GB642945A - Improvements relating to glassy phosphate powder compositions and process of making the same - Google Patents

Abstract

Phosphate glasses for domestic water softening, prepared for example by heating dihydrogen monosodium orthophosphate and chilling to form a glass, having an alkali metal oxide: phosphorus pentoxide ratio at least 9 : 10, are rendered more easily soluble in water and increased in bulk, by moistening and thus rendering sticky the finely ground glass particles and mixing them with up to 10 per cent of one constituent of a chemical combination which in water generates a gas, drying the thus coated particles below 50 DEG C. and intimately mixing the other constituent of the combination in powder form with the treated particles. Alternatively equal amounts of ground glass may be treated, one with the first constituent and the other with the second. The gas-forming combination may be a combination of (a) a solid organic acid such as citric, salicylic, oxalic, maleic or tartaric acids, or an acid salt such as sodium pyrophosphate, sodium acid sulphate, monosodium dihydrogen orthophosphate, potassium acid tartrate &c., and (b) a substance which will react with the acid or acid salt in water to generate a gas, such as sodium carbonate, bicarbonate, sulphite or bisulphite. The phosphate glass so made is free-running and on adding to water the individual particles are repelled from each other by the gas generated and hence dissolve more quickly. Specification 642,944 is referred to.ALSO:Phosphate glasses for domestic water softening, prepared for p example by heating dihydrogen monosodium orthophosphate and chilling to form a glass, are rendered more easily soluble in water and increased in bulk by moistening and thus rendering sticky the finely ground glass particles and mixing them with up to 10 per cent of one constituent of a chemical combination which in water generates a gas, drying the thus coated particles below 50 DEG C and intimately mixing the other constituent of the combination in powder form with the treated particles. On addition to water the individual particles are repelled from each other by the gas generated and dissolve more quickly, Alternatively, equal amounts of ground glass may be treated, one with the first constituent and the other with the second. The gas-forming combination may be a combination of (a) solid organic acid such as citric, salycylic, oxalic, maleic or tartaric acids, or an acid salt such as sodium pyrophosphate, or acid sulphate, monosodium dihydrogen orthophosphate, potassium acid tartrate &c., and (b) a substance which will react with the acid or acid salt in water to generate a gas, such as sodium carbonate, bicarbonate, sulphite or bisulphite. Specification 642,944 is referred to.