Determination of the concentrations of calcium and magnesium released from fluid inclusions of sphalerite and quartz

This study investigates the morphology of fluid inclusions trapped within a natural sphalerite and its closely intergrown quartz, and determines the total concentrations of calcium (Ca) and magnesium (Mg) released from the inclusions after grinding. The results indicated that numerous fluid inclusions with sizes from few microns to dozens of microns exist in the sphalerite and quartz. The inclusions contain abundant Ca and Mg. However, the concentrations of Ca and Mg in the inclusions of quartz are significantly lower than those of sphalerite. The inclusions were broken during the grinding process, releasing Ca and Mg to the solution; these released concentrations increased with the increase of grinding time. The maximum concentrations of Ca and Mg released from the fluid inclusions were 61.19 ppm and 5.23 ppm for sphalerite, and 3.28 ppm and 0.21 ppm for quartz, respectively. This study provides new understanding for the source of Ca and Mg in flotation pulp.