Sustainable Mining and Metallurgy

The in situ leaching process of magnesium salt system is a new type of green mining process for ionic rare earth ore. Compared with the traditional ammonium sulfate leaching process, the new process avoids the problem of ammonia nitrogen pollution. However, the characteristic factors such as magnesium and TDS produced by the magnesium salt leaching mining process are also the key indicators of environmental protection control. Clarifying its environmental control requirements is the premise of environmental protection management and environmental impact assessment of the new process. In this paper, the environmental standards of magnesium at home and abroad were introduced. Through literature research, standard analogy, limit inversion and other methods, the characteristics of magnesium salt leaching process, the quality of regional water environment, the degree of harm of characteristic factors to the environment and human body were integrated. The relatively reasonable characteristic factor control requirements of magnesium salt leaching process were preliminarily put forward. It is suggested that the standard limit of magnesium in groundwater should refer to the standard of Poland (100mg/L), and the standard limit of magnesium in surface water should be 100mg/L; the emission control limit of magnesium in wastewater is suggested to be 500mg/L or not to set the emission limit, and the emission effect of magnesium is indirectly controlled through sulfate emission control.