Chloride is one of the effective medium in which platinum group metals (PGMs) can be brought into a solution. Solvent extraction applied to refining process for PGMs offers several advantages over the traditional precipitation methods and distillation. Extraction and separation of Pt(IV) and Pd(II) from hydrochloric acid solutions was possible to extract Pt(IV) and suppress the extraction of Pd(II) using mixed extractants of APT 6500 (bis(2,4,4-trimethylpentyl)phosphinic acid), an acidic extractant and TBP (tri-n-butyl phosphate), a solvation extractant. However, the stripping of Pt(IV) loaded with mixed extractants of APT 6500 and TBP has not been investigated at all. In this study, the stripping of Pt(IV) loaded from hydrochloric acid solutions using mixed extractants of APT 6500 and TBP was investigated. As a result of the study, it was found that acids and ammonium chloride solutions were not effective for stripping of Pt(IV) loaded with mixed extractants of APT 6500 and TBP, but solutions of sodium sulfate, sodium nitrate, sodium perchlorate and sodium acetate were each effective. Also, it was found that the composition of APT 6500 and TBP concentrations, especially the TBP concentration, affected the stripping of Pt(IV).

High arsenic (As) content in copper ores and concentrates poses challenges to the smelting/converting process, particularly the environmental implications of arsenic emissions. As an alternative, high-pressure oxidative leaching (HPOL) of enargite ore was investigated in this study to achieve selective dissolution of copper and separation of arsenic from high arsenic-containing copper ore. The effects of leaching conditions such as the type of leaching medium, leaching temperature, and total pressure, were investigated. Ferric sulfate (Fe₂(SO₄)₃) was used as the leaching medium under optimized leaching conditions (160°C and 1.0 MPa total pressure). The results showed that the dissolution of copper from enargite ore was limited to around 65%, due to the agglomeration and passivation of mineral particles caused by elemental sulfur, as shown by SEM-EDS. However, the addition of NaCl as an additive significantly improved the copper dissolution rate to about 82%, while about 98% of arsenic was removed as scorodite (FeAsO₄•2H₂O).