Abstract: A process for preparing ceramic powders suitable for pressing into articles comprises the dispersing of a particulate ceramic, preferably of particle size below 1 .mu.m, in water in the presence of ammonia or an alkylamine having a boiling point below that of water and spray - drying the dispersion to give powders. The process is particularly applicable to zirconia and gives rise to fine, free-flowing powders which can be processed into articles of uniform density.

Abstract: The invention concerns processes for the preparation of zirconium compositions which on calcination form zirconia. The zirconium compositions are prepared by the addition of an ammonia source to an aqueous zirconium sulfate solution to give a solution pH in the range of from 0.1 to 2.5 and preferably 1.0 to 2.0. The zirconium composition precipitated from solution appears crystalline, is readily collected by filtration and has low levels of metallic impurities. Therefore, the process of the invention may be used to advantage in the purification zirconium compounds.The invention also includes the zirconium compositions and processes for the purification of zirconium compounds including zirconia.

Abstract: A transition metal composition has the composition M.sub.m,X.sub.p,TYn'Z where M is a metal of Groups Ib, IIa, IIIb, VIIa or VIII of the Periodic Table, X is an anion, T is a transition metal of Groups IVA--VIA of the Periodic Table, Y is an anion, Z is a melt-producing compound, m' is greater than zero and less than 100, n' is greater than zero and less than 8 (m'+1), and p' is m' x(valency of M)/(valency of X). The compositions of this type may be transformed into a liquid by heating and the hot liquid sprayed and the spray cooled. The sprayed material has a useful particle form and may be used as a component of a polymerization catalyst to polymerize an unsaturated monomer such as ethylene.

Abstract: A transition metal composition is obtained by treating at least one particulate support material with at least one organomagnesium compound, at least one cleavage agent and at least one transition metal compound of Groups IVA, VA or VIA of the Periodic Table. The support material is typically a metal oxide, such as alumina or silica. The orgaomagnesium compound is typically a dialkyl magnesium compound such as dibutyl magnesium. The cleavage agent may be an amine, a thioalcohol, an ester, a carboxylic acid or particularly an alcohol such as n-butanol. The transition metal compound is added after the organomagnesium compound and the cleavage agent and is typically titanium tetrachloride. The product may be used as a catalyst component to polymerise an olefine monomer such as ethylene.

Abstract: A component for an olefin polymerization catalyst which is the product of treating a particulate support material with (a) an organo-magnesium compound, (b) an aluminium compound e.g. ethyl aluminium dichloride, (c) an organometallic compound of general formula R.sub.m MX.sub.p wherein M is a metal of Groups IA, IIA, IIB, IIIB, VA or VIA of the Periodic Table, R is a hydrocarbyl or substituted hydrocarbyl group, X is a singly charged anionic ligand or a monodentate neutral ligand, m is an integer up to the highest valency of the metal M and p is 0 or an integer up to 2 less than the valency of the metal M, e.g. zirconium tetrabenzyl, and (d) at least one transition metal compound of Groups IVA, VA or VIA, e.g. titanium tetrachloride. The catalyst component can be used to effect copolymerization of ethylene with an alpha-olefin monomer such as butene-1 in a fluidized bed reactor.

Abstract: A component for an olefin polymerisation catalyst which component is the product of treating a particulate support material with (a) an organomagnesium compound, (b) a transition metal compound of Groups IVA, VA or VIA, e.g. bis-butoxy titanium dichloride, (c) a pacifying agent, e.g. HCl and (d) optionally an aluminium compound, e.g. ethyl aluminium dichloride, an organometallic compound, e.g. zirconium tetrabenzyl, a halogenating agent e.g. silicon tetrachloride, or a Lewis Base compound, e.g. ethyl benzoate.