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Recovering Mercury from a Flotation Concentrate by Continuous Leaching-electrolysis.

Atkinson GB; Murphy JE; Eisele JA
MISSING :9 pages
The Bureau of Mines, in cooperation with McDermitt Mine, investigated a method for recovering mercury metal from mercury sulfide flotation concentrate by a hydrometallurgical technique. This preliminary report shows the feasibility of leaching mercury with a cupric chloride solution and electrowinning mercury from the solution. Proposed chemical reactions are shown in equations 1 through 3: 2cucl2 + hgs > 2cucl + hgcl2 + s deg.; (1) Electrolysis hgcl2 > hg + cl2; (2) 2cucl + cl2 > 2cucl2 (3) a bench-scale leaching-electrowinning apparatus capable of treating 2.36 Kg of sulfide concentrate in 11 days was operated continuously. An acid chloride solution containing, in grams per liter, 70 ca, 60 cu, 30 fe, and 80 hg was used as both leachant and electrolyte; 99.5 pct of the mercury was solubilized from the sulfide concentrate. Electrolysis of the leaching solution recovered mercury metal at an average current efficiency of 32 pct and an average energy consumption of 1.2 Kwhr/lb hg. Results from a preliminary economic evaluation indicated that a plant producing 31,500 flasks of mercury per year would have a capital cost of $3.7 million and an operating cost of $62 per flask of mercury.
Publication Date
Document Type
IH; Report of Investigations
Fiscal Year
Identifying No.
RI 8769
NIOSH Division
Source Name
Page last reviewed: November 12, 2021
Content source: National Institute for Occupational Safety and Health Education and Information Division