STUDYING THE PHYSICAL­CHEMICAL PROPERTIES OF ALLOYED METALLURGICAL WASTE AS SECONDARY RESOURCE­SAVING RAW MATERIALS

Abstract

The properties of the phase composition and microstructure of slags from the alumothermic production of ligatures of refractory elements of various grades, as well as scale of the rapid cutting steel R6M5, were examined for the nature of the presence of alloying elements. This is required to ensure a decrease in the losses of Mo, W, as well as other alloying elements, through sublimation with an increase in the temperature when processing technogenic waste. Phase composition was determined by the method of an X-ray phase analysis. Microstructure was investigated at a scanning electron microscope in a combination with an X-ray microanalysis using the non-reference calculation method for fundamental parameters. It was determined that slags from the alumothermic production of ligatures АHМ-50 and АМVТ consist of CaAl4O7 and compounds AlV2O4 and CrO2. That could indicate a certain level of doping the alloy with the refractory elements. The phases of Al75Mo20W5 and Mo(Si, Al)3, which could be represented by metallic inclusions, were identified in the slag from the MFTA ligature smelting. The phases of scale of steel slag R6M5 are mostly represented by Fe3O4, Fe2O3 and FeO. In addition, FeWO4, MoO2, WC, Mo2C were found, which is explained by the elevated degree of W and Mo doping. It is not ruled out that a certain part of atoms in the alloying elements, including Cr and V, could exist in the form of replacement atoms in Fe oxides. The microstructure of the examined slags and scale was characterized by the disordered particles of different size and shape. The presence of particles with a relatively high content of alloying elements was detected in scale. Compounds with an elevated susceptibility to sublimation are absent in the studied materials. That leads to a relatively high degree of using the alloying elements and lowers certain restrictions for adding the examined slags to slag-forming mixtures and for temperature limits of melting modes. The use of slags from the alumothermic production, as well as scale of rapid cutting steels, in the charge for the smelting of a doping alloy ensured the extraction of refractory elements and an additional doping of the resulting product.