The paper presents the results of industrial testing of an innovative technology for stabilizing refined ferrochrome slags based on targeted control of their chemical composition through regulation of the CaO/SiO₂ basicity ratio. The relevance of the study is associated with the problem of spontaneous slag disintegration during cooling caused by the formation of an unstable modification of dicalcium silicate, which limits the possibilities of further utilization and creates environmental and technological risks. Unlike conventional chemical stabilization methods based on the addition of boron-containing agents, the present work proposes a physicochemical stabilization approach implemented by off-furnace injection of expanded clay into the stream of molten slag through a tapping runner during discharge. This method enables rapid adjustment of the calcium-to-silicon oxide ratio directly at the stage of slag phase formation without interfering with the main smelting process. Experimental studies have shown that the addition of expanded clay reduces the basicity to a level below 1.4, which prevents the formation of thermodynamically and structurally unstable dicalcium silicate and promotes the formation of a stable silicate matrix. The resulting slag is characterized by high structural stability, the absence of spontaneous disintegration, and the preservation of a lumpy structure after cooling. Industrial trials confirmed the technological feasibility of the proposed solution, the absence of any negative impact on the metallurgical process, and the possibility of producing a marketable product suitable for application in the construction industry. The obtained results demonstrate the effectiveness of chemical composition control as a promising tool for stabilizing refined ferrochrome slags and provide a basis for the implementation of resource-saving and environmentally oriented technologies.

DOSZHANOV K.K.

Master technologist of workshop № 4, Aktobe ferroalloy plant, Aktobe, Kazakhstan.

E-mail: kuanyshdoszhanov84@gmail.com, https://orcid.org/0009-0001-3625-9423

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ferrochrome slag, stabilization, slag disintegration, basicity, expanded clay, dicalcium silicate, off-furnace treatment