Sustainable Mining and Metallurgy

After years of mining ion-adsorbed rare earth deposits in Southern China by in-situ leaching process with ammonium sulfate as the leachant, the ammonia nitrogen pollution is looming large. Therefore, the new green ammonia-free mining process adopts the leachant of magnesium sulfate instead of ammonium sulfate to treat ion-adsorbed rare earth. To study the impact of this new mining process on environment, the complete coverage type rare earth ore blocks and barefoot type ore blocks were sampled respectively, and the test group and the control group were set up to determine the chlorophyll content and coverage of dicranopteris pedata, a typical plant, and the number of soil microbes. The study shows that there is no vast difference in vegetation growth, chlorophyll content and soil microbes between mines affected by leachant injection and surrounding unimpacted control points, indicating that the impact of green ammonia-free mining process on vegetation and soil microbes of a wide variety of ion-adsorbed rare earth mines is acceptable and this new mining process is proven practicable to protect the environment of various ion-adsorbed rare earth mines.