Stabilization of Self-slaking Slags from Ferroalloy Production
Abstract
In this study, the process of stabilization for highly basic self-slaking slags of ferroalloy production by various boron-containing materials were studied: tincalconite, colemanite, and ulexite (produced in Turkey). The viscosities and temperatures of crystallization for the initial boron-containing materials are determined. Under laboratory conditions, high-base slag melts were treated with boron-containing materials to obtain slags containing 0.25 and 0.5% B2О3. It was shown that the addition of boric anhydride to the studied slag melts extends the homogeneous-liquid state interval and reduces their viscosity by 1.2–1.6 times, therefore B2О3can be used as a tool for controlling slag mobility in industrial conditions. The industrial tests were conducted to stabilize the slag of low-carbon ferrochrome using powdered calcined, briquetted, and fused colemanite. After treatment, slags contained 43–47% CaO, 0.18–0.45% B2О3. The results of pilot-industrial experiments show that all applied boron-containing materials ensure slag stabilization and differ only in the degree of boron recovery. Fused colemanite showed the highest results in the recovery of B2О3(up to 98%), a commercial product was obtained which fully complies according to the technical characteristics with the requirements of Specification TU 0798-69-00186499-2014 “Crushed stone and sand from ferroalloy slags. Technical conditions.”
Keywords: ferroalloy, slag, self-slaking slag, stabilization, boron, two-calcium silicate
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