Abstract: A process for the production of a shaped article of a ceramic material in which a composition comprising particulate ceramic material and a liquid medium is shaped, the liquid medium is removed from the shaped composition, and the composition is heated to sinter the particles of ceramic material in which the composition is subjected to high shear mixing such that in the shaped article which is produced the mean maximum size of flaw is less than 25 microns. Also, a shaped article of sintered particulate ceramic material in which the mean maximum size of flaw is less than 25 microns and in which the minimum dimension of the shaped article is in excess of 0.1 mm.

Abstract: Acid water containing toxic levels (>0.1 ppm) of aluminum is treated to dissolve therein both silicate ions in an amount to create a solution containing at least 40, preferably at least 100, micromoles per liter of silicon and a silicon:aluminum ratio (based on metals) of at least about 6:1 and preferably 10:1 in the water to form a non-toxic complex with aluminum and alkali or alkali metal ions to increase the pH of the water. The preferred treatment agent is a hydraulic calcium silicate, in the form of cement clinker, optionally silicate-enriched with a soluble silicate.

Abstract: A process for the production of a fibre-reinforced ceramic composite by forming a precursor structure comprising a matrix of a composition comprising particulate ceramic material, liquid diluent and organic binder and fibres within the matrix, in which the fibres are formed from a composition comprising particulate ceramic material, liquid diluent and organic binder, and heating the precursor structure in order to evaporate the liquid diluent, decompose the organic binder and sinter the particles of ceramic material in both the matrix and the fibres. Also, a precursor structure as described. The ceramic composite may have a density of 95% or more of the maximum theoretical density.

Abstract: An agent for the treatment of water containing dissolved aluminum comprises a particulate alkali metal or quaternary ammonium silicate, the particles having a coating of a water-insoluble silicate over at least a part of their surface, and a process of treating water which comprises dissolving the agent in the water.

Abstract: An agent for the treatment of water containing dissolved aluminum comprises a particulate alkali metal or quaternary ammonium silicate, the particles having a coating of a water-insoluble silicate over at least a part of their surface, and a process of treating water which comprises dissolving the agent in the water.

Abstract: Process for production of a ceramic material, e.g. a carbide, nitride, boride or silicide, by reacting at least one compound of a metallic or non-metallic element having two or more groups reactive with hydroxyl groups with at least one organic compound having two or more hydroxyl groups to form an oxygen-containing polymeric product, heating the polymeric product to produce a coked product containing carbon and an oxide of the metallic or non-metallic element, and heating the coked product to produce a ceramic material, in which the proportion by weight of carbon to the oxide of the metallic or non-metallic element in the coked product is in the range from 50% to 150% of the proportion which is theoretically required to produce the ceramic material.

Abstract: A silicon carbide fibre, which may have a mean crystallite size of greater than 500A, in which the silicon carbide constitutes greater than 90% by weight of the fibre, and in which the fibre is substantially homogeneous across a transverse section of the fibre. The fibre may be produced by a process which comprises forming a fibre from a homogeneous mixture comprising particulate silicon carbide dispersed in a solution of an organic polymeric material in a liquid medium, and heating the fibre at elevated temperature in order to decompose the organic polymeric material and to sinter the particles of silicon carbide.

Abstract: A process for the production of a fibre-reinforced ceramic composite by forming a precursor structure comprising a matrix of a composition comprising particulate ceramic material, liquid diluent and organic binder and fibres within the matrix, in which the fibres are formed from a composition comprising particulate ceramic material, liquid diluent and organic binder, and heating the precursor structure in order to evaporate the liquid diluent, decompose the organic binder and sinter the particles of ceramic material in both the matrix and the fibres. Also, a precursor structure as described. The ceramic composite may have a density of 95% or more of the maximum theoretical density.

Abstract: A process for the production of a precursor which is a polymeric material comprising at least one metallic or non-metallic element, oxygen and carbon and from which a ceramic material, e.g. a carbide, nitride, boride, or silicide, may be produced by pyrolysis, which process comprises reacting(1) a first reactant which comprises a compound or compounds of at least one metallic or non-metallic element having two or more groups reactive with hydroxyl groups, and(2) a second reactant which comprises at least one organic compound having two or more hydroxyl groups,said reaction being effected in a liquid medium in which the reactants are soluble and/or dispersible and in which the polymeric material which is produced by the reaction is insoluble or in which the polymeric material may be caused to be insoluble, precipitating the polymeric material in the liquid medium in particulate form, and recovering the polymeric material from the liquid medium in particulate form.

Abstract: Process for production of a ceramic material, e.g. a carbide, nitride, boride or silicide, by reacting at least one compound of a metallic or non-metallic element having two or more goups reactive with hydroxyl groups with at least one organic compound having two or more hydroxyl groups to form an oxygen-containing polymeric product, heating the polymeric product to produce a coked product containing carbon and an oxide of the metallic or non-metallic element, and heating the coked product to produce a ceramic maerial, in which the proportion by weight of carbon to the oxide of the metallic or non-metallic element in the coked product is in the range from 50% to 150% of the proportion which is theoretically required to produce the ceramic material.

