ISOTHERMAL REDUCTION SMELTING OF MIXED CHROMITE-LATERITE SAMPLES WITH COCONUT CHARCOAL AS REDUCTANT UNDER ARGON ATMOSPHERE IN A VERTICAL ELECTRIC ARC FURNACE

The traditional production of stainless steel follows a long-way process which requires high energy consumption and increase emissions of CO and CO2 gases. This study aimed at assessing isothermal reduction smelting of additional mixed samples of chromite/laterite ores to produce directly Fe-Cr-Ni metal alloys in a single route manner. Chromite and laterite ores were obtained at Zambales and Surigao del Norte provinces, Philippines. Isothermal smelting was conducted to samples, 6/94 and 35/65 in addition to 12/88, 25/75 and 50/50, with coconut charcoal as reductant under argon atmosphere at 1600 ºC in one hour under a vertical electric arc furnace. Higher Cr contents are obtained at increasing percentages of chromite in the mixtures. Ni contents are in fluctuations at increasing laterite contents. Cr and Ni contents can be greatly attributed to the high dilution activity of iron in the metals. Higher recoveries of metal alloys are manifested at smelting 6/94, 35/65 and 50/50 with 93.67, 95.91 and 99.62%, respectively, at increasing chromite compositions. On the other hand, recoveries are decreasing at increasing laterite contents, clearly shown after smelting 12/88 and 25/75 samples with 69.70 and 78.99%, from that of 35/65 with 95.91%. The flushing out of volumes of slag, which is directly related to slag foaming, is believed to be the reason of the said decreasing recoveries. It can be recommended to use other carbon-based reductants and assess their impacts on the recovery of the metal alloys and on their Cr and Ni contents. Exploring other combinations of Philippines chromite and laterite can also be considered accounting their potential to obtain higher recoveries and higher Cr and Ni contents in the metal alloys. Slag foaming can also be further studied with parameters in this direct route smelting