Abstract: A method of producing calcium carbonate from a waste sludge containing calcium carbonate and at least one silicate mineral. The method comprises the steps of: (i) incinerating the sludge to an ash in which at least 60% of the calcium carbonate present in the sludge is converted to free calcium oxide which is unreacted with the silicate mineral(s), (ii) optionally slaking the ash to convert at least a portion of the free calcium oxide therein to calcium hydroxide, (iii) treating either the ash from step (i) or the slaked ash from step (ii) with an aqueous solution of a polyhydroxy compound to provide a solution of dissolved calcium hydroxide, (iv) separating insoluble material from the solution of calcium ions obtained in step (iii), (v) dispersing carbon dioxide through the solution obtained from step (iv) so as to produce calcium carbonate, and (vi) separating the calcium carbonate produced in step (v).

Abstract: A method of producing calcium carbonate from a waste sludge containing calcium carbonate and at least one silicate mineral. The method comprises the steps of: (i) incinerating the sludge to an ash in which at least 60% of the calcium carbonate present in the sludge is converted to free calcium oxide which is unreacted with the silicate mineral(s), (ii) optionally slaking the ash to convert at least a portion of the free calcium oxide therein to calcium hydroxide, (iii) treating either the ash from step (i) or the slaked ash from step (ii) with an aqueous solution of a polyhydroxy compound to provide a solution of dissolved calcium hydroxide, (iv) separating insoluble material from the solution of calcium ions obtained in step (iii), (v) dispersing carbon dioxide through the solution obtained from step (iv) so as to produce calcium carbonate, and (vi) separating the calcium carbonate produced in step (v).

Abstract: A counter-balance weight for a modular safety rail includes a solid body of a compact shape which defines a substantially planar major surface which, in use, is intended to rest on a support surface The body defines a substantially linear through-bore for receiving an end of a spacer member. The through-bore extends continuously through the body in a direction substantially parallel with the substantially planar major surface of the body. The through-bore extends between a pair of end faces which, at least in part, are non-parallel end faces and the body further defines a screw-threaded aperture which extends through the body to intersect and communicate with the through-bore. The body may have a substantially triangular shape in transverse cross-section.

Abstract: A support foot for a modular safety rail system comprises a base plate having upper and lower surfaces and an outer periphery, a plurality of sockets positioned inwards of the periphery and extending from the upper surface for location of a vertical post, a plurality of webs provided at the upper surface and each extending from a socket towards the periphery, each web extending from the base plate to an upper edge surface of the web, the lower surface of the base plate having at least one recess whereby when one support foot is stacked on top of another at least one of a distal end of a socket and an upper edge of a web engages the recess to prevent lateral movement of the feet, and the upper edge surface of each web being able to support the lower surface of a superimposed support foot to resist toppling.

Abstract: A method of preparing an inorganic particulate material suitable for incorporation in a composition comprising a hydrophobic polymeric material includes the steps of (a) processing an aqueous suspension of an inorganic particulate material in the presence of a water soluble dispersing agent; (b) adding a surfactant to the particulate material; and (c) drying the particulate material. The inorganic particulate material to which the surfactant has been added may be further treated by addition thereto of a further surface treatment agent which is a hydrophobising surface treatment agent, eg. a carboxylic acid or salt thereof. The surfactant may be a non-ionic surfactant and may be added to the particulate material whilst in the form of a dispersed aqueous suspension. The further surface treatment agent may be added to the particulate material during or after the drying step (c).