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Compatibility of Nickel Electrolyte Containing Sodium Sulfate With a Solvent Extraction System.

Holmes-RA; Nilsen-DN; Siemens-RE
MISSING :12 pages
A Bureau of Mines method for recovering nickel, cobalt, and copper from low-grade domestic laterites is described, which includes the unit operations of solvent extraction and electrowinning. Previous Bureau work indicated that addition of na2so4 (sodium sulfate) to the nickel electrolyte improved current efficiency in nickel electrowinning. The present study determines the compatibility of na2so4 with nickel stripping in the solvent extraction operation of the Bureau method. The effect of adding 100 g/1 na2so4 on nickel stripping, phase disengagement, and ph was determined in comparative laboratory-scale tests. In continuous-circuit testing, na2so4 reduced stripping efficiency to the extent that five, instead of four, strip stages were required for complete stripping of nickel from the loaded solvent. In tests made in a phase-disengagement cell that had a variable settler area, the addition of na2so4 did not significantly affect phase separation characteristics. The ph of the nickel electrolyte in the temperature range of 20 deg to 65 deg c was also unaffected by the addition of na2so4. An economic evaluation showed that the energy saved by adding na2so4 to the electrolyte would more than offset the cost of adding another stripping stage.
Publication Date
Document Type
IH; Report of Investigations
Fiscal Year
Identifying No.
RI 8754
NIOSH Division
Source Name
Page last reviewed: September 2, 2020
Content source: National Institute for Occupational Safety and Health Education and Information Division