Reaction Kinetics for the Acid Leaching of Iron Oxides in Thermal Pretreated Partially Laterized Khondalite Rocks for Industrial Applications

摘要

Partially Laterized Khondalite (PLK) rocks are the waste materials generated during mining of bauxite and can be utilized as a valuable material for different industries like filler, ceramic and refractory after reducing the discolouring elemental impurity (iron oxide) present in these waste rocks. The main aim of the present investigation is to develop a flowsheet which supports the concept of "zero waste" and advocates today's waste is tomorrow's resource for filler and refractory industrial applications. In view of this, an attempt is made to develop a flowsheet on PLK rock sample to obtain superfine particles suitable for filler industries by stage crushing and classifying (using hydrocyclone) followed by calcinations at 1223 °K for one hour. The product obtained from superfine calcined nonmagnetic sample after hydrochloric acid leaching has the ceramic properties (ISI) which is suitable for filler/ceramic industries. The optimized conditions for leaching are: 6 molar hydrochloric acid, 373 °K and 60 minutes leaching time. The apparent activation energy is 53.8 kJ/mol (Fl model) and 59.5 kJ/mol (R3 model), which is much less compared to leaching of iron from bauxite.