Study On The Leaching-Migration Law Of Substances In The Leaching Process Of Ion-Adsorption Type Rare Earth Ore

In order to compare the leaching effect of ammonium sulfate and magnesium sulfate on ionic rare earth ores,and to improve the basic theory of ammonium sulfate and magnesium sulfate leaching system,so as to provide a theoretical basis for application,the closed leaching system is used in this paper to simulate the leaching process of ammonium sulfate,magnesium sulfate and compound leaching agent of ammonium sulfate and magnesium sulfate.We analyzed the changes in contents of rare earth,Al³⁺,Fe³⁺,Mg²⁺,NH₄⁺and SO₄^2-in minerals,aqueous leaching filtrate and acid leaching filtrate in different leaching columns after this process,the leaching effect and the leaching-migration law of ammonium sulfate,magnesium sulfate and compound leaching agent.The leaching-migration law of rare earth,Al³⁺,Fe³⁺,Mg²⁺,NH₄⁺and SO₄^2-in the leaching solution was studied after examining how these ions are leached in the process of ammonium sulfate leaching.Due to the negative adsorption by clay minerals,the total amount of rare earth in the ionic phase and the amount of rare earth in the aqueous leaching filtrate and acid leaching filtrate are less than that of rare earth in the raw minerals after a five-stage sequential leaching procedure.The rate of migration down of yttrium group,terbium group,cerium group were showed in descending order after leaching these rare earths.The aluminum in the raw minerals,which is in the form of water soluble aluminum and exchangeable aluminum,migrated down with the rare earth ions after being exchanged and leached by leaching agent of ammonium sulfate.It is difficult to leach the Fe³⁺from the minerals by pure water.After leaching,the total amount of Fe³⁺in the minerals increased first and then decreased,and the amount of Fe³⁺in acid leaching filtrate increased gradually.Mg²⁺leached from water soluble magnesium and exchangeable magnesium migrated down with the leaching solution.The addition of water can wash away the free SO₄^2-from the minerals,and the migration of SO₄^2-occurred in combination with rare earth and Al³⁺.The leaching-migration law of rare earth,Al³⁺,Fe³⁺,Mg²⁺,NH₄⁺and SO₄^2-in the leaching solution was studied after examining how these ions are leached in the magnesium sulfate leaching process.The finding shows that it the law of leaching-migration of ion phase rare earth,Al³⁺,Fe³⁺and SO₄^2-in the minerals after a five-stage sequential leaching procedure is similar to that of ammonium sulfate leaching.When magnesium sulfate is used for leaching,Mg²⁺will exchange NH₄⁺from the mineral into the leaching solution,and then migrate through sediment with the leaching solution.The leaching-migration law of rare earth,Al³⁺,Fe³⁺,Mg²⁺,NH₄⁺and SO₄^2-in the leaching solution was studied after examining how these ions are leached in the solution in the process of compound leaching agent leaching.The result shows that it is similar to that of ammonium sulfate and magnesium sulfate after a five-stage sequential leaching procedure.The activity of Mg²⁺is better than that of NH₄⁺,and Mg²⁺can be easily adsorbed by clay minerals and remain in minerals during leaching.The leaching-migration law of rare earth and main materials such as Al³⁺,Fe³⁺,SO₄^2-after leaching with different leaching agents was compared and analyzed.The concentration of rare earth ions in the leaching solution of magnesium sulfate is higher,and it is easier to exchange rare earth ions.When magnesium sulfate is used,there were more the leach residues,and more water is needed to wash in order to improve the yield of rare earth.At the same time,Mg²⁺is easily adsorbed on clay minerals,so it is difficult to wash off with water.After ammonium sulfate leaching,the free NH₄⁺in the minerals can be washed down by adding water.We can draw the conclusion that the leaching effect of ammonium sulfate is better than that of magnesium sulfate.