- Title
- Electrochemical studies of organic compounds in zinc electrowinning circuits
- Creator
- Vawdrey, Peter
- Date
- 1986
- Type
- Text; Thesis; Masters
- Identifier
- http://researchonline.federation.edu.au/vital/access/HandleResolver/1959.17/57847
- Identifier
- vital:4166
- Abstract
- Most of Australia's zinc production is by the electrolytic zinc process, in which zinc is electrowon from an acid sulphate solution. The process is known to be exceptionally sensitive to the presence of trace impurities. At the Electrolytic Zinc plant (Risdon, Tasmania), isobenzofuranone (pthalide) has been detected in the electrowinning circuit, and found in higher concentrations during efficiency slumps. It was found that di-2-ethylhexyphthalate, (present in the liners and plastics used in the electrowinning circuit), is reduced to isobenzofuranone under the electrolysis conditions employed. In addition, an investigation involved a constant current electrolysis of a synthetic zinc electrolyte, as identified an additional pathway for the productionof isobenzofuranone. 2-Naphthol, added to the electrolysis circuit for current efficiency purposes, is also a major precursor of isobenzofuranone. 2-Napthol and possibly 1-nitroso-2-napthol can be oxidized to pthalic acid, either at a lead anode or via anode oxidation productions, and the phthalic acid produced can be reduced to isobenzofuranone at a zinc cathode. In addition, it was found that isobenzofurane is further reduced at the potential of zinc deposition to ultimately yield 2-methylbenzaldehyde. This compound, which has also been detected in Risdon plant electrolytes, is also toxic in the zince electrowinning circuit. The compound 2-methylabenzyl alcohol has also been detected via GLC examination of Risdon plant liquors. However, this compound was not detected in the present investigation, and thus no explanation can be offered for its presence in plant electrolytes. The toxicity of zinc electrolyte impurities on current efficiency was determined by a cyclic voltammetric technique. The results of this investigation indicate that the presence of isobenzofuranone and 2-methylbenzaldehyde can significantly lower current effciency, and the compounds phthalic acid and 2-methylbenzyl alcohol also lower efficiency.; Masters Degree in Applied Science
- Publisher
- The author [Mt. Helen, Vic.] :
- Rights
- Open Access
- Rights
- This metadata is freely available under a CCO license
- Subject
- Zinc; Metallurgy; Zinc industry and trade
- Full Text
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