The invention provides a method for preparing an actinide metal peroxide from a corresponding actinide metal oxide under solid reaction conditions.

A method of separating actinium and/or radium from proton-irradiated thorium metal. The thorium metal is irradiated to produce isotopes including thorium, actinium and/or radium. The resultant product is dissolved in solution and a selective precipitant is used to precipitate a bulk portion of the thorium. The precipitated thorium can be recovered. Chromatography is carried out on the remaining solution to remove residual thorium and to separate the actinium from the radium.

A method of separating actinium and/or radium from proton-irradiated thorium metal. The thorium metal is irradiated to produce isotopes including thorium, actinium and/or radium. The resultant product is dissolved in solution and a selective precipitant is used to precipitate a bulk portion of the thorium. The precipitated thorium can be recovered. Chromatography is carried out on the remaining solution to remove residual thorium and to separate the actinium from the radium.

A method of separating actinium and/or radium from proton-irradiated thorium metal. The thorium metal is irradiated to produce isotopes including thorium, actinium and/or radium. The resultant product is dissolved in solution and a selective precipitant is used to precipitate a bulk portion of the thorium. The precipitated thorium can be recovered. Chromatography is carried out on the remaining solution to remove residual thorium and to separate the actinium from the radium.

A method to activate U.sub.3O.sub.8 for conversion of this uranium oxide to hydrated UO.sub.4 via reaction with hydrogen peroxide H.sub.2O.sub.2, wherein the following successive steps are performed: a) an aqueous suspension is prepared containing a powder of U.sub.3O.sub.8 and hydrogen peroxide; b) the aqueous suspension containing a powder of U.sub.3O.sub.8 and hydrogen peroxide is contacted with ozone, whereby an aqueous suspension is obtained of a powder of activated U.sub.3O.sub.8; c) optionally the powder of activated U.sub.3O.sub.8 is separated from the aqueous suspension. A method to convert U.sub.3O.sub.8 to hydrated UO.sub.4 of formula UO.sub.4, nH.sub.2O where n is 2 or 4, comprising at least one step at which hydrogen peroxide H.sub.2O.sub.2 is added to the aqueous suspension of a powder of activated U.sub.3O.sub.8 obtained at the end of step b) of the activation method or to an aqueous suspension prepared by placing in suspension in water the powder of activated U.sub.3O.sub.8 obtained at the end of step c) of the activation method.

A method to activate U.sub.3O.sub.8 for conversion of this uranium oxide to hydrated UO.sub.4 via reaction with hydrogen peroxide H.sub.2O.sub.2, wherein the following successive steps are performed: a) an aqueous suspension is prepared containing a powder of U.sub.3O.sub.8 and hydrogen peroxide; b) the aqueous suspension containing a powder of U.sub.3O.sub.8 and hydrogen peroxide is contacted with ozone, whereby an aqueous suspension is obtained of a powder of activated U.sub.3O.sub.8; c) optionally the powder of activated U.sub.3O.sub.8 is separated from the aqueous suspension.

A method to convert U.sub.3O.sub.8 to hydrated UO.sub.4 of formula UO.sub.4, nH.sub.2O where n is 2 or 4, comprising at least one step at which hydrogen peroxide H.sub.2O.sub.2 is added to the aqueous suspension of a powder of activated U.sub.3O.sub.8 obtained at the end of step b) of the activation method or to an aqueous suspension prepared by placing in suspension in water the powder of activated U.sub.3O.sub.8 obtained at the end of step c) of the activation method.

Methods of producing peroxides of uranium may include preparing an aqueous solution comprising uranyl ions (UO.sub.2.sup.+2) in a vessel, bubbling ozone (O.sub.3) through the aqueous solution comprising the uranyl ions, and recovering the peroxide of uranium. The peroxide of uranium may comprise at least one of studtite (UO.sub.4.Math.4(H.sub.2O) or metastudtite (UO.sub.4.Math.2(H.sub.2O).