抄録
The present refining of copper from sulfide copper ores by pyrometallurgical process is lack for the environmental concerns, that is, generation of harmful SO2 gas and high energy consumption. Considering our environmental aspect and saving the energy, we directed our attention to recover Cu by using the more advantageous L-SX=EW (Leaching-Solvent Extraction-Electrowinning) method. This hydrometallurgical L-SX-EW method can be designed as a closed system and lessen the wastes from the process. Based on the investigation we have already reported with respect to the extraction mechanism of Cu2+ with EHO (2-ethylhexanal oxime), in this study the separation of Cu2+ was examined from the leached solution obtained after leaching copper sulfide ores with ferric chloride solution, and the realizability of the environmentally friendly hydrometallurgical process was also investigated. The extractant EHO is very effective to separate Cu2+ from the leached solution containing Fe2+, Fe3+ and Zn2+. Cupric ions are selectively extracted in the organic phase at chloride ion concentration, 3～5 mol/dm3, while Fe3+ and Zn2+ are not transferred into the organic phase. The stages and phase ratio (A/O) required to attain the desired Cu2+ recovery are estimated to be 2-stage countercurrent extraction with the phase ratio (A/O) of 1.5. In order to strip Cu with water from the organic phase, 6-stages countercurrent stripping with the phase ratio (O/A) of 1.8 are required. By the extraction and stripping operation, 10 g/dm3Cu2+ is purified and concentrated to 25 g/dm3 Cu2+.
