Impact of serpentine particle coating on the adsorption of ethyl xanthate on pentlandite surface in flotation

Serpentine, a prevalent magnesium - bearing silicate mineral found in nickel ore, significantly depresses the flotation of valuable sulfide minerals by covering their surfaces. However, the impact of the serpentine coating on the adsorption of xanthate on the pentlandite surface remains unclear. Flotation and adsorption experiments demonstrated that serpentine has a significant depressing effect on pentlandite flotation, but has no noticeable influence on the adsorption of ethyl xanthate (EX). Electrochemical tests, including open circuit potential, cyclic voltammetry, and chronoamperometry, revealed that even when serpentine covers approximately 76.8 % of the pentlandite surface, the adsorption amount of EX shows negligible changes, and the diffusion coefficient of EX (approximately 3 x 10-6 cm2/s) on the pentlandite surface remains unchanged. Calculations show that the contact area between serpentine and pentlandite constitutes only 0.15 % of the pentlandite surface area, with virtually no decrease in the positions where EX can be adsorbed. This study provides novel insights into the impact of macroscopic mineral particle interactions on the microscale adsorption of collectors in the flotation process.