1977 Volume 63 Issue 2 Pages 338-344
Chemical analysis of metallic chromium and iron contained in semi-reduced pellet produced in ferrochromium factory was studied. Metallic Cr and Fe form complex carbide which is easily dissolved in concentrated H2SO4. However, when acid concentration was high, higher analytical values of Cr and Fe were obtained because of the dissolution of Cr and Fe from unreacted chromite ore which was contained in the semireduced pellet. H2SO4 (1+3) was most suitable to fully recover metallic Cr and Fe preventing the dissolution of chromite. Another important point was to put a condensation cooler over a beaker to maintain constant volume and concentration of acid during heating period. The boiling point of H2SO4 (1+3) was kept to 111°C. Under this condition being maintained for 30 minutes, the best result was obtained. The proposed method had no bias among four laboratories and precision of the method was as follows; for metallic Cr, the standard deviation was 0.15% to mean value of 13.6%. for metallic Fe, the standard deviation was 0.20% to mean value of 11.0%.
