In　this　work，the　corrosivity，composition，phase　structure　and　occurrence　of　the　removed　residue，acid　leaching　residue，molten　salt　slags　were　studied.　First，the　effects　of　reaction　parameters（e.g.，leaching　time，pH　and　temperature）on　leaching　contents　of　heavy　metal　ions（e.g.　Cu，Zn，Pb，Cd，Ni，Cr，Be，Ba，As　and　Se）and　rare　earth　elements（e.g.　Dy，Er，Gd，Ho，Nd，Pr，Sm，Yb）were　investigated.　The　main　pollutants　in　those　three　slags，their　heavy　metal　leaching　toxicities　and　environmental　impacts　were　further　analyzed.　The　present　study　introduces　new　data　on　the　recycling　and　safe　disposal　of　rare　earth　waste　residues　in　China.　©　2024　Chinese　Society　of　Rare　Earths.　All　rights　reserved.