A New Process Of Fluosilicic Acid Leaching For Recovering Bismuth From Materials Containing Bismuth Oxide

A new process of fluosilicic acid leaching for recovering bismuth from materials containing bismuth oxide is presented. The process includes two basic steps of purifycation by sulfuric acid leaching and recovering by fluosilicic acid leaching. First step, materials containing bismuth oxide is purified by the sulfuric acid leaching, which dissolves part of impurities such as copper oxide, iron oxide, manganese oxide to leach liquid. In this step, most of bismuth oxide is kept in the leaching residue, which increased bismuth oxide content in the solid material. Then residue from sulfuric acid leaching is leached by fluosilicic acid. In the step, bismuth oxide is dissolved into solution and formed the fluosilicic bismuth. The results show that the optimal condition is: concentration of fluosilicic acid 300g/L, leaching time 1 hour, leaching temperature 40 degrees C and liquid-solid ratio 5. The bismuth leaching rate obtained is above 98% under the optimal leaching condition.