Hydrometallurgical systems, methods, and compositions are described in which organic amine-based lixiviants are utilized in the selective recovery of alkaline earth elements. The lixiviant can be regenerated and recycled for use in subsequent iterations of the process. Suitable lixiviant species include zwitterions, including zwitterion pairs that act as counterions to one another.

Compositions and methods are provided that provide recovery of metals such as copper, nickel, cobalt, indium, and other metals are recovered from mine tailings, in situ ore bodies, or postconsumer waste. An amine-containing lixiviant is utilized to generate an aqueous solution of the desired metal from insoluble salts present in the source material. Metals can be recovered and further purified by various processes, including extraction into an immiscible organic solvent, electrowinning, crystallization, and chemical reduction. Spent lixiviant can be regenerated and recycled back into the metal recovery process.

Hydrometallurgical compositions are described in which organic amine-based lixiviants and organic amine-based pre-lixiviants are utilized in the selective recovery of rare earth elements. The lixiviant species can be regenerated in situ, permitting the organic amine to be used in substoichiometric amounts.

Methods and compositions are described in which amine-based compounds are utilized in the recovery of rare earth elements from solution. The rare earth elements are recovered selectively and sequentially.

Disclosed herein is a method for extracting precious metals from supported catalysts. The precious metal in one embodiment is rhodium. The supported catalyst may be from equipment, such as a used catalytic converter. The method is carried out at low temperature, and does not require harsh conditions, such as the use of a strong acid. The method involves contacting the catalytic material with a polar molecule and a reactive gas.

Hydrometallurgical systems, methods, and compositions are described in which organic amine-based lixiviants are utilized in the selective recovery of alkaline earth elements. The lixiviant can be regenerated and recycled for use in subsequent iterations of the process. Suitable lixiviant species include zwitterions, including zwitterion pairs that act as counterions to one another.

Hydrometallurgical systems, methods, and compositions are described in which organic amine-based lixiviants are utilized in the selective recovery of alkaline earth elements. The lixiviant can be regenerated and recycled for use in subsequent iterations of the process. Multiple alkaline earth elements can be recovered from a sample in parallel or in serial applications of the disclosed methods.

Precious metals such as those of the platinum group can be effectively recovered from crystalline aluminosilicate supports, for example from spent catalysts, without appreciable degradation of the crystal structure by ion-exchange using a base metal ion containing medium and subsequent sequestration of the precious metal in elemental form on a nonionic cross linked borane reducing resin.

A method for extracting an alkali metal element comprises contacting a sample comprising a first alkali metal salt with a first lixiviant, the first lixiviant comprising a first amine cation and a first counterion, wherein the first alkali metal salt comprises a first alkali metal element, and wherein the first lixiviant is selected to react selectively with the first alkali metal salt. The method forms a depleted sample and a first supernatant comprising a first uncharged or charged amine, and a first soluble complex comprising a cation of the first alkali metal element and the first counterion. The method further transfers the first alkali metal element cation from the first supernatant, and regenerates the first amine cation by the addition of a first precipitant or salt forming agent.

The present applications relates to methods for the simultaneous leaching and extraction of precious metals. For example, the present application relates to methods of leaching and extracting gold and/or palladium from a substance comprising gold and/or palladium such as a gold- and/or palladium-containing ore in one step using a compound of Formula I:(I).

##STR00001##