Research on the Selective Grinding of Zn and Sn in Cassiterite Polymetallic Sulfide Ore

Abstract

When cassiterite polymetallic sulfide ore is being ground in the ball mill, the contradiction between over grinding of cassiterite and under grinding of sulfide ore is inevitable due to their mechanical property differences. In this paper, a selective grinding characterization method is proposed to optimize the grinding of cassiterite polymetallic sulfide ore based on the respective selective grinding indexes, namely, the changes in the cumulative grade and cumulative quantities of metal. The preferred grinding characteristics were studied by varying three grinding operation factors, the grinding time, grinding concentration, and mill speed, as these all affect the selective grinding behavior of the ball mill. In the proposed method, the breaking process preferentially begins with the Zn minerals in the cassiterite polymetallic sulfide ore; however, Sn minerals are found to break first when the specific energy of the grinding media is large. The differences in the crushing characteristics of Zn and Sn minerals narrow down as the grinding time and concentration increase. When the grinding concentration is lower than 50%, the two types of minerals are broken with little difference. However, when the grinding concentration is higher than 50%, the Zn minerals are broken prior to the Sn minerals.