国产精品视频一区二区三区四,亚洲av美洲av综合av,99国内精品久久久久久久,欧美电影一区二区三区电影

 文獻名： Ultrasound-assisted leaching of rare earths from the weathered crust elution-deposited ore using magnesium sulfate without ammonia-nitrogen pollution

 

作者： Shaohua Yin^a, Jiannan Pei^a, Feng Jiang^a, Shiwei Li^a, Jinhui Peng^a, Libo Zhang^a, Shaohua Ju^a, Chandrasekar Srinivasakannan^b

^a    Faculty of Metallurgical and Energy Engineering, Kunming University of Science and Technology, Kunming, Yunnan 650093, China

^b    Chemical Engineering Program, The Petroleum Institute, Abu Dhabi, P.O. Box 253, United Arab Emirates

 

摘要：The in situ leaching process of China's unique ion-adsorption rare earth ores has caused severe environmental damages due to the use of (NH4)2SO4 solution. This study reports that magnesium sulfate (MgSO4) as a leaching agent would replace (NH4)2SO4 by ultrasonically assisted leaching to deal with the ammonia-nitrogen pollution problem and enhance leaching process. At leaching conditions of 3 wt% MgSO4 concentration, 3:1 L/S ratio and 30 min, the total rare earth leaching efficiency reaches 75.5%. Ultrasound-assisted leaching experiments show that the leaching efficiency of rare earths is substantially increased by introducing ultrasound, and nearly completely leached out after two stage leaching process. Thus, ultrasonic-assisted leaching process with MgSO4 is not only effective but also environmentally friendly, and beneficial to leach rare earths at laboratory scale.