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An alternative method of acid leaching of silicon-containing metallurgical samples using ultrasonic vibrations is proposed in order to extract Si quantitatively from the solid phase into the solution. The effect of ultrasonic vibration, leaching temperature, phase contact time, weight of the sample, particle size, fraction of hydrofluoric acid in the reaction mixture was investigated. The results of laboratory studies showed that acid leaching assisted by ultrasonic vibrations is an efficient, safe and economically profitable way of sample preparation of silicon-containing metallurgical samples.

The paper describes the requirements for a student educational project, the stages of its implementation, the schedule. The use of project based technology in the educational process is considered in the preparation of students of chemical specialties within the framework of the discipline "Methods of mathematical processing of the results of chemical analysis." The use of the technology made it possible to form and develop a number of professional competencies related to improving the skills of sample preparation, measuring the analytical signal, statistical processing of the analysis results and the development of measurement techniques.

The results of the analysis of the reasons for the low academic performance of first-year students in Chemistry at a technical university are presented. Based on the monitoring results, an overview of pedagogical technologies used when teaching Chemistry is given.

Regularities of extraction of rhenium (VII) melt tetraoctyl-ammonium bromide in a mixture of higher alcohols and paraffin were determined. Quantitative extraction of measurements obtained in the range of pH of the aqueous phase 1.5–2.0 was carried out. It was shown that the degree of extraction of rhenium is reduced during the transition from sulfuric to nitric acid. The introduction of extracting 20% of higher alcohols improved the solubility of the extracted complex in paraffin. The composition of the complex, calculated, was 3.37±0.4.

Extraction concentration of rhenium by a melt of tetraoctylammonium bromide in paraffin was used with the aim of preparation of calibration samples for roentgen fluorescent analysis. The calibration characteristics of the roentgen fluorescent analysis of rhenium is established, its linearity is evaluated, a limit of detection and a limit of quantification (determination) of rhenium are calculated. The maximal value of the relative total standard uncertainty of the calibration characteristic does not exceed 1.45%. ristic does not exceed 1.45%.

The method including microwave acidic dissolution of samples and atomic-emission analysis of rhenium for determination of rhenium in cupper-molybdenum and lead-cupper wares is proposed. The range of determination concentration of metal is 0.05 – 0.5 mass percent, standard deviation of repeatability is 0.002 – 0.01 %.