Recuperação de minerais de altos valores em refratários siderúrgicos de pós-consumo.

Abstract

Refractory materials are of critical importance to various industrial sectors, particularly the steel industry, which accounts for 70% of consumption, followed by the cement industry with 9%, and non-ferrous metallurgy with 4%, among others. Over the years, a reduction in both production and specific consumption of refractory materials has been observed, mainly due to improvements in the operational parameters of end users and the development of new refractory materials with enhanced thermal and mechanical properties. Nevertheless, despite the decline in these indicators, certain challenges persist within the refractory sector. The main issues include the disposal methods of post-mortem refractory materials and the CO₂ emissions associated with the production of virgin raw materials. For instance, zirconia (ZrO₂) is noted for having the highest production cost and carbon emissions during its manufacturing process. Based on this scenario, the present study qualitatively investigates a hypothesis regarding particle size ranges that exhibit higher concentrations of zirconia (ZrO₂), tabular alumina (Al₂O₃-⍺), fused magnesia (MgO), and silicon carbide (SiC), derived from their respective post-consumer refractory products. Following four processing stages—comminution, screening, and particle size classification—it is hypothesized that minerals with higher hardness (ZrO₂, Al₂O₃-⍺, and SiC) tend to concentrate in coarser fractions, specifically above 9.5 mm. Meanwhile, fused MgO, with intermediate hardness, is found in higher concentrations in particle size fractions above 2.360 mm.