Stability evaluations of copper ethyl xanthate and copper butyl xanthate in an acid solution

In this study, two precipitates, copper ethyl xanthate (Cu-EtX) and copper n-butyl xanthate (Cu-BuX), were formed from two xanthate processes for metal [Cu(II)] removal from aqueous systems. The performances of both xanthate processes showed that they were capable of meeting effluent disposal standard of Taiwan. Stability characteristics of Cu-EtX and Cu-BuX in acid solutions were discussed using semi-dynamic leach test (SDLT), X-ray powder diffraction (XRD) measurements and UV-VIS spectroscopic methods. The results of SDLT after 60-day periods of 1N acetic acid (HAc) extractions points out that the cumulative leaching of copper was 0.82% and 0.004% of the total copper contained in Cu-EtX and Cu-BuX, respectively. The investigation of crystallinity showed as XRD patterns from Cu-EtX and Cu-BuX indicated that none of new peaks appeared during 60-day periods of extractions. Results of UV-VIS spectra showed that only few Cu-EtX decomposed to dixanthogen and carbon disulfide, and few Cu-BuX decomposed to carbon disulfide. Thus. it was assured that chemical stability of Cu-EtX and Cu-BuX in 1N HAc solution satisfied environmental requirements.