Leaching Process Of Rare Earth Research Articles

Recovery of rare earth from bastnasite by ammonium chloride roasting with fluorine deactivation

The conventional methods (e.g., sulphuric acid roasting) for extracting rare earth (RE) from the bastnasite concentrate are inefficient and energy intensive, accompanied by serious environmental issues resulting from HF and SO 2 evolution. Direct application of chloride roasting process followed by hot water leaching could cause a significant loss (up to one-third) of RE to the tailings. This is because the RE fluorides formed from bastnasite decomposition are water-insoluble. A novel process is developed in this study to deactivate fluorine by adding magnesium oxide into the bastnasite decomposition prior to chloride roasting. The added magnesium oxide reacts with the fluorine in the bastnasite to form water insoluble magnesium fluoride. As a result, more RE elements are converted to RE oxides, thereby facilitating chloride roasting and RE leaching process. Consequently, RE recovery increased significantly (ca. 90%) with a high purity of RE oxide product (containing >94% RE oxide).

Recovery of rare earth from bastnasite by ammonium chloride roasting with fluorine deactivation

The conventional methods (e.g., sulphuric acid roasting) for extracting rare earth (RE) from the bastnasite concentrate are inefficient and energy intensive, accompanied by serious environmental issues resulting from HF and SO 2 evolution. Direct application of chloride roasting process followed by hot water leaching could cause a significant loss (up to one-third) of RE to the tailings. This is because the RE fluorides formed from bastnasite decomposition are water-insoluble. A novel process is developed in this study to deactivate fluorine by adding magnesium oxide into the bastnasite decomposition prior to chloride roasting. The added magnesium oxide reacts with the fluorine in the bastnasite to form water insoluble magnesium fluoride . As a result, more RE elements are converted to RE oxides, thereby facilitating chloride roasting and RE leaching process. Consequently, RE recovery increased significantly (ca. 90%) with a high purity of RE oxide product (containing >94% RE oxide).

Behavior of Cs on the monocrystalline points of Ta and Ta 2C : N.A. Gorbatyi and E.M. Riabchenko (Vol. 7, No. 4, p. 1150)

Magnesium sulfate was proposed to be leaching agent to deal with the ion-adsorption type rare earths ore to reduce or even eliminate ammonia–nitrogen emissions. The effects of temperature, particle size and stirring speed on rare earth leaching process and the leaching behaviors of the single rare earth element were investigated in order to reveal the rare earth leaching characteristics. Besides, the comparison of leaching effects between magnesium sulfate and ammonium sulfate was also studied. The results showed that the rare earth leaching process could be well described with inner diffusion control model and the apparent activation energy was 9.48 kJ/mol. The leaching behaviors of the single rare earth element were brought into correspondence with rare earths. Moreover, when the concentration of leaching agent was 0.20 mol/L, the rare earth leaching efficiency could all reach above 95% and the leaching efficiency of aluminum impurities could be restrained by 10% using magnesium sulfate compared with ammonium sulfate.