Effects Of Variability In Grinding Environment On Pulp Chemistry And Surface Chemistry Of Cu-Zn Ore

This study focuses on the effect of grinding media on sphalerite surface chemistry and pulp chemistry.We monitored pH,ORP(Oxidation-Reduction Potential),conductivity and dissolved oxygen during grinding with a redesigned chamber.The experiment illustrates that when the grinding ore process continued,pH levels gradually increased while ORP and dissolved oxygen content rapidly decreased.The material and size of grinding media have a crucial impact on the pulp chemistry and the surface chemistry of Sphalerite.As for different size of balls,the study illustrates that a smaller diameter of spherical grinding medium will result in a greater consumption rate of the dissolved oxygen content,but lower ORP and pulp ions concentration.We studied the different aeration conditions and the experiment shows that an air-supported system will result in a greater consumption rate of the dissolved oxygen content,but lower ORP and pulp ions concentration with the air-supplied system.When we change the pyrite content of original ore and the study demonstrates that excessive pyrite will result in greater consumption rate of the dissolved oxygen content,but lower ORP and higher pulp ions concentration.Surface chemistry analysis by Time-of-Flight Secondary Ion Mass Spectrometry(TOF-SIMS)was performed on mill discharged sphalerite.It demonstrates that the formation of iron oxide and hydroxide species on sphalerite surface,as well as different types and different sizes of grinding medium could affect the mineral surface.Comparing the different grinding media,we find mild steel easier occurs electrochemical reacts with sulfide ore,leading to the formation of more iron oxide and hydroxide species because iron ions content increased.Compared with spherical grinding medium of 1 inch,medium of 0.5 inch could supply more iron ions for pulp and improve electricity reactions during grinding,thus leading to the formation of more iron oxide and hydroxide species on sphalerite surface.The iron oxide and hydroxide species will make the sphalerite surface more hydrophilic and lower absorption of copper ions(Cu2+),it reduces the recovery of Sphalerite.Air supported to closed system,prompting the electrochemical reaction toproceed positively due to the additional oxygen into the pulp,leading to the formation of more iron hydroxide surface and lower adsorption of copper ions.Excessive 10%pyrite added into grinding environment will lead to the formation of more iron hydroxide.From above,we could conclude that pulp and sphalerite surface chemistry are decided by the types and sizes of grinding medium,different aeration condition,as well as added excessively pyrite.Moreover,the electrochemical reactions in the grinding process and mineral surface reactions will affect the flotation behavior of sulfide ore.