Concentration of Silver and Zinc from Pyrite Rich Complex Sulfide Ore by Flotation

Flotation methods of Tizapa ore, which is pyrite rich complex sulfide ore and occurs in the center of Mexico, have been investigated in order to concentrate silver and zinc. In the lead flotation for concentrating silver, the following three methods were tested: (1) the rougher flotation using ethyl aerofloat as a collector and Na2SO3 as a depressant for sphalerite and pyrite, followed by a 5 stage cleaning, (2) the same rougher flotation, and a single stage cleaning at an elevated temperature (60°C), and (3) the single stage hot flotation (60°C) without depressant. In all methods, lead concentrates were obtained with about 70% silver recovery. And then, zinc flotation tests were carried out using lead flotation tailings obtained by the above methods. In the zinc flotation, potassium dichromate was found to be the effective depressant for pyrite. The method (1) gave a poor zinc recovery. On the other hand, in the methods (2) and (3), zinc concentrates containing as high as 51% zinc were obtained with 56% and 69% zinc recovery, respectively.