Investigation towards controlled precipitation of nickel using H2S(g) by harnessing pH dependent sulphide speciation

Sulphide as a precipitating agent is effective as it facilitates the removal of heavy metals to very low residual concentrations (ppm - ppb levels) over a wide pH range, owing to the low solubilities (Ksp) of metal sulphides. However, previous work on metal sulphide precipitation has highlighted a number of challenges. The low solubilities of metal sulphides in combination with the rapid kinetics of sulphide precipitation leads to rapid, uncontrolled metal sulphide precipitate formation. The extremely high supersaturations result in high rates of nucleation, leading to the formation of particles with undesirable characteristics. In this thesis, to gain insight on the metal sulphide precipitation of nickel and cobalt from the RES, a simplified model system, consisting of a synthetic NiS04 solution with a concentration of 200ppm Ni2+, was utilised to determine the effect of H2S(g) as a precipitating agent.

Grantor dc:publisher.institution

Department of Chemical Engineering

Year dc:date.issued

2007

Author dc:creator

• Karbanee, Nazneen

Advisors dc:contributor.advisor

• Lewis, Alison Emslie
• Van Hille, Rob

Language dc:language.iso

eng

Handle dc:identifier.uri

http://hdl.handle.net/11427/5308

OAI identifier oai:identifier

oai:open.uct.ac.za:11427/5308