Activation of high-iron marmatite in froth flotation by ammoniacal copper(II) solution

Froth flotation of high-iron marmatite particles activated by ammoniacal copper(II) solution has been studied in this work. This study was performed on single marmatite mineral of 76–125 μm in size and 20% iron content by using micro-flotation. The results have shown that ammoniacal copper(II) solution effectively activated high-iron marmatite particles in the flotation with xanthate as the collector, being much better than copper sulfate, a traditional activator for sphalerite and marmatite flotation. Also, the maximum activation by ammoniacal copper(II) solution in the flotation appeared around pH 9, compared with pH 13–14 by copper sulfate. Therefore, the substitution of ammoniacal copper(II) solution for copper sulfate in high-iron marmatite flotation would increase the separation efficiency and would allow large savings on the consumptions of lime and xanthate. Based on the species distribution diagram for copper(II)–ammonia system, it has been found that the activation of ammoniacal copper(II) solution in high-iron marmatite flotation might be originated from copper(II)–ammonia complexes, CuNH32+ and Cu(NH3)22+, through the adsorption on the mineral surface.