The Noise Suppression Of Ionic Type Rare-earth Ore Leaching Process And Mechanism Research

During the leaching process of ion-absorbed rare earth, a lot of impurity ions would be contained in the lixivium and should be removed before precipitation process. It results that production costs increased, and quality of rare earth product and comprehensive recovery decreased. For these problems, lots of experiments were researched on to reduce impurity ions in leaching process and achieve low carbon exploitation.This research determined the best leaching conditions by different influencing factors on leaching rate of ion-absorbed rare earth in general leaching experiments.based on it, inhibiting experiments were carried out which adding more than20kinds of different inhibitors to lixivium. And the best kind of high efficient inhibitor was explored. The main results were as follows.In general ionic leaching tests, the best conditions could be expressed that the lixiviation process was leaching, and ammonium sulphate was chosen to be electrolytes medium, and extraction time was25h, and the concentration of leaching agent was4%, and the flow was2.5ml/min, and the ratio of solid and liquid was1:1, and the height of extraction column was7.1cm, and the density of mounted mineral was1.228g/ml, and water content of original ore was≤20%. The leaching rate could reach95%.In inhibiting impurities leaching tests, we could know that ammonium fluoride, ammonia, citric acid, ammonium sulfide, sodium sulfide, potassium thiocyanate, sodium pyrophosphate and triethanolamine could reduce the content of iron and aluminum ions, but they reduced the leaching rate of rare earth, too. So they were not chosen to be inhibitors. Adding the inhibitors of QWJ-02, QWJ-03, QWJ-04and QWJ-06could not only have little influence on the leaching rate of rare earth, but also reduced the content of iron and aluminum ions in the liquid. But they have a certain degree of toxicity and are harm to people and environment, so they were not be selected as inhibitors, too. When using QWJ-05, the leaching rate of rare earth reached to96%, and the removal rate of iron and aluminum ions reached to the average of92%and98%, and it has no toxicity. So it could be used as high efficient inhibitors in inhibiting and leaching of ion-absorbed rare earth ore. last, validation test was carried out and the results conformed to the study before.At the same time, this research suggested that inhibiting-leaching kinetics of ion-absorbed rare earth belongs to the diffusion-controlled kinetic, and the equation could be expressed as1-2/3*α-(1-α)2/3=K·t, and the apparent activation energy of the reaction was10.81KJ/mol.