Search

Sb- and Bi-rich copper anodes, anode slimes and decopperised anode slimes from industrial copper electrorefineries were studied mineralogically. Sb in the anodes occurs mainly as Cu-Pb-As-Sb-Bi oxide inclusions along the copper grain boundaries; Bi is mainly present as Cu- Pb-As-Sb-Bi oxide, Cu-Bi-As oxide, Cu-Pb-As-Bi oxide and Cu-Bi oxide inclusions. Sb and Bi partly dissolve during electrorefining, but extensively reprecipitate as As-Sb oxide, As-Sb-Bi oxide and SbAsO4. The presence of As results in the precipitation of essentially all the Bi as BiAsO4. The decopperising process dissolves much of the Sb and Bi, although the majority of the BiAsO4 phase remains unaffected. Subsequently, some of the dissolved Sb and Bi reprecipitates as various oxide, sulphate and arsenate species. X-ray absorption near-edge structure (XANES) analysis suggests about 70% of the Sb in the anode slimes is present in the pentavalent oxidation state, whereas most of the Bi in all the slimes samples is in the trivalent oxidation state., Sb- and Bi-rich copper anodes, anode slimes and decopperised anode slimes from industrial copper electrorefineries were studied mineralogically. Sb in the anodes occurs mainly as Cu-Pb-As-Sb-Bi oxide inclusions along the copper grain boundaries; Bi is mainly present as Cu- Pb-As-Sb-Bi oxide, Cu-Bi-As oxide, Cu-Pb-As-Bi oxide and Cu-Bi oxide inclusions. Sb and Bi partly dissolve during electrorefining, but extensively reprecipitate as As-Sb oxide, As-Sb-Bi oxide and SbAsO4. The presence of As results in the precipitation of essentially all the Bi as BiAsO4. The decopperising process dissolves much of the Sb and Bi, although the majority of the BiAsO4 phase remains unaffected. Subsequently, some of the dissolved Sb and Bi reprecipitates as various oxide, sulphate and arsenate species. X-ray absorption near-edge structure (XANES) analysis suggests about 70% of the Sb in the anode slimes is present in the pentavalent oxidation state, whereas most of the Bi in all the slimes samples is in the trivalent oxidation state.

Bi- and Sb-rich copper anodes, anode slimes and leached (decopperised) anode slimes from two commercial copper refineries were studied mineralogically in order to determine the behaviour of these elements during copper electrorefining. Bismuth in the Bi-rich copper anode was present mainly as Cu-Pb-As-Sb-Bi oxide, Cu-Bi-As oxide, Cu-Pb-As-Bi oxide and Cu-Bi oxide inclusions, occurring along the copper grain-boundaries, while antimony in the Sb-rich copper anode occurred mainly as Cu-Pb-As-Sb-Bi oxide inclusions. A minor fraction of the Bi and perhaps 20% of the Sb was likely to be present in solid solution in the copper crystals. X-ray absorption near-edge structure (XANES) analysis indicated that the majority of the bismuth in the Bi-rich copper anode, anode slimes and leached slimes was present in the trivalent oxidation state. Preliminary XANES analysis demonstrated that about 70% of the antimony in the anode slimes and the leached anode slimes was present in the pentavalent oxidation state and about 30% occurred in the trivalent oxidation sate. The dominant antimony species in the copper refining electrolyte, however, appeared to be trivalent., Bi- and Sb-rich copper anodes, anode slimes and leached (decopperised) anode slimes from two commercial copper refineries were studied mineralogically in order to determine the behaviour of these elements during copper electrorefining. Bismuth in the Bi-rich copper anode was present mainly as Cu-Pb-As-Sb-Bi oxide, Cu-Bi-As oxide, Cu-Pb-As-Bi oxide and Cu-Bi oxide inclusions, occurring along the copper grain-boundaries, while antimony in the Sb-rich copper anode occurred mainly as Cu-Pb-As-Sb-Bi oxide inclusions. A minor fraction of the Bi and perhaps 20% of the Sb was likely to be present in solid solution in the copper crystals. X-ray absorption near-edge structure (XANES) analysis indicated that the majority of the bismuth in the Bi-rich copper anode, anode slimes and leached slimes was present in the trivalent oxidation state. Preliminary XANES analysis demonstrated that about 70% of the antimony in the anode slimes and the leached anode slimes was present in the pentavalent oxidation state and about 30% occurred in the trivalent oxidation sate. The dominant antimony species in the copper refining electrolyte, however, appeared to be trivalent.

