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The work presents the results of studying ash and slag disposal areas of Primorsky Krai energy enterprises-the objects with high concentrations of Au and Ag. The chemical and mineral contents of samples from the investigated ash and slag disposal areas have been determined. It is shown that the found particles of free gold and of other noble metals are mostly represented by fi ne and ultrafi ne sizes. It is also shown that morphology diversity is typical of gold microparticles. The patt erns of Au collection and allocation during the working process in ash and slag waste (ASW) were found. The possibility of using the materials obtained during the separation of ASW as materials for diff erent industries is shown. An appropriate, multistage way of complex ASW recycling has been developed. The possibility of creating a profi table plant for complex processing of ASW is shown. It is also shown that additional extraction of useful components from concentrates of gold and platinum group metals (PGM) can signifi cantly reduce the payback period of production on complex processing of ASW. KEY WORDS: technogenic deposits of gold, wastes of energy enterprises, ash and slag, complex recycling of mineral raw materials, fi ne-dispersed gold, iron-bearing concentrate, coal underburning

This paper deals with the production and the mechanical testing of natural fibre‐based hybrid composites. Hybrid composite is produced by vacuum assisted resin infusion method of woven jute fabric and nonwoven wool felt along with glass fabric. Tensile, flexure and impact properties have been evaluated and compared. The tensile strength and the Young's modulus were found to be 70.66 MPa and is 5.63 GPa, respectively. Flexure and impact tests were performed on both woven jute fabric surface and on nonwoven wool felt surface of the composite specimens. The highest flexural strength was obtained in the specimen loaded at the woven jute fabric surface. Impact test results show that the specimens impacted at the nonwoven wool felt surface were carrying higher loads than the specimens impacted at the woven jute fabric surface.

This paper presents the results of the study dedicated to the determination of the optimum parameters for the electrolytic gold precipitation from thiourea leach solutions. The leaching was carried out using technogenic gold-bearing raw materials (gold-bearing sands) of the Far East of the Russian Federation. The study focused on the influence of the below parameters of electrolytic precipitation: electrolyte composition, overall cathodic current density, electrode voltage, and structural design of an electrolytic cell. As the results of the experiments, the optimum electrolyte composition and parameters of the current (overall cathodic current density 1000 А/m 2 , electrode voltage 6 V) were determined. Under these parameters, it is possible to recover up to 93 % of gold from thiourea leach solutions.