Unconventional column flotation of low-grade gold fine particles from tailings

This work shows results obtained in the treatment of gold bearing tailings, using HIC, high intensity conditioning in combination with a modified “enriching” flotation cell named C3P, or three-product column. This cell has shown to yield, in all cases, clean, high grade concentrates because it separates selectively the froth rejected particles (drop-back or third product) and uses two washing water inputs. In a tailing sample, where gold was liberated, concentrate recoveries were of the order of 15% Au, with grades higher than 160 g t− 1 Au and enrichment ratio of the order of 120. With low gold grades (0.15–0.4 g t− 1 Au) and a poor liberation, this 3pc cell was able to produce a product (12% gold recovery) with the quality of a rougher flotation concentrate (13 g t− 1 Au). These results could not be attained in the conventional column cell operating under similar conditions. HIC, as a feed pre-treatment assisted the column flotation performance enhancing selectivity, recovery and process kinetics. Mass transfer and interfacial phenomena in columns and in HIC (gold–gold particle and gold–carrier particle interactions) were used to explain results obtained. Potential practical applications of this HIC-3PC-flotation scheme in the treatment of the valuable flotation tailings are discussed.