The outdated production processes and techniques in the mining, dressing, smelting and separating of rare earth ores have severely damaged surface vegetation, caused soil erosion, pollution and acidification, and reduced or even eliminated food crop output. In the past, the outmoded tank leaching and heap leaching techniques were employed at ion-absorption middle and heavy rare earth mines, creating 2,000 tons of tailings for the production of every ton of REO (rare earth oxide). Although more advanced in-situ leaching method has been widely adopted, large quantities of ammonium nitrogen, heavy metal and other pollutants are being produced, resulting in the destruction of vegetation and severe pollution of surface water, ground water and farmland.
Light rare earth mines usually contain many associated metals, and large quantities of toxic and hazardous gases, waste water with high concentration of ammonium nitrogen and radioactive residues are generated during the processes of smelting and separating. In some places, the excessive rare earth mining has resulted in landslides, clogged rivers, environmental pollution emergencies and even major accidents and disasters, causing great damage to people's safety and health and the ecological environment. At the same time, the restoration and improvement of the environment has also heavily burdened some rare earth production areas.
(Source: Information Office of the State Council of the People's Republic of China) |