GROWTH OF COPPER SULPHIDE CRYSTAL IN GEL AND ITS THERMAL SPECTROSCOPIC SEMICONDUCTING CHARACTERISATIONS WITH KINETIC PARAMETERS

Copper sulphides crystals are grown using simple gel technique at ambient temperature. The various lattice parameters, gel aging time, gel setting time, Effect of pH observed, Different characterization like gel aging, pH of gel ,setting of gel with their analysis and Thermal behavior of grown crystal like Thermo gravimetric Analysis TGA are Discussed. The chemical analysis confirmed contents in grown crystal of copper sulphides

Temperature Controlled Evolution of Pure Phase Cu9S5 Nanoparticles by Solvothermal Process

Copper sulphides are one of the most explored semiconductor metal sulphides because of their stoichiometric and morphological dependent optical and electrical properties, which makes them tunable for numerous optoelectronic applications. Stoichiometrically, copper sulphides exist in numerous structures which varies from the copper-rich phase (Cu2S) to the copper-deficient phase (CuS). Within these extreme stoichiometric phases lies numerous non-stoichiometric phases with interesting optical properties. Different solvothermal techniques have been explored for the synthesis of copper sulphides; however, the thermal decomposition of single source precursors provides a facile and tunable route to the synthesis of pure phase copper sulphides of different stoichiometries. In this study, copper (II) dithiocarbamate have been explored as a single source precursor compound to study the evolution of pure phase Cu9S5. Below 240°C, mixed phase of CuS and Cu9S5 were obtained, and as the temperature was increased beyond 240°C, keeping other reaction condition unchanged, the precursor yielded pure phase of Cu9S5. This phase selectivity at high temperature was attributed to the increased reducing ability of oleylamine (used as solvent) which enhance the evolution of the copper rich phase at high temperature. Optical and morphological studies of the pure phase Cu9S5, showed properties that varied considerably with the temperature of synthesis.

Copper-Containing Agates of the Avacha Bay (Eastern Kamchatka, Russia)

The copper-containing agates of the Avacha Bay (Eastern Kamchatka, Russia) have been investigated in this study. Optical microscopy, scanning electron microscopy, electron microprobe analysis, X-ray powder diffraction, Raman spectroscopy, and fluid inclusions were used to investigate the samples. It was found that copper mineralization in agates is represented by native copper, copper sulphides (chalcocite, djurleite, digenite, anilite, yarrowite, rarely chalcopyrite) and cuprite. In addition to copper minerals, sphalerite and native silver were also found in the agates. Native copper is localized in a siliceous matrix in the form of inclusions usually less than 100 microns in size—rarely up to 1 mm—forming dendrites and crystals of a cubic system. Copper sulphides are found in the interstices of chalcedony often cementing the marginal parts of spherule aggregates of silica. In addition, they fill the micro veins, which occupy a cross-cutting position with respect to the concentric bands of chalcedony. The idiomorphic appearance of native copper crystals and clear boundaries with the silica matrix suggest their simultaneous crystallization. Copper sulphides, cuprite, and barite micro veins indicate a later deposition. Raman spectroscopy and X-ray powder diffraction results demonstrated that the Avacha Bay agates contained cristobalite in addition to quartz and moganite. The fluid inclusions study shows that the crystalline quartz in the center of the nodule in agates was formed with the participation of solutions containing a very low salt concentration (<0.3 wt.% NaCl equivalent) at the temperature range 110–50 °C and below. The main salt components were CaCl2 and NaCl, with a probable admixture of MgCl2. The copper mineralization in the agates of the Avacha Bay established in the volcanic strata can serve as a direct sign of their metallogenic specialization.

Copper-bottomed: electrochemically active bacteria exploit conductive sulphide networks for enhanced electrogeneity

Copper sulphides are shown to act as a conductive matrix improving the electrogenic performance of Geobacter dominated biofilms.

Modelaje Geoquímico de la Manifestación Volcanico-Exhalativa Submarina “Los Tramojos” en el Complejo Vulcanógeno Sedimentario de Cuba Central.

We studied an outcrop of massive iron-copper-zinc sulphides in Cretaceous volcanogenic intermediate to felsic rocks, located to the south of the village Los Tramojos, in the province of Sancti Spiritus, in Central Cuba. It is an artificial cut of dacitic tuffs and volcanic breccias with a strong mineralized area, dark in color, containing pyrite, magnetite, barite, sphalerite, bornite and others copper sulphides, as well as apatite, galenita and chalcopyrite. This area includes another tectonic zone with limonitic, hematitic, zeolitic and chloritic alterations, in contact with tuffs and non-mineralized and fresh volcanic breccias. It is a manifestation of a submarine volcanic-exhalative type. The mineralized area described above are very like the so call "Black Ores" of the Kuroko type of deposits. We investigated an area of 3,000 m2 using a soil grid of 25 x 10 meters, with some lithogeochemical samples. This study allowed to determine the correlation coefficients characteristic of the ore zone. We recommend the use of these correlation coefficients, combined with geophysical and perforation work, to check ore potential of the Sector "Los Tramojos".

Mineralization of the Zechstein Lower Anhydrite in the Fore-Sudetic Monocline

The paper presents the characteristics of ore mineralization of the Lower Anhydrite in the Fore-Sudetic Monocline. Both reduced and oxidized (Rote Fäule) rocks have been investigated. Reduced anhydrites are characterized by significant variability of metal concentrations and sulphide minerals. The most intensely mineralized anhydrites occur above the oxidized bottom part of the Lower Anhydrite. Mineralization in this part is dominated by copper sulphides (chalcocite, digenite, covellite, bornite and chalcopyrite) which are accompanied by galena and sphalerite. Further away from the oxidized zone, zinc and lead sulphides predominate over copper sulphides, and pyrite mineralization is also observed. Complex intergrowths and replacement textures of sulphides, as well as intergrowths of the ore minerals with sulphates and carbonates are considered to have formed after lithification of the enclosing sediments, and indicate that the original associations of sulphides were overprinted by superimposed later mineralization. Oxidized anhydrites generally have no significant concentrations of metals like Cu, Pb and Zn. The relict mineralization there is represented by remnants of tiny grains of copper sulphides (mainly covellite, digenite and chalcocite) and pyrite, profoundly altered as a result of their partial replacement by hematite. This mineralization present in the oxidized anhydrites indicates that hematite emplacement overlapped deposition of the original sulphides and extended oxidation up into the Lower Anhydrite. Position of the reduced and oxidized areas of anhydrites enriched in metals indicates centres of the most intense activity of the ascending mineralizing fluids.