METHOD OF MANUFACTURING LIGHT SANDS FROM CARBONIFEROUS BUDDLE SHALES, AND PRODUCTS OBTAINED THEREBY

摘要

1298283 Production of light sands; cellular mortars HOUILLERES DU BASSIN DU NORD ET DU PAS-DE-CALAIS and CHARBONNAGES DE FRANCE 24 April 1970 [28 April 1969] 19780/70 Headings C1A and C1H Light sands are produced from carboniferous shales in a process which comprises crushing the shales, isolating, by sieving, those grains having sizes in the range 1À25 mm. to 3 mm., and heat treating said grains before subjecting them to a final sudden expansive heating followed by cooling. Any grain agglutination may be eliminated by subjecting the product of the expansive heating to steam under pressure at the exit from the expansion chamber. The light sands produced are valuable for use in concretes, mortars and light aggregates and the residual dust can be utilized in brick manufacture. A particular application of the light sands of the invention is their use in association with fly ash to make very light mortars of the 400-700 kg./m.SP3/SP class with a binder such as cement or slaked lime. Such mortars can be substituted with advantage for cellular concrete of the gas-formed or foam-concrete type subsequent to casting or similar processing.