Verfahren zur Herstellung von hochreaktionsfaehigen Pulvern

1,262,340. Oxide powders. W. R. GRACE & CO. 23 April, 1969 [23 April, 1968], No. 20854/69. Headings C1A and C1N High surface area oxide powders composed substantially of particles having a diameter between 0À005 and 0À01 micron agglomerated together are prepared by grinding a precursor of the oxide comprising (a) a mixture of decomposable salts of different metals, .or (b) a decomposable salt of a single metal other than aluminium, or (c) a mixture of silica with a decomposable salt, in the form of a solid, slurry or solution in a fluid energy mill at a temperature of between -500‹ and 1400‹ F. By "decomposable" is meant that the salt decomposes to a solid oxide under the temperature and atmosphere in the mill. The oxide precursors of the examples include decomposable salts of Zr, Fe and Ti, such as the.nitrate, sulphate, carbonate, oxalate and formate, a mixture of silica and ammonium nitrate, and a mixture of decomposable salts of (i) aluminium and chromium, (ii) magnesium and aluminium in an atomic ratio of 1 : 2 to give a spinel of the formula Mg 2 AlO 4 , and (iii) copper and chromium, to give CuCr 2 O 4 .