Disclosed is a method for manufacturing crystals of aluminates of one or more element(s) other than aluminium, referred to as “A. The method includes: placing starting reagents, including at least one aluminium element source and a source of the element(s) A that has a degree of oxidation of between 1 and 6, in suspension in a liquid medium, forming a suspension referred to as the “starting suspension”; milling the starting suspension at ≤50° C., in a three-dimensional liquid medium ball mill for ≤5 minutes; recovering, at the outlet of the three-dimensional ball mill, a suspension referred to as the “end suspension” including the starting reagents in activated form or crystals of aluminate of the element(s) A generally in hydrated form; if required, calcination of the end suspension when it includes the starting reagents in activated form, to obtain generally non-hydrated crystals of aluminate of the element(s) A.

The invention provides a method of producing a metal oxyhydride, capable of synthesizing the metal oxyhydride under reaction conditions close to atmospheric pressure, and excellent in productivity and cost. The method of producing a metal oxyhydride of the present invention includes reacting an oxide with a metal hydride in a hydrogen atmosphere. A non-oxygen element constituting the oxide comprises only one kind of non-oxygen element. A pressure condition of the reaction is 0.1 to 0.9 MPa, and a temperature of the reaction is 500 to 1000° C.

Disclosed is a method for manufacturing crystals of aluminates of one or more element(s) other than aluminium, referred to as A. The method includes: placing starting reagents, including at least one aluminium element source and a source of the element(s) A that has a degree of oxidation of between 1 and 6, in suspension in a liquid medium, forming a suspension referred to as the starting suspension; milling the starting suspension at 50 C., in a three-dimensional liquid medium ball mill for 5 minutes; recovering, at the outlet of the three-dimensional ball mill, a suspension referred to as the end suspension including the starting reagents in activated form or crystals of aluminate of the element(s) A generally in hydrated form; if required, calcination of the end suspension when it includes the starting reagents in activated form, to obtain generally non-hydrated crystals of aluminate of the element(s) A.