RAPID CHROMITE DISSOLUTION USING MANGANESE DIOXIDE-LITHIUM-SULFATE-SULFURIC-ACID MIXTURE-ESTIMATION OF ALUMINA IN CHROMITE FOR QUALITY-CONTROL ASSESSMENT

Proposed in this paper is a less labour-intensive method involving a m ixture (0.3 g MnO2 + 1.0 g Li2SO4 + 10 mL H2O + 20 mL of 36 M H2SO4 fo r 0.2 g sample) to decompose chromites for accurate and precise estima tion of alumina in chromite matrices for quality control (QC) assessme nt. Several international chromite samples, namely, CHR-BKg, CHR-Pt, I GS-30 and BCS-308 were analysed. Intermethod comparison studies reveal that the probability of results being different is less than (slight variation in case of CHR-BKg) 99% when two methods [ethylenediamine te traacetic acid (EDTA) titration and spectrophotometry using ammonium a urinitricarboxylate (aluminon)] were compared. It also shows that the proposed method yields better results than the most conventional route involving HClO4 decomposition used for similar purpose; hence can be used for QC programme and in the evaluation of reference materials.