Hydrometallurgy of the delta sulfide ores, first stage report

This report presents the results of hydrometallurgical research carried out from September 16, 1985 to June 30, 1986 on metals recovery from complex sulfide ores from the Delta deposit near Tok, Alaska. The leaching characteristics performed for 6 different ore samples indicate that the most valuable components form the following order: Zn > Au > Pb > Ag > Cu > So. Further study demonstrates that direct leaching of the ore is effective both in chloride as well as in sulfate oxidizing solutions coupled with separating of leached solid components by flotation. Three variants of the ore processing with ferric chloride or fenic sulfate leaching are analyzed: one flowsheet with direct ore leaching in ferric chloride solution followed by leaching-flotation step, with subsequent zinc separation in a solvent extraction step and electrolysis in chloride solution; and two flowsheets of direct ore leaching with ferric sulfate solution followed by a leaching-flotation step, with zinc sulfate electrolysis and other metals recovery in chloride leaching sreps. In two last flowsheets silver is recovered during the chloride leaching steps and gold h m flotation products during the cyanide leaching. Preliminary economic and technical evaluation is presented. The engineering study on apparatus for the fast leaching- flotation processing and on better accumulation of gold and silver in one semi-product are concluded for the next year of research

Diabetes meds: some things old, some things new Les antidiabétiques : du vieux, du neuf

Diabetes meds: some things old, some things new Les antidiabétiques : du vieux, du neu

Low temperature annealing effects on the stability of Bi nanowires

To investigate the physical properties of Bi nanowires and to explore their possible implementation in thermoelectric devices, it is essential to understand their chemical and thermal stability in air both at room and moderate temperatures. In this work, we study the influence of low temperature annealing processes on the morphology and composition of the wires by scanning and transmission electron microscopy and by Raman spectroscopy, revealing the formation of a metal oxide phase. This oxidation process initiates an increase of the nanowires surface roughness at low annealing temperatures, while clear protuberances are formed at 250 °C. Difficulties to electrically contact single Bi nanowires, as well as the high resistance values measured and reported by other groups, are attributed to this oxidation process, which constitutes a clear challenge for the reliable characterization of Bi nanowires and the investigation of their performance