IMPACT OF ORGANIC ACID ADDITION ON THE FORMATION OF PRECIPITATED IRON COMPOUNDS

Abstract

In this work, acetic and citric acids were used along with ammonium chloride in the removal of iron from reduced Hatinh ilmenite. Iron removal was carried out at 70ºC, 4 liter/min of air flow rate, 7/1 of liquid/solid ratio and 0.5% NH4Cl as catalyst. After 9 hours, metallic iron was decreased from 30.3% in reduced ilmenite to 0.5% in synthetic rutile. The addition of 0.4% acetic acid into NH4Cl solution reduces removal time to 5 hours, residual metallic iron (RMI) was also 0.5%. The addition of 0.4% citric acid also reduces removal time to 5 hours, RMI was reduced to 0.33%. The rusting rate of metallic iron increased when acid concentration increased from 0.1 to 1%. The results indicated that acetic and citric acids could be used as additional catalysts along with NH4Cl in the removal of metallic iron in reduced ilmenite. The acid have the capability to form complexes with iron and also showed impact on the formation of precipitated iron compounds.