Optimization of Electro Metal Electrowinning Nickel Metal Processing Resulted by Solvent Extraction Using Versatic 10 and Cyanex 272

Abstract

In general, nickel laterite are divided into two types, namely limonite and saprolite. Both are in different depths and have different percentage of nickel content. Saprolite ores have a high nickel content (1.5-3%), while limonite has a lower nickel content (below 1.5%) which causes the nickel refining process using pyrometallurgy (high-temperature melting) techniques is very expensive. Laterite ores from Southeast Sulawesi used in this study still contain a lot of impurities. In the previous research phase of solvent extraction, Versatic Acid 10 was chosen as a extractant to separate calcium and magnesium from the ore. This process produced a mix of nickel with cobalt. To separate nickel from cobalt, the selection of extractant Cyanex 272 was used, therefore nickel remains in its aqueous phase while cobalt is in the organic phase. Nickel in the aqueous phase is then purified by another recovery technique such as electrowinning Electro Metal Winning (EMEW) technology. This process is still not established for processing nickel from laterite ores. The observed process parameters in this research are time; voltage; flow rate; and boric acid concentration to get the optimum results in this EMEW process. The result shows that the optimum addition of boric acid is 1M with 1.39 mg nickel, the optimum voltage in this EMEW process is 4volts with 1.55mg nickel, the optimum time is two hours with the amounted of nickel metal is 1.67 mg, and the optimum flow rate is 1 liter/minute with 1.82 mg nickel.