Depressants in nanoemulsion systems applied to quartz and hematite microflotation

Nanoemulsion systems were investigated in the microflotation of quartz and hematite. Four different depressants were used: Maizena®, soluble starch, amidex, and amylose. The nanoemulsions comprise in a single stable phase varying amounts of water, kerosene, Flotigam EDA® (collector), and n-butyl alcohol, allowing all flotation reagents to be added at the same time, reducing interfacial tension and favoring their application in the process. Microflotation tests were performed in a modified Hallimond Tube and the zeta potential values of the minerals were determined in the presence and absence of reagents. Quartz floatability was not affected by depressants, even when concentrations of 100 ppm of depressant were used in the nanoemulsion. The determined isoelectric point of quartz (pH 2). High levels of hematite depression were obtained for all depressants (80%–90% depression). Quartz floatabilities of up to 95% were achieved by using nanoemulsions in the process.