The present invention relates to use of an amino-containing neutral phosphine extractant of Formula I in extraction and separation of thorium, and a process of extracting and separating thorium using the amino-containing neutral phosphine extractant of Formula I,

##STR00001##

wherein, R.sub.1 and R.sub.2 are each independently selected from the group consisting of C.sub.1-C.sub.12 alkyl, R.sub.3 and R.sub.4 are each independently selected from the group consisting of C.sub.1-16 alkyl and hydrogen, and n is an integer of 1 to 8.

A continuous solvent extract process is provided for concentrating rare earth elements from leachates generated from coal sources. The process involves solvent extraction which utilizes an organic extractant mixed into an organic solvent.

An object of the present invention is to recover a minor metal and/or rare-earth metal. The present invention provides a method for recovering a minor metal and/or rare-earth metal from a post-chlorination residue in titanium smelting. The minor metal and/or rare-earth metal is one or more metal selected from the group consisting of Sc, V, Nb, Zr, Y, La, Ce, Pr, and Nd.

A method of recovering metal compounds from solid oxide fuel cell scrap includes processing the solid oxide fuel cell scrap to form a powder, digesting the processed scrap, extracting lanthanum oxide and cerium oxide from a solution containing the digested processed scrap, extracting a zirconium compound from the solution after extracting the lanthanum oxide and cerium oxide, and extracting scandium compound from the solution extracting the zirconium compound from the solution.

A continuous solvent extract process is provided for concentrating rare earth elements from leachates generated from coal sources. The process involves solvent extraction which utilizes an organic extractant mixed into an organic solvent.

An object of the present invention is to recover a minor metal and/or rare-earth metal.

The present invention provides a method for recovering a minor metal and/or rare-earth metal from a post-chlorination residue in titanium smelting.

The minor metal and/or rare-earth metal is one or more metal selected from the group consisting of Sc, V, Nb, Zr, Y, La, Ce, Pr, and Nd.

A method of recovering metal compounds from solid oxide fuel cell scrap includes processing the solid oxide fuel cell scrap to form a powder, digesting the processed scrap, extracting lanthanum oxide and cerium oxide from a solution containing the digested processed scrap, extracting a zirconium compound from the solution after extracting the lanthanum oxide and cerium oxide, and extracting scandium compound from the solution extracting the zirconium compound from the solution.

The present invention relates to use of an amino-containing neutral phosphine extractant of Formula I in extraction and separation of thorium, and a process of extracting and separating thorium using the amino-containing neutral phosphine extractant of Formula I, ##STR00001##
wherein, R.sub.1 and R.sub.2 are each independently selected from the group consisting of C.sub.1-C.sub.12 alkyl, R.sub.3 and R.sub.4 are each independently selected from the group consisting of C.sub.1-16 alkyl and hydrogen, and n is an integer of 1 to 8.

Proposed are a positive electrode active material using a spent battery leachate for secondary batteries and a method of preparing the same. Using a spent battery leachate enables the positive electrode active material for secondary batteries, the positive electrode active material having a composition of Li(Ni.sub.aCo.sub.bAl.sub.c)O.sub.2 (where a+b+c=1) including Ni, Co, and Al and being prepared from a precursor having a composition of Ni.sub.aCo.sub.b (where a+b=1), to be prepared. As a result, some raw materials can be replaced with the spent battery leachate when preparing the positive electrode active material for secondary batteries, thereby reducing manufacturing costs and solving environmental problems.