Evaluation of Compressive Strength of Manganese Oxidized Ore Briquettes: Effects of Compaction Pressure, Curing Time, and Percentage of Binder

Abstract

ABSTRACT Agglomeration is a common process to safely recycle wastes from the mining and metallurgical sectors. In this process, the mineralogical and chemical characteristics of manganese ores exert a significant influence on the reduction reactions within the electric furnace. Therefore, a systematic work has been done to evaluate the compressive strength of briquettes composed of manganese oxidized ore fines, ferromanganese dust, charcoal fines, and three different binders, bentonite, pregelatinized starch, and slaked lime + molasses. A response surface methodology was used to evaluate the effects of compaction pressure, curing time, and % binder, whose response was measured in terms of compressive strength. The results were assessed by Analysis of Variance and a regression model was generated. The study showed that briquettes with bentonite demonstrated an optimized compressive strength of 2.54 MPa with a compaction pressure of 52.5 MPa, 11 days of curing time, and 11.5% bentonite content. Briquettes with slaked lime + molasses achieved a compressive strength of 3.70 MPa with a compaction pressure of 62.12 MPa, a curing time of 24 days, and an addition of 16.2% slaked lime + molasses. For briquettes produced with pre-gelatinized starch, the design of the proposed variables resulted in a lack of fit to the model. Optimization studies revealed that briquettes made with bentonite and slaked lime + molasses are viable alternatives to replace oxidized lump ore in electric furnaces.