UBC Faculty Research and Publications

Hydrolysis of metallic ions in mineral processing circuits and its effect on flotation Laskowski, J. (Janusz), 1936-; Castro Flores, Sergio H.


Hydrolysis of metallic ions depends on pH and the products of hydrolysis either activate flotation, can lead to inadvertent activation of gangue particles, but can also depress flotation of valuable components. One of the most recently studied topics is the use of seawater in flotation. Seawater is a concentrated NaCl solution (about 0,6 mole/L) that also contains considerable amount of Mg²⁺ and Ca²⁺ ions. The hydrolysis products of Mg²⁺ strongly depress flotation of molybdenite over the pH ranges over which they form in the process water. This effect can be eliminated by removal of hydrolysing ions from the process water or by carrying out the flotation at the pH over which such a hydrolysis can be avoided. The former can be exemplified by prior precipitation of the harmful hydrolysing ions as, for example, in the University of Concepcion Patent. The latter can be exemplified by the use of metabisulfite to depress pyrite in the flotation of Cu-Mo sulfide ores in seawater, the process that is carried out at much lower pH which avoids formation of Mg²⁺ hydrolysis products.

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