Contribution of fluid inclusions to variations in solution composition for sphalerite/quartz samples from the Yunnan Province, PRC

•Metal ions in the pulp phase have an adverse effect on flotation selectivity.•They can come from the fluid inclusions of minerals.•It was found that numerous fluid inclusions exist in natural sphalerite and quartz.•These fluid inclusions have abundant chemical components, such as metal ions.•And they can release their components to pulp during grinding process.

A large number of fluid inclusions with sizes from a few microns to hundreds of microns, containing both gas and liquid phases, have been found to exist in natural sphalerite and quartz. These inclusions are rich in Zn, Ca, Mg, Cl− and SO42−, due to the capture of diagenesis and mineralizing fluids during the ore-forming process. The inclusions are broken open during the grinding process and their contents released to solution, as confirmed by the abundant presence of various metal and non-metal components in the wash water and energy dispersive X-ray (EDX) spectroscopy results. At the same grinding fineness, i.e., a particle size around 85% less than 0.074 mm, the concentrations of Zn, Ca, Mg, Cl− and SO42− released from the fluid inclusions were, respectively, 8.79 × 10−6 mol/L, 1.52 × 10−3 mol/L, 2.11 × 10−4 mol/L, 10.99 × 10−6 mol/L and 20.94 × 10−6 mol/L for sphalerite, and 1.12 × 10−6 mol/L, 39.75 × 10−6 mol/L, 4.04 × 10−6 mol/L, 61.69 × 10−6 mol/L and 32.50 × 10−6 mol/L for quartz. The metal and non-metal components released from the fluid inclusions of sphalerite and quartz provides a new source of ions in flotation pulp.

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