Method for extracting rare earth metals

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Overburden from surface coal mining in many regions can produce a rain runoff laden with selenium, in the selenate form, as well as rare earth elements (REEs). This occurs from rainwater leaching through exposed selenium/mineral-containing rocks in the overburden. The mineral-containing runoff water is caught in ponds, or deep mine water is collected from pools. Alternatively, leachate can be collected from coal gob or refuse piles. Extraction of REEs, as well as remediation of deleterious substances such as selenium, is performed by treatment with sulfur-modified iron (SMI) in a contact bed of an upflow reactor vessel. After a period of use of the SMI, the spent SMI is subjected to a recovery process for REEs.