.In the leaching process, some factors are investigated as follow, the concentration of acid (including sulfuric acid, nitric acid and hydrochloric acid ), the liquid-solid ratio, temperature and time.The experimental results show that the silver and zinc leaching rate is related to the factors: the quantity of sulfuric acid, nitric acid and hydrochloric acid;the ratio of liqiud-solid;temperature;reaction time, etc.Based on the possibility of industry application and the results of this experiment, on a 50g scale, a zinc leaching rate 99.99% and a silver leaching rate 98.84% are achieved in open system experiment under the following conditions: the ratio of sulfuric acid and water (volume ratio) : 3:1;the ratio of liquid-solid: 8:1, reaction temperature: 100℃;2 hours last, volume of adding hydrochloric acid: 10ml.At last, united experiment and recycle leaching are done to the test the process. In united experiment, a few results are achieved as follow: a 99.98% zinc leaching ratio and a 97.68% silver leaching ratio are achieved;and a 68% sulfur recovery ratio in the form of element of sulfur. Recycle leaching results show that the zinc sulphate was separate from the leaching solution.To process there are some specialties such as :(1) The leaching system of zinc and silver is simple.(2) The leaching ratio of zinc, silver, sulfur is high.(2) A new method of extracting sulfur is brought forward.(3) The process is a hydrometallurgy process.(4) The equipment used is normal.(5) The process do not destroy environment and is applied in industry easily.