Abstract: Reactive derivatives of zirconium, are provided which are in the form of a pulverulent white, non-crystallized solid which is dry in appearance, and consist of metazironic acid, ZrO (OH).sub.2, accompanied by free or weakly bound water, some of the OH.sup.- ions being optionally replaced by halide ions. The ZrO.sub.2 content of these derivatives is from 60 to 92% by weight inclusive, the water content ranges from 3 to 40%, and the halide ion content can range up to approximately 5% by weight. The solid derivatives of the invention can be easily converted into usual reactive derivatives of zirconium by reaction with an aqueous solution of an acid.

Abstract: A process for the preparation of improved zirconium oxides comprising A) providing a zirconium oxide which has been produced by thermal decomposition of zircon followed by chemical digestion of the resultant silicate phases, B) reacting the zirconium oxide at high temperature with an alkali metal hydroxide or carbonate so as to form an alkali metal zirconate, C) hydrolyzing the resultant alkali metal zirconate so as to produce a suspension of zirconium oxide hydrate in a concentrated solution of alkali metal hydroxide, D) separating the zirconium oxide hydrate from the concentrated solution and washing the zirconium oxide hydrate which has been isolated, and E) drying the zirconium oxide hydrate at a temperature in the range of from 110.degree. to 570.degree. C.

Abstract: A process for the preparation of zirconia hydrate from zirconia by reaction of the latter with solid sodium hydroxide at 550.degree.-1,400.degree. C. to form Na zirconate; hydrolysis of the latter to form a suspension of zirconia hydrate in aqueous sodium hydroxide; separation of most of the aqueous sodium hydroxide; treatment of the zirconia hydrate containing residual aqueous sodium hydroxide with an ammonium salt; and separation, washing and dewatering of the purified zirconia hydrate obtained.The zirconia hydrate can be used for the preparation of zirconium compounds.

Abstract: The invention relates to the chemistry of zirconium.It relates particularly to a reactive zirconium oxide in the form of fine particles whose median diameter does not exceed 10 .mu.m, which has a structure chosen from the amorphous structure and the structure crystallized in the tetragonal form, the size of the elementary coherence regions in the latter case being between 10 and 30 nm, and which has a B.E.T. surface area of at least 30 m.sup.2 /g, and to a process for its preparation.Use in the field of ceramic materials.