Abstract: A method of producing a rheologically stable concentrated aqueous suspension of a particulate alkaline earth metal carbonate which method comprises the following steps: (a) preparing a dilute aqueous suspension of the carbonate having a solids content of not more than 40% by weight; (b) dewatering the dilute aqueous suspension to form a carbonate suspension having a solids content in the range of from 45% to 65% by weight; (c) optionally mixing with the dewatered suspension formed in step (b) a dispersing agent for the carbonate to form a fluid suspension; (d) further dewatering the fluid suspension formed in step (b) by thermal evaporation under reduced pressure to raise the solids content of the suspension by a further differential amount of at least 5% by weight; and (e) after at least some of the dewatering in step (c) treating the suspension by a mechanical working process in which at least 1 kW.hr per tonne of carbonate on a dry weight basis is dissipated to refluidise the suspension.

Abstract: A method of producing an aqueous suspension of calcium hydroxide which comprises passing a gaseous flow incorporating particles of calcium carbonate through a calcining furnace thermally to decompose the calcium carbonate, delivering a flow of the decomposition products formed in the furnace comprising calcium oxide particles suspended in gas comprising carbon dioxide to a vessel wherein the calcium oxide particles are contacted with water to produce an aqueous suspension of calcium hydroxide and separating the aqueous suspension from the said gas.

Abstract: A method of removing solid particles, especially magnesium compounds, from the pores of the filter element of a tube pressure filter, by (A) washing the filter element whilst supported in the tube pressure filter with an aqueous cleaning solution containing a compound which reacts with the solid particles in the pores of the filter element to form a material which is at least partially soluble in said aqueous cleaning solution, and thereafter (B) washing the filter element whilst supported in the tube pressure filter with water or an aqueous solution of a soap or a detergent.

Abstract: A process is disclosed whereby aqueous slurries of particulate solid materials having a relatively low solids content are converted to aqueous slurries having a relatively high solids content. The process includes deflocculating a mixture comprising a particulate solid material and water with the aid of a chemical deflocculating agent to form a first aqueous slurry, partially dewatering the first aqueous slurry in, for example, a pressure filter to form a cake having a reduced water content as compared to the mixture and subjecting the cake to mechanical work which comprises at least one cycle of applying a stress to the cake and relaxing the applied stress to form a second aqueous slurry having an increased solids content as compared to the first aqueous slurry.