The Bureau of Mines is evaluating a method for selectively extracting nickel and cobalt from low-grade domestic laterites. Preliminary laboratory-scale electrowinning tests were conducted in both a nondiaphragm and a diaphragm cell to determine the effect of variables on energy efficiency under controlled conditions. Electrolytes were prepared to stimulate electrolyte that could be obtained by stripping nickel- and cobalt-rich solvent extraction reagents. Limited tests were conducted with electrolyte generated from laterite leach solutions. Electrical energy consumption in a nondiaphragm cell was 2.06 Kwhr/lb ni with the cell operated at 50 deg c, a cell feed of 90 g/l ni, a ph of 3.5, An extraction of 3.2 G/l, and a cathode current density of 20 amp/ft2. The energy requirement decreased with increasing concentration and temperature, and increased with increasing extraction and current density. At 50 deg c, energy consumption in the nondiaphragm cell was 21 pct greater than in the diaphragm cell, but it was only 5 pct greater at 65 deg c. For this reason and because of overall cost considerations, operation at 65 deg c with the nondiaphragm cell was preferred. Smooth sheets of cobalt were obtained by electrowinning in a nondiaphragm cell at selected temperatures from 50 deg to 85 deg c and with cobalt concentrations from 55 to 87 g/l. The energy consumption (1.48 Kwhr/lb) was 22 pct lower with a cobalt concentration of 75 g/l and a cell temperature of 65 deg c than with a cobalt concentration of 55 g/l and a cell temperature of 50 deg c.