Abstract: A method of environmental cleanup by producing an autoclaved aerated cement building material (termed AAC) by a process that uses the available silica sand and other raw materials in mine tailings, in particular copper mine tailings from porphyry copper mines. The process minimizes the need for processed silica sand and other raw materials, normally used in the production of the AAC building material. The lightweight AAC building material produced from the mine tailings has excellent thermal insulation properties, sound absorption and other desirable construction qualities comparable to AAC building material produced using processed silica sand, i.e. from non-mine tailings raw material sources.

Abstract: Smoke purification waste materials (SPW), rich in lime, are mixed with a product containing at least 60% silica and/or aluminum to bring the pH to a value of between 7 and 11.5 and with a quantity of water of between 15% and 160% of the weight of the waste materials and said product. In practice, the ratio of SiO.sub.2 and Al.sub.2 O.sub.3 over CaO must be at least equal to 0.8. Solid compounds are obtained that are virtually insoluble in water and that are non-pollutant.

Abstract: A method is shown for stabilizing sulfate bearing soils in which a silica compound is incorporated into the soils with the soils being further stabilized by the application of lime. The silica compound can be either an amorphous, flume silica, a crystalline silica, a silica gel, sodium silicate, potassium silicate or combination thereof. The silica compound and lime can be incorporated into the soils in a single step.

Abstract: The present invention provides a cement setting accelerator comprising 100 parts by weight of a sintered body, 5 to 70 parts by weight of an alkali metal carbonate powder and at most 170 parts by weight of a lime powder and a method of manufacturing the same. The sintered body contains a predetermined ratio of 3CaO.2Na.sub.2 O.5Al.sub.2 O.sub.3, Na.sub.2 SO.sub.4 and Na.sub.2 O.Al.sub.2 O.sub.3. Alternatively, a predetermined ratio of 3CaO.2Na.sub.2 O.5Al.sub.2 O.sub.3, Na.sub.2 SO.sub.4 and 4CaO.3Al.sub.2 O.sub.3.SO.sub.3 are contained in the sintered body. Further, a raw material mixture, which is not sintered and equal in the chemical composition to the sintered body noted above, may be used in place of the sintered body. Setting and hardening of a cement paste is markedly promoted by adding a small amount of the cement setting accelerator of the present invention to the cement paste.

Abstract: An asbestos-free insulating material suitable for use in molten metal casting is disclosed. The material is made from a mixture comprising lime, siliceous component, wollastonite, inorganic fiber and pitch based graphite fiber. The mixture is mixed with water to form a slurry, shaped, heated in the presence of steam, and dried to remove free water.

Abstract: Wollastonite acid treated and dried to pacify the surface processes more uniformly in subsequent reactions or remains inert when used as a filler. Phosphate cements prepared with the pacified wollastonite or similar calcium silicates exhibit improved strength and scratch resistance.

Abstract: A paste with improved workability is formed from at least 20% Portland cement. The paste when cured under ASTM conditions crystallizes into a substantially homogeneous mass of monolithic crystals of calcium silicate hydrate exhibiting a unique crystalline structure and having improved compressive strength.