GB692087A - Process for the production of a building material mixture - Google Patents

Abstract

A concrete composition is prepared by grinding or mixing one or more finely divided material from the group containing in chemical combination predominantly silicic acid, alumina and iron oxide the group consisting of both inert and latent-hydraulic materials with a second group consisting of one or more compound containing the oxide, hydroxide or carbonate of calcium or consisting of gypsum or anhydrous gypsum, in such proportions that if the first group contains a latent-hydraulic material, at least one inert material must also be present and also that in the final mixture the first group preponderates over the second group and silicic acid exceeds the alumina. Specified inert materials are combustion residues such as fly ash from coal, blast furnace dust, zinc ashes, filter waste from zinc ore flotation, brick dust, breccia ground residues, used sand from industrial processes; latent-hydraulic materials are oil schist residue, blast furnace scum slag and granulated blast furnace slag. The calcium compounds are hydrate of lime, quicklime, limestone and marl. A subsidiary process which gives an initial mixture for the main process comprises burning coal dust with a ground calcium compound. When the first group materials contain carbon the burning operation is conducted without using additional fuel, (see Group XII). A porous product is obtained when materials containing zinc are used in conjunction with the alkaline calcium compounds from the hydrogen liberated. The mixing water for the product may contain an acid which can dissolve limestone, or its salts, whereby a cauterization is effected.