EFFECT OF CORROSION-INHIBITORS ON GRINDING AND FLOTATION OF A LEAD-ZINC ORE

Grinding and flotation experiments on a Pb-Zn ore were carried out to evaluate : 1) wear of the grinding media both in the presence and abse nce of an inhibitor and 2) effect of the inhibitor on the flotation of Pb-Zn minerals. The percentage reduction in the wear of the grinding media was observed to be between 25-36%, depending on the type of the inhibitor and its critical concentration. The inhibitors used in the i nvestigation were sodium sulphite, sodium nitrite, sodium chromate and sodium silicate. The results indicate that a specific corrosion inhib itor, for example sodium sulphite, may give better recoveries and grad es in flotation but is not as efficient as sodium chromate in inhibiti ng the wear of the grinding media. Pulp solutions (after grinding) ana lysed for metal ion concentrations showed low Fe. Iron released into t he solution as a result of corrosion reactions subsequently forms inso luble hydroxy complexes and may coat the mineral surfaces. Such hydrop hilic coatings may adversely affect the floatabilities of minerals. Th e particle size analysis of the ground product has been carried out an d the results are discussed.