Flocculation-coagulation behaviour sudy of tailings of a fluorspar mineral processing plant

Abstract

The objective of this work is to carry out a selection study of the most adequate flocculationcoagulation reagents to reduce the solids content in the overflow from the settling lagoons of a fluorspar processing plant. This overflow has 1 % solids content, clarified from a feed of 25% solids in the settling lagoons, and is pilled into a river. The importance of this work is enhanced by the fact that the plant is located in a low water resources area, and that eventually the water from the river is used for agriculture or even human consumption. It is relevant to find a working methodology which allow to improve the efficiency of the clarifying process and minimize the environmental impact. Regarding the research methodology, a series of trials were made at natural pH and 25 °C to evaluate the action of those reagents which previously probed to be more efficient in this case: as flocculants were tried BOZEFLOC C 65, SEPARAN AP 273 P, SEPARAN MG 200, and as coagulant aluminium sulfate. The possible interaction of flocculation-coagulation processes was also studied, to obtain optimum result. As analysis critérium the total flocculation time was used, and as all essays were made in 100 ml probes, it corresponds with flocculation rate. As result of this study it can be concluded that the most efficient floculant was SEPARAN MG 200, at 4 g/T, with the observation that an excess of aluminium sulfate gets down the efficiency.