Voropayev V. Optimization of the fair assay smelting stage at the determination of noble metals in ores and refining products.

The objects are fire assay smeltting as the stage of noble metals' extraction in diferent alloys. Purpos: development (formation) of effective fire assay atomic absorption techniqes of noble metals' determination in geologi and metallurgy objects with adding of low frequency on the stage of sample preparation and removal of determinated elements' losses during the process of burning and fire assay smelting. Меthods:fire assay, gravimetric analysis, atom-absorption and X-ray fluoresctnt spectroscopy, metallography, micro-X-ray sprctrum analysis. Results: ultrasonic use for intensification of noble metals' fire assay extraction processes on lead, tin, copper, copper-nickel and nickel-sulfide header. It allows to decreas the process temperature on 50-100 °С and smelting time in 3-4 times noble metals' losses become lower them 1-2 %. It was found that ultrasonic influence allows to smelt the sample of different nature with 98-99 % extraction of determined elements in wide range of bed components ratio in difference of standart techniques where bed composition is calculated individualy for each tipe of samples. The noble metals' distribution in lead alloy received by the ultrasonic action was estab lished. The depandance of noble metals' extraction degree on silicium dioxid in bed was found. Ultrasonic was used for intensification of burning stage of sulfur-containing stuff. It was shown that the burning time of sulfur-containing sample decreases in 6-8 times. Volume of providing: introduce on chemical faculties DNU, in Analytical-Technical Investigation Center of Mining National University, in analytical laboratory of state enterprise "Dnepr-VDM". Region of utilization - analytical chemistry.