On the fundamental aspects of apatite and quartz flotation using a Gram positive strain as a bioreagent

Mineral bioflotation encompasses the principles and methods used in mineral flotation using microorganisms as flotation reagents. This work deals with the fundamental aspects of apatite and quartz flotation using Rhodococcus opacus bacteria as a bioreagent. Each mineral sample was conditioning with the bacterial suspension in a rotary shaker under specific conditions as particle size, biomass concentration, pH solution and conditioning time, for all the studies done during the research. The zeta potential results showed a change in zeta potential measurements of the minerals after the bacterial interaction. This change was more significant in the zeta potential curves of apatite than those for quartz. The results also suggest that the bacterial adhesion onto the mineral surfaces was predominantly specific. The greatest apatite flotability achieved 90% at pH around 5, in the presence of 150 mg L−1 of bacteria after 5 min of flotation. On the other hand, quartz achieved a flotability of 14% under identical experimental conditions. The fundamental flotation studies revealed the prospect that R. opacus presents as a biocollector and biofrother and indicate its promising application in phosphate flotation industry.

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► Environmental bioreagent for mineral flotation.
► Rhodococcus opacus bacteria affect the mineral electrophoretic behavior.
► The flotability of apatite and quartz depends on the pH value.
► R. opacus bacteria act as a biocollector and a biofrother.
► R. opacus presents a relevant potential as a bioreagent for mineral processing.