Described herein is a process for stepwise leaching of all rare earth elements capable of forming peroxide and superoxide compounds, in particular cerium, lanthanum, neodymium, europium, from minerals containing these elements, namely from bastnaesites, orthites, chevkinites, and britholites.

A low-temperature leaching operation employs a raw, red mud slurry directly from aluminum production for an oxalic acid leaching of ferric oxalate. Residual calcium, titanium, aluminum and other rare earths are also recoverable in a secondary stream. Monitoring and control of the pH of the leach solution yields soluble ferric oxalate without high temperatures or specific radiation or light sources. Addition of iron powder results in precipitation of ferrous oxalate, isolated by magnetic separation from the iron powder which recirculates in the solution. Magnetite may then be produced by heating the ferrous oxalate in low pO.sub.2 conditions.

A low-temperature leaching operation employs a raw, red mud slurry directly from aluminum production for an oxalic acid leaching of ferric oxalate. Residual calcium, titanium, aluminum and other rare earths are also recoverable in a secondary stream. Monitoring and control of the pH of the leach solution yields soluble ferric oxalate without high temperatures or specific radiation or light sources. Addition of iron powder results in precipitation of ferrous oxalate, isolated by magnetic separation from the iron powder which recirculates in the solution. Magnetite may then be produced by heating the ferrous oxalate in low pO.sub.2 conditions.

The present disclosure provides Molecularly Imprinted Polymer (MIP) technology for selectively sequestering one or more target molecules from chemical mixtures. Also disclosed herein are MIP beads and methods of making and using thereof.

The invention relates to a method for removing metal and/or precious metal-containing depositions from substrates. The substrate is subjected to treatment with an organo amine protectant component P and an inorganic active component A. Component P may be formed in situ by reaction with component R. Component P is an organic amine and/or organic amine hydrochloride. Component A is an inorganic compound and component R is an organic compound that can be split along the CN bond by the component A into an organic amine. The metals in the form of organo-metallic complexes can be isolated and/or separated by means of different chemical reactions and/or biosorption.

The invention relates to a method for removing metal and/or precious metal-containing depositions from substrates. The substrate is subjected to treatment with an organo amine protectant component P and an inorganic active component A. Component P may be formed in situ by reaction with component R. Component P is an organic amine and/or organic amine hydrochloride. Component A is an inorganic compound and component R is an organic compound that can be split along the CN bond by the component A into an organic amine. The metals in the form of organo-metallic complexes can be isolated and/or separated by means of different chemical reactions and/or biosorption.

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.

Leaching aids, for example, when present in a leaching solution, and methods of using the leaching aids. The leaching aids can include one or a combination of compounds. The method of using the leaching aids can include a process of recovering metal from ore, for example, a process involving heap leaching, solvent extraction and electrowinning.

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.