中国有色金属学报(英文版)
Transactions of Nonferrous Metals Society of China
Vol. 23 No. 9 September 2013 |
(1. Department of Mining Engineering, Mu?la Sitki Ko?man University, Mu?la 48170, Turkey;
2. Department of Metallurgical and Materials Engineering, Cumhuriyet University, Sivas 58140, Turkey;
3. Department of Mining Engineering, Cumhuriyet University, Sivas 58140, Turkey)
Abstract:Ovalbumin (OVA), chicken egg albumin, is an environmentally friendly, non-toxic, cheap surface active agent. It has electrochemically active sulfhydryl residues in molecular structure. OVA adsorption on pyrite as an alternative depressant was investigated by cyclic voltammetry, FTIR spectroscopy and flotation. Tests were conducted in a wide potential range in alkaline pH to clarify the role of electrochemical condition on the adsorption mechanisms and the rate of depression. In the absence of OVA, the floatability reached its maxima around slightly oxidizing condition. Beyond the range, it decreased presumably due to the formation of Fe-oxyhydroxides together with the hydrophilic S-containing species. OVA-pyrite interaction occurred in the whole examined potential range. Depressing effect of OVA increased gradually from reducing to slightly oxidizing potential, open circuit potential (OCP) of pyrite, mainly due to weak conformational changes in OVA molecules together with the hydrophobic interaction around OCP. The rate of depression reached its maxima at moderately oxidizing potentials, which was referred to electrostatic attraction. This level was almost kept at higher potentials owing to OVA adsorption as metal-chelates.
Key words: pyrite; froth flotation; ovalbumin; redox reactions; depression