Discussion on hazardous trace elements precipitation process in coal gangue

Introducing the concept of product life cycle in LCA(life cycle assessment),trace elements precipitation process was studied systematically in the whole life cycle of coal gangue as a by-product of coal mining.The results show that trace elements in coal gangue have a long-term course which is shown as precipitation-enrichment-precipitation in the whole period of coal gangue.With increase of weathering degree,environmental impact of coal gangue is gradually strengthened.