CHARACTERIZATION AND LEACHING FOR FINAL TAILING FROM NICKEL FLOTANTION PLANT OF MIRABELA MINE FROM BRAZIL
CARACTERIZAÇÃO; LIXIVIAÇÃO; FLOTAÇÃO; NÍQUEL; MINERAÇÃO.
In this work a study was conducted with samples of tailings from the nickel processing circuit of Mineração Mirabela. Chemical, physical, and mineralogical characterizations were performed using X-ray diffractometry, electron microscopy and electron microscopy, diagnosis of leaching of the main elements as a function of pH, release analysis and X-ray absorption spectroscopy (XANES and EXAFS). . It was found that part of the nickel is in solid solution with silicates and in sulfides. Prospective leaching tests were performed using sulfuric acid (with and without oxidizing agents), nitric acid, ferric chloride and alkaline reaction pretreatment at high temperatures. Then, detailed studies were performed on nickel leaching with sulfuric acid with pretreatment via alkaline fusion. This route proved to be advantageous, with 91% recovery of nickel due to the degradation of silicate in alkaline fusion. Sulfuric acid leaching by adding sodium nitrate as an oxidizing agent made it possible to solubilize mainly sulphide nickel, reaching recoveries of 80%. Kinetic tests were conducted using the optimal parameters, from the resulting curves, a homogeneous pseudo model was used for adjustment, numerically solved by the fourth order Runge-Kutta method. Activation energy was determined by the Arrhenius plot at 11.58 kcal / mol. Some reactor arrangements have been tested by simulating a set of five ideal semi-pilot scale tanks.