A dissymmetric RN,N-dialkylamides of formula (I) in which: R.sup.1 represents a linear C.sub.1 to C.sub.4 alkyl, R.sup.2 represents a linear C.sub.1 to C.sub.10 alkyl, and R.sup.3 represents a linear or branched C.sub.6 to C.sub.15 alkyl, where R.sup.3 is different from a n-octyl, n-decyl, n-dodecyl, 2-ethylhexyl and 2-ethyloctyl group when R.sup.1 represents a n-butyl group and R.sup.2 represents an ethyl group. A method for synthesising the N,N-dialkylamides, and uses of same for extracting uranium and/or plutonium from an aqueous acid solution or for fully or partially separating the uranium from the plutonium contained in an aqueous acid solution and a solution resulting from the dissolution of spent nuclear fuel in nitric acid. A method for treating an aqueous solution resulting from the dissolution of spent nuclear fuel in nitric acid, which allows the uranium and the plutonium contained in the solution to be extracted, separated and decontaminated in a single cycle.

Provided are processes for extracting lithium and optionally nickel from a Nickel(II)/Lithium(I) (Ni.sup.2+/Li.sup.+) solution. The extraction is optionally performed in a series of steps with counterflow of aqueous and organic flows to thereby produce a lithium poor solution. The lithium poor solution may be treated so that remaining Ni in the lithium poor solution may be directly precipitated therefrom in the form of a Ni salt. Once complete, the process provides for recoverable nickel and/or lithium that may be recycled into batteries or sold for other uses.

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.

The present invention provides a method for easy and efficient recovery of high purity scandium from nickel oxide ore, the method comprising: an adsorption step for passing a scandium-containing solution through an ion exchange resin to adsorb scandium on the ion exchange resin; an elution step for eluting scandium from the ion exchange resin to obtain a post-elution solution; an impurity extraction step in which after the elution step, the scandium-containing solution is subjected to a first solvent extraction using an amine-based impurity extractant and is separated into a first aqueous phase containing scandium and into a first organic phase containing impurities; and a scandium extraction step in which the first aqueous phase is subjected to a second solvent extraction using an amide derivative-containing scandium extractant to obtain a second organic phase containing scandium.

The present invention provides a method for easy and efficient recovery of high purity scandium from nickel oxide ore, the method comprising: an adsorption step for passing a scandium-containing solution through an ion exchange resin to adsorb scandium on the ion exchange resin; an elution step for eluting scandium from the ion exchange resin to obtain a post-elution solution; an impurity extraction step in which after the elution step, the scandium-containing solution is subjected to a first solvent extraction using an amine-based impurity extractant and is separated into a first aqueous phase containing scandium and into a first organic phase containing impurities; and a scandium extraction step in which the first aqueous phase is subjected to a second solvent extraction using an amide derivative-containing scandium extractant to obtain a second organic phase containing scandium.

The proposed invention relates to processes for extracting and concentrating radionuclides and can be used in radiochemical technologies when treating liquid radioactive waste. The method for isolating americium from liquid radioactive waste and for separating americium from rare earth elements in a single extraction cycle involves joint extraction of americium and rare earth elements from a nitric acid radioactive solution with a neutral solution of an organic extraction agent in a polar fluorinated solvent; washing an obtained organic phase saturated with metals; and selective back extraction of americium, wherein the extraction agent for joint extraction is N,N,N,N-tetraalkylamide of diglycolic acid, and a solution for back extraction is a composition of 5-20 g/l of a complexone, 5-60 g/l of a nitrogen-containing organic acid and 60-240 g/l of a salting-out agent.

The proposed invention relates to processes for extracting and concentrating radionuclides and can be used in radiochemical technologies when treating liquid radioactive waste. The method for isolating americium from liquid radioactive waste and for separating americium from rare earth elements in a single extraction cycle involves joint extraction of americium and rare earth elements from a nitric acid radioactive solution with a neutral solution of an organic extraction agent in a polar fluorinated solvent; washing an obtained organic phase saturated with metals; and selective back extraction of americium, wherein the extraction agent for joint extraction is N,N,N,N-tetraalkylamide of diglycolic acid, and a solution for back extraction is a composition of 5-20 g/l of a complexone, 5-60 g/l of a nitrogen-containing organic acid and 60-240 g/l of a salting-out agent.

A process for recovering chromium from hexavalent chromium-containing wastewater comprises the following steps: (1) extracting hexavalent chromium in wastewater to an organic phase by using an extracting agent, and separating hexavalent chromium from a water phase, so as to acquire a hexavalent chromium-loaded organic phase; (2) reducing the hexavalent chromium-loaded organic phase by using an aqueous solution of an organic reducing agent, reducing hexavalent chromium into trivalent chromium, reversely extracting trivalent chromium into the water phase, and separating the organic phase from the water phase to acquire a solution of the trivalent chromium and a renewable organic phase, wherein the organic reducing agent is one or a mixture of alcohols, aldehydes and carboxylic acids having the carbon atom number ranging 1 to 3; and (3) performing solvent evaporation on the solution of trivalent chromium, catalyzing, and recovering the trivalent chromium.

A process for recovering chromium from hexavalent chromium-containing wastewater comprises the following steps: (1) extracting hexavalent chromium in wastewater to an organic phase by using an extracting agent, and separating hexavalent chromium from a water phase, so as to acquire a hexavalent chromium-loaded organic phase; (2) reducing the hexavalent chromium-loaded organic phase by using an aqueous solution of an organic reducing agent, reducing hexavalent chromium into trivalent chromium, reversely extracting trivalent chromium into the water phase, and separating the organic phase from the water phase to acquire a solution of the trivalent chromium and a renewable organic phase, wherein the organic reducing agent is one or a mixture of alcohols, aldehydes and carboxylic acids having the carbon atom number ranging 1 to 3; and (3) performing solvent evaporation on the solution of trivalent chromium, catalyzing, and recovering the trivalent chromium.

A method for recycling copper-indium-gallium-selenium (CIGS) waste is provided, comprising: vacuum distilling the CIGS waste to separate out selenium and obtain a distillation residue; electrolyzing the distillation residue to obtain copper and a remaining electrolyte containing indium and gallium; and separating indium and gallium from the remaining electrolyte containing indium and gallium. The method provides a novel route for recycling CIGS waste, the process is simple, and the environmental pollution caused by CIGS waste is decreased. Further, the residual raffinate can be reused in electrolyzing of the distillation residue as a copper sulfate electrolyte by adding appropriate amount of copper sulfate and sulfuric acid therein, such that the circulation of the copper sulfate electrolyte forms a closed cycle and the discharge of wastewater and pollution to the environment are reduced.