GB1178461A - Process for the Production of Expanded Materials and the Manufacture of Cellular Stone in accordance herewith - Google Patents

Abstract

1,178,461. Expanded natural silicate material. UTOLIT A.G. 17 Jan., 1967 [19 Jan., 1966; 2 Feb., 1966; 25 Feb., 1966; 19 March, 1966; 11 July, 1966], No. 2522/67. Heading C1M. An expanded cellular material is produced by pulverizing to a fineness having a Bleine number (surface area in cm.<2>/gm.) of at least 2500, either separately or as a mixture, a basic material composed of natural silicate, silicate earth or stone, the basic material having a silicate content of at least 40% by weight, and a fusion and blowing agent in the form of a powder produced by emulsifying carbon black in an aqueous solution of soluble glass (Na2- SiO3), optionally adding an inert carrier (e.g. powdered scrap glass) to the emulsion and drying and grinding the resultant mixture to form the blowing agent, forming a mixture of basic material and blowing agent where these are pulverized separately, and heating this mixture to 800-1200‹ C. to foam the material, and then cooling slowly to prevent recrystallization. Preferably, the blowing agent/basic material mixture is granulated immediately prior to the heating step. The basic material may be sands, quartz sand, molasse sandstone, pumice or pumice sand, lava earth or similar volcanic stones or mixtures thereof. A binding agent (preferably 1-10%) may be added to the mixture or to the basic material or blowing agent before mixing. Preferred binding agents are phenol-formaldehyde resins, furan resins, cement or plaster, or burnt brick material. After the granulation, a separator agent, preferably of the same material as the binding agent, may be added to the surface of the granules. The foaming may be carried out in a rotating kiln, or in moulds to obtain, e.g. tiles or pipes.