Gold in copper anodes occurs in solid solution in the copper crystals. During electrorefining, the copper dissolves and the associated gold is released. Most of the gold reports as tiny metallic Au particles in the anode slimes and some of the metallic gold appears to nucleate on the selenide inclusions that are liberated during electrorefining. Gold is also detected both in solid solution in the liberated selenide particles and as discrete Ag-Au-Cu selenide phases. In anode slimes containing low to moderate Ag and Se contents, the majority of the gold occurs in metallic form. A significant fraction of the gold in high-Se and high-Ag anode slimes is present in the selenide phases. The formation of Au-bearing selenide species implies the limited solubility of gold in copper sulphate electrolytes. The decoppering of anode slimes containing moderate concentrations of Ag and Se at temperatures below 100 degrees C and atmospheric pressure generates mostly metallic gold, together with minor amounts of Au-bearing selenide species. A greater fraction of the gold is converted to selenide species when high-Se and high-Ag anode slimes are decopperised at elevated temperatures and pressures. Although the relative amounts of the gold species in the decopperised products generated under moderate temperature and atmospheric pressure conditions are not totally identical to those generated by decoppering high-Ag and high-Se anode slimes at elevated temperatures and oxygen pressures, the behaviour of gold during decoppering is the same. Gold shows a strong affinity for Ag and Se during the process. The mineralogical observations were confirmed by Mossbauer spectroscopy and X-ray near-edge structure analysis and the applicability of the two techniques for Cu refinery products is compared., Gold in copper anodes occurs in solid solution in the copper crystals. During electrorefining, the copper dissolves and the associated gold is released. Most of the gold reports as tiny metallic Au particles in the anode slimes and some of the metallic gold appears to nucleate on the selenide inclusions that are liberated during electrorefining. Gold is also detected both in solid solution in the liberated selenide particles and as discrete Ag-Au-Cu selenide phases. In anode slimes containing low to moderate Ag and Se contents, the majority of the gold occurs in metallic form. A significant fraction of the gold in high-Se and high-Ag anode slimes is present in the selenide phases. The formation of Au-bearing selenide species implies the limited solubility of gold in copper sulphate electrolytes. The decoppering of anode slimes containing moderate concentrations of Ag and Se at temperatures below 100 degrees C and atmospheric pressure generates mostly metallic gold, together with minor amounts of Au-bearing selenide species. A greater fraction of the gold is converted to selenide species when high-Se and high-Ag anode slimes are decopperised at elevated temperatures and pressures. Although the relative amounts of the gold species in the decopperised products generated under moderate temperature and atmospheric pressure conditions are not totally identical to those generated by decoppering high-Ag and high-Se anode slimes at elevated temperatures and oxygen pressures, the behaviour of gold during decoppering is the same. Gold shows a strong affinity for Ag and Se during the process. The mineralogical observations were confirmed by Mossbauer spectroscopy and X-ray near-edge structure analysis and the applicability of the two techniques for Cu refinery products is compared.

In the energy spectrum of an occlusion sequence, the distortion term has the same orientation as the velocity of the occluding signal. Recent works claimed that this oriented structure can be used to distinguish the occluding velocity from the occluded one. Here, we argue that the orientation structure of the distortion cannot always work as a reliable feature due to the rapidly decreasing energy contribution. This already weak orientation structure is further blurred by a superposition of distinct distortion components. We also indicate that the superposition principle of Shizawa and Mase for multiple motion estimation needs to be adjusted.