Research into adhesive ore-dressing technologies of fine- and nano gold

Purpose. To summarize domestic experience in creating technology for adhesive gold dressing and to describe key research results. Methods. Laboratory experimental and pilot research into the process of obtaining adhesively active coal and oil granules carrying particles of gold and adhesive extraction of nano-, thin- and fine gold from ore slurry, preparing carrying granules and their microscopy, spectroscopy of the water phase, designing an experiment to obtain a statistical model of adhesive abilities of coal and oil granules-carriers. Findings. Regime map of oil granulation process to produce coal granules carrying particles of gold was experimentally obtained. Rational regime parameters for pelleting granules have been determined: consumption of coupling reagent; granulometric composition of initial coal; slurry concentration; pelleting duration; slurry agitation intensity. It is recommended to use as original material coal with ash content Ad = 10%; particle size ?0.074 mm. Oil agent is oil of brand M100 and kerosene. The rational process schematics for adhesive gold dressing was developed, in particular, by cleaning flotation, which increases the extraction of Au up to 90% and allows to reach its environmental cleanliness nearly at the level of flotation. It is discovered for the first time that when the surface of coal oil granules is modified by crown ether, gold nanoparticles of the size 20 ? 30 nm concentrate on it, which can be explained by the formation of supramolecular ensemble “crown ether ? nano-gold”. The rational mode of pelleting has been substantiated and patented for the turbulence estimated by Reynolds number Re within 900 ? 12000. Theoretical foundations of the mechanism for producing coal and oil granules-carriers were developed, including its phenomenological scheme. Subprocesses lying behind adhesive “coal-oil” contact have been analyzed and the elementary act of aggregation and granules-carriers' formation has been investigated. The experiment was designed to obtain statistical models that describe the impact of various factors on stickability of “adhesive ? substrate” (“coal-oil granules ? gold”) combination. Originality. The scientific basis was laid and experimental testing was performed to prove feasibility of gold dressing adhesive technology. Rational regime schematics and process parameters of adhesive gold dressing were grounded, it was discovered that under the impact of crown ether nano-gold concentrates on the surface of granules-carriers. Practical implications. The results of laboratory and bench experimental studies can be used with sufficient accuracy to implement adhesive gold dressing of fine and nano-size particles within a “few hundred microns ? a few tens of nanometers”.