The distributions of Ga, In, Sn, and Te between copper-iron mattes and silica-saturated iron silicate slags over a wide range of matte grades 55 to 75 pct Cu were determined at 1300 °C using a gas-phase equilibration-quenching technique and direct phase composition analysis by Electron Probe X-ray Microanalysis and Laser Ablation-Inductively Coupled Plasma-Mass Spectrometry. Alumina from aluminum, a typical minor element of electric and electronic copper scrap, and lime were adopted as slag modifiers for increasing the trace element recoveries. Gallium and tin were distributed predominantly in the slag, indium preferred sulfide matte at low matte grades and slag at high, whereas tellurium strongly favored the sulfide matte in particular in high matte grades. The slag modifiers alumina and lime had a minor impact on the distribution coefficients of gallium and tin, but for indium and tellurium the distribution coefficients were more strongly affected by the basic oxides. The strong tendencies of tin and tellurium to vaporize at the experimental temperature were confirmed.

Metal value recoveries in extraction are the key issue for sustainability of metals. The distributions of precious metals (Ag, Au, Pd, Pt, and Rh) between copper matte (a Cu-Fe-S-O melt) and silica-saturated iron silicate slag were determined at 1250-1350°C, under controlled oxygen and sulfur pressures and at fixed partial pressure of sulfur dioxide, in silica saturation for target matte grades of 55, 65, and 75 wt% Cu. High-temperature equilibration/ quenching was performed followed by electron probe X-ray microanalysis and laser ablation-inductively coupled plasma-mass sectrometry for measuring the major elements of the matte and slag, and trace elements of the slag, respectively. The distribution coefficient of silver at 65 % matte was found to be 150, which agrees well with the most recent studies in the literature. The other values obtained were gold 1500, palladium 3000, platinum 5000, and rhodium 7000-8000. The distribution coefficients increased along with matte grade, and for palladium it was approximately 1000 at 50 % Cu and 4000-5000 at 70 % Cu. The distribution coefficients decreased along with temperature but its impact was small. The distribution mechanism of the trace elements between iron silicate slag and copper matte appear to be dominated by properties of the matte phase.

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Potassic volcanics and intrusives of Eocene age (52±1 Ma) in the Highwood Mountains of north‐central Montana provide evidence for interaction of asthenospheric magmas with Archean mantle lithosphere of the Wyoming Craton. Diverse rock types were produced by shallow level degassing, fractional crystallization and magma mixing within two separate magma series whose parental liquids were latite and olivine minette. Halogen systematics of apatite microphenocrysts and other evidence have established that shallow degassing of the phlogopite‐diopside‐phyric minettes to yield heteromorphic leucite‐salite‐phyric mafic phonolites and shonkinites was an important process. Geochemical and mineralogical data suggest that fractional crystallization of olivine, clinopyroxene, mica and leucite, accompanied by widespread magma mixing, produced a spectrum of more evolved magmas such as leucite phonolites, malignites, alkali syenites and trachytes along with mica clinopyroxenite cumulates. Sr, Nd and Pb isotopic compositions and trace element data for the primitive olivine minette magmas are explicable by a multistage model involving three source components. One component is ancient Ba‐LREE‐enriched, U‐Th‐HFSE‐depleted subcontinental lithospheric mantle, which has been recognized in other alkalic rocks of the region, including those from the Crazy Mountains and Smoky Butte. Glimmerite‐veined harzburgite and phlogopite dunite xenoliths (one with ‐εNd of −33 at 52 Ma) found in the most primitive Highwood olivine minette are probably samples of this material. The other two components are asthenospheric mantle with isotopic composition near that of bulk earth (and dominant in Montana alnöitic diatremes) and a young subduction‐related component (probably Eocene, but possibly as old as late Cretaceous), which is required to explain the Rb/Sr‐87Sr/86Sr systematics of the Highwood rocks. A consistent model for the petrogenesis of the Highwood parental mafic magmas involves partial melting of asthenospheric mantle wedge triggered by infiltration of melts released from the metasomatized carapace above a low‐angle subducted slab of Farallon Plate lithosphere, followed by assimilative interaction of these melts with ancient, phlogopite‐rich, metasome veins upon ascent through the Wyoming Craton mantle keel.

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