Leaching hydrodynamics of weathered elution-deposited rare earth ore with ammonium salts solution

• Published in: Journal of rare earths 2017-08, Vol.35 (8), p.824-830
• Main Author: 何正艳 张臻悦 池汝安 徐志高 余军霞 吴明 白如钰
• Format: Article
• Language: English
• Subjects: ammonium salts; hydrodynamics; NH4NO3; permeation velocity; rare earths; weathered elution-deposited rare earth ore; 浸出动力学; 淋洗; 盐溶液; 稀土矿; 铵盐; 风化壳; （NH4）2SO4
• ISSN: 1002-0721; 2509-4963
• DOI: 10.1016/S1002-0721(17)60982-7

In order to reveal the permeability rule of leaching agent solution and the effects of anions in the leaching process of weathered crust elution-deposited rare earth（RE） ores, the effects of ammonium concentration, temperature, particle size and porosity on the permeability were discussed in detail with（NH4）2SO4, NH4Cl and NH4NO3 as the leaching agent. It was found that the permeation velocity of ammonium salts increased linearly with the increase of hydraulic gradient. The seepage of ammonium salts solution in the RE ores followed Darcy’s law and displayed a laminar flow. The properties of the leaching agent solution and RE ores were the main factors that affect the permeability of RE ores. With the decrease of ammonium concentration and increase of temperature, the viscosity of solution decreased and the permeability coefficients of RE ores increased. And the effects of temperature on the viscosity and permeability were larger than ammonium concentration. The permeability of RE ores became worse with the decrease of particle size and porosity, and the particle size played a more important role compared with porosity. The permeability coefficient of RE ores increased and the viscosity of ammonium salts solution decreased in the order of（NH4）2SO4, NH4Cl and NH4NO3, implying that the penetrating power of anions increased in the order of SO42-, Cl- and NO3-. The results may play a vital role in improving the permeability of weathered crust elution-deposited RE ores.