Synergism Among Collectors Used for Flotation of Apatite and REE Minerals

Conventionally within mineral processing, collectors are added as singular reagents or as mixtures to facilitate flotation. Therefore, in this article, a systematic change of collector type and addition order was carried out since the interactions between collector type, addition order and water quality have not previously been investigated. The tests were statistically planned in a way that the influence of the different collectors can be separated from their addition order. Two major series of flotation tests, one with tap water and one with process water were done. The results show that the presumably REE mineral selective hydroxamates do not work well with the apatite-iron ore tested. Instead, a sulfosuccinamate on its own, or in combination with oleate, gives good grade-recovery. The results clearly show that it is beneficial to first add a weaker/more selective reagent followed by a stronger collector. Comparing the runs with tap water vs. the ones with process water, oleate and hydroxamates are much more affected by the process water than the sulfosuccinamate. The reason is presumably that calcium and magnesium ions react/complex with these single-anionic reagents in solution, and thereby lower the amount that can adsorb to the mineral surface.