I.N. Tanutrov, S.A. Lyamkin, M.N. Sviridova.
ABSTRACT
Pyrometallurgical technology for obtaining germanium concentrates from raw materials brown coal deposits (coal, mudstones, siltstones) are accompanied by the production of melts of silicate slags. Mineral water is concentrated in the slags a component of raw materials that reaches 60% by weight. It is obvious that technological indicators of processes are largely determined by the physical and chemical properties of slag melts. These include density (ρ) and surface tension (σ), reflecting the structure of silicate melts. The composition of slags from the processing of carbonaceous raw materials is significantly different from the slags of non-ferrous and ferrous metallurgy: they contain increased amounts of SiO2 (up to 50–55%), Al2O3 (up to 20–22%), and K2O and Na2O (up to 5–6%). In addition, significant amounts of sulfide sulfur (up to 3%) and trace amounts of non-ferrous metals and rare elements (up to 5%) are present in the slags. Differences in the composition of slag melts of germanium production from the slags of the main metallurgy are reflected in their properties and require special research. The objects were industrial samples of cyclone melting and electric melting slags. We applied the method of semi-synthetic samples obtained from industrial samples by adding SiO2 and CaO to determine the effect of the composition on the ρ and σ. For measurements, the method of maximum pressure in an inert gas bubble blown in the melt was used, more precisely, a differential variant that allows increasing accuracy.
The cell was a melt under study in an alumina crucible with an alumina capillary immersed in it and a comparison capillary submerged in distilled water. The range of temperature measurements in the melt was in the range of 1100–1400°C. As a result of measurements, it was found that the values of ρ and σ of melts are in the range from 2.20 to 4.30 t/m3 and from 218 to 531 mN/m, respectively. The values of ρ and σ depend significantly on basicity (the ratio of the sum of CaO and MgO contents to SiO2), as well as the content of Al2O3. It is found that the temperature dependences p and σ have a linear character with negative temperature coefficients. In general, the studied melts differ markedly, for example, from the slags of the blast furnace at equal basicity. The research results are useful for predicting the structure of melts and their behavior in real conditions .
KEY WORDS:
germanium concentrate, pyrometallurgy, melt, density and surface tension.
DOI: 10.31857/S0235010620060134