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The objects of the study were converter slags from the Balkhash copper plant in their initial state and after heat treatment. Using mineralogical and X-ray phase analysis, scanning electron microscopy (SEM), and electron probe microanalysis (EPMA), it was found that the initial converter slag and its thermally treated samples have identical matrices with almost complete coincidence in mineral and phase compositions. The distinguishing feature is the quantitative ratio of mineral components in the slag mass. Almost all of the iron is oxidized and present in the form of fayalite, magnetite, and magnetite, with other elements (silicon, copper, zinc, and aluminum) incorporated into its lattice. The structure of all slag samples indicates an association of sulfur exclusively with copper. Copper in the slags was identified in both metallic and sulfide forms. Slow cooling of the converter slag after its remelting contributes to the reduction in the sulfide–metal suspension in the volume of the melt and its coarsening. During slow cooling, structural changes occur not only in the main oxide part of the slag but also in the polymetallic globules. [ABSTRACT FROM AUTHOR]

The article describes the effect of the fluxing ability (FA) of ores used as a flux on slag formation and copper losses. In Kazakhstan, at the Balkhash copper smelting plant (BCSP), currently used fluxes have a very low SiO2 content—about 62%—whereas the Al2O3 content is 12%. Its fluxing ability (FA) was estimated, and it was shown that currently used silica fluxes have an exceedingly low FA. Only half of the fluxes participate in the slag formation. To obtain slags with a low magnetite concentration, a considerable surplus of flux must be added, which will result in a sharp reduction in its melt temperature, increased slag output, and therefore copper losses. The slag structure was studied by means of scanning electron microscopy and electron probe microanalysis (EPMA). To determine one of the primary causes of flux ores' low FA, it is necessary to use the microstructural pattern of experimental samples. [ABSTRACT FROM AUTHOR]