Microflotation and adsorption studies with an N-arylhydroxamic acid

A study was conducted to understand the adsorption of N-hydrocinnamoyl-N-phenylhydroxyl- amine (HCNPHA) on the surfaces of various pure minerals: sphalerite, pyrite, galena, chalcopyrite and quartz. HCNPHA is a member of the N-arylhydroxamic acids that are good base metal mineral collectors and HCNPHA gave the most promising results within the group.In this work, equilibrium studies were conducted at pH 9 and 10, using pure minerals and some microflotation studies were also undertaken. Chemisorption appears to be the most probable mechanism of adsorption on metal sulphide minerals. Microflotation studies were also conducted to understand the flotation of various minerals to HCNPHA at a pH range of 7 to 11. Optimum pH for sphalerite flotation was 9. Sphalerite was floated without the need for copper sulphate (CuSO4), which is very significant, as xanthates are unable to float sphalerite without CuSO4 (which is the costliest reagent). HCNPHA also required less CuSO4 than xanthates for reactivation of sphalerite.Xanthates are the collector of choice for mineral processing; therefore HCNPHA provides a promise in developing an environmentally friendly alternative for xanthates.