Selective precipitation of acid mine drainage for the obtaining of iron sulfate (III) applicable to water treatment

Abstract

The objective of the present investigation is to obtain iron sulphate (III) from the selective precipitation of the acid mine drainage to be used as a coagulant in wáter treatment. The possibility of selective precipitation is based on precipitation diagrams. It has been possible to obtain iron sulphate (III) by the selective precipitation of a synthetic sample of acid mine drainage, previously separating copper and zinc. The pH in a range of 3 to 4 and the concentration of sulfuric acid in the range of 30 to 40% are the significant variables unlike the moisture and solubility time of iron hydroxide(III) which are not significant according to with the Taguchi model. By batch sedimentation tests, using iron sulphate(III) as coagulant, the first stage of water treatment is considered by sedimentation of the bentonite -to 200 mesh- in 15 minutes is achieved.