Leaching and Kinetic Modeling of Pyrite Cinder in Sulphuric Acid

Pyrite cinder has often been utilized for the preparation of pigments, water purification materials and other materials including sponge iron powder, recovering iron, iron oxide red, ferrous sulfate and even bricks.In this work, orthogonal experiments were carried out to optimize the leaching conditions of pyrite cinder containing 48.94 % Fe, 13.9 % acid insoluble substance, 0.64 % Al2O3, 0.35 % Cu, 1.3 % S and 3.6 % CaO and then the corresponding kinetic equation was proposed.Effects of sulphuric acid concentration, excess coefficient, reaction temperature and reaction time on the leaching ratio were investigated.Statistical analysis indicates that the influence of the four factors on the leaching ratio is in the following sequence: reaction temperature, reaction time, excessive coefficient and sulphuric acid concentration.Furthermore, the optimized reaction conditions are obtained as reaction temperature 100 ºC, reaction time 3 h, excessive coefficient 1.05 and sulphuric acid concentration 8 M. We also explored the reaction kinetics and the corresponding kinetic equation has been proposed.The reaction of pyrite cinder in sulphuric acid medium fits the surface chemical reaction model.The kinetics equation was obtained with apparent activation energy of 38.69 kJ/mol.