Frothing Phenomena in Phosphate Gangue Flotation from Magnetite Fines with Fatty Acid based Collector and MIBC Frother

Dephosphorization of magnetite fines at LKAB is carried out by floating the phosphorous gangue using a fatty acid based collector namely Atrac and MIBC frother. Excessive and stable froth formation in flotation led to an unnecessary step of diluting the phosphate froth gangue component to transport to tailings damn. In this study the influence of reagents and their combinations on the froth production and stability was examined. Methods involved surface tension measurements, froth production and froth quality tests, zeta-potential and spectroscopy methods to resolve the possible collector and frother interactions. The froth production and quality was evaluated in the presence of apatite and magnetite solid particles as well. The volume and quality of froth produced by Atrac was found to be a function of concentration and pH, while MIBC formed non-stable froth with approximately the same volume independent of concentration. When Atrac is combined with MIBC the froth production and quality is enhanced. As no interaction was detected between the reagents, the increase of froth production is thought to be a change in electrostatic forces around the collector molecule by the frother. Atrac has a higher contribution to frothing than MIBC. Surface active partially hydrophobic apatite particles were observed to be the main factor causing extremely stable froth.