Abstract: A process for the production of a refractory compound, e.g. a carbide or nitride, of a metallic or non-metallic element, by reacting a mixture of a compound of the metallic or non-metallic element having at least two groups reactive with hydroxyl groups and an organic compound having at least two hydroxyl groups to produce an oxygen-containing polymeric product, and pyrolysing the polymeric product, e.g. in an inert atmosphere to produce a carbide or in an atmosphere of reactive nitrogen compound to produce a nitride, in which the reaction mixture contains an aluminium compound containing at least one group reactive with hydroxyl groups.The presence of the aluminium compound in the reaction mixture leads to an increase in the proportion of carbon in the product initially produced by pyrolysis, and to a higher purity in the refractory compound which is ultimately produced.

Abstract: A process for the production of a refractory boride or silicide which comprises producing an oxygen-containing polymeric product by reacting a compound of the metallic or non-metallic element having two or more groups reactive with hydroxyl groups and a compound of boron or silicon having two or more groups reactive with hydroxyl groups with an organic compound having two or more hydroxyl groups and heating the polymeric product in an inert atmosphere to pyrolyse the polymeric product and produce a refractory boride or silicide of the metallic or non-metallic element.

Abstract: A homogeneous composition comprising(1) at least one particulate ceramic material, and(2) a liquid medium, in which the composition comprises at least 50% by volume of particulate ceramic material, in which the particulate ceramic material and liquid medium are selected such that a test composition has a friction coefficient of less than 0.2, and in which the particulate ceramic material has a mean aspect ratio of less than 1.70, a shaped article produced from the composition, a shaped article from which the liquid medium has been removed, and a product in which the particles of ceramic material have been sintered.

Abstract: A fluid fertilizer composition based essentially on potassium chloride and an ammonium phosphate prepared by a process which comprises comminuting a solid substance containing potassium chloride and ammonium phosphate by grinding in the presence of a saturated solution of solid in a liquid in which the solid has a solubility greater than 1% by weight, the mixture of the solution and the solid being in fluid condition with the solid being a separate phase during grinding and the solution having dissolved therein an additive which is a crystal growth inhibitor for the solid whereby crystal growth is inhibited at both existing crystal surfaces and new crystal surfaces created by the breaking down of relatively coarse particles.

Abstract: A cementitious composition comprising hydraulic cement, not more than 25% of water by weight of the composition, and water soluble or dispersible (co)polymer in a proportion of 1 to 15% by weight of the hydraulic cement in the composition, the cement and (co)polymer being selected such that a test composition comprising 100 parts by weight of cement, 5 parts by weight of (co)polymer, and 16 parts by weight of water when extruded in a capillary rheometer undergoes an increase of at least 25% in shear stress when a ten-fold increase in the shear rate of the test composition from the capillary of the rheometer is effected. Also a cementitious product produced by setting of the composition. The (co)polymer is preferably a partially hydrolyzed poly (vinyl acetate). The cementitious product may have a flexural strength in excess of 100 MPa.

Abstract: A coated particulate filler having bound thereto a material comprising an acidic group reactive with the filler and a sulphur-containing group which is not reactive with the filler but which is decomposable to a sulphur-containing species which is capable of taking part in a sulphur-based curing reaction, a composition containing the filler and an organic polymeric material which contains ethylenic unsaturation and which is curable by reaction with sulphur, a process for producing the coated particulate filler, and a process for producing the composition.

Abstract: A cementitious composition comprising(a) at least one hydraulic cement,(b) water,(c) at least one polymeric water-soluble or water-dispersible additive which is capable of aiding in the processing of the composition, and(d) at least one particulate material insoluble in the composition and having an ultimate particle size of less than 0.1 micron,and a cement product produced therefrom.

Abstract: A cementitious product produced by setting of a composition comprising a mixture of at least one hydraulic cement and water not more than 2% of the total volume of the product comprising pores of maximum dimension exceeding 100 microns and preferably not more than 2% of the total volume comprising pores exceeding 15 microns in maximum dimension, the product preferably having a flexural strength of at least 40 MPa.

Abstract: A hydraulic cement characterized by the particle size distribution of the hydraulic cement being multi-modal, preferably bimodal or trimodal, and in which preferably there are present two or more distinct bands or modes of particle sizes and in which the total weight of particles of intermediate size does not exceed 20% of the total weight of the particles in the bands or modes adjacent thereto, and a cement composition comprising the hydraulic cement and not greater than 25% of water by weight of the hydraulic cement.

Abstract: A hydraulic cement composition comprising a mixture of at least one particulate hydraulic cement and water in which the weight average mean particle size of the particles of the cement is less than 20 microns and in which the proportion of water is not greater than 30% by weight of the hydraulic cement in the composition, the cement being preferably substantially free of particles having a size above 20 microns and the proportion of water being preferably not greater than 20% by weight.