The effect of chemical reagents on flotation performance of a pentlandite ore: An attainable region approach

Chemical reagents are used in flotation processes to improve the recovery of minerals as well as facilitate the rejection of gangue material. In this article, we conduct laboratory scale flotation tests on a pentlandite ore obtained from Nkomati mine in South Africa. We then investigate the effects of a collector (sodium isobutyl xanthate)and a depressant (carboxymethyl cellulose)on the flotation efficiency of the ore. The attainable region (A.R)optimization technique is then applied in order to determine optimum dosages of the reagent mix that give result to maximum recovery of values. We elucidate that it is easier to understand the effect of individual reagents on an ideal flotation process. However, in real flotation systems, reagents are mixed and their interaction results in unpredictable synergistic effects on the process. Our analysis results of the flotation feed material reveal that optimum liberation of nickel occurs in the −38 + 24.7 μm size class. On the contrary, the deportment of gangue minerals such as magnesium and silicon shows that the least grades occur in the same size class. Our experimental results also show that the interactive effects of sodium isobutyl xanthate and carboxymethyl cellulose produce the highest nickel recovery at a collector dosage of 200 g/t and depressant dosage of 300 g/t. The same dosages also result in minimum recoveries of major gangue minerals in the ore, namely iron and magnesium oxide.