| 摘要 |
Mixtures of tetrasodium pyrophosphate and sodium metaphosphate having a predetermined hydrogen ion concentration in aqueous solution are obtained by mixing stoichiometrically proportioned amounts of different sodium orthophosphates, or of orthophosphoric acid with the sodium salt of a replaceable acid, heating the mixture to the melting-point, and quickly cooling, as by pouring the molten mass on a cold metal surface in thin layers. The mixture to be treated may consist of mono- and disodium orthophosphates, or of orthophosphoric acid and sodium carbonate, and equations are given whereby mixtures of the pyro-and metaphosphates in any determined proportions may be obtained. A diagram is furnished showing the melting points of the various mixtures and their pH value in solution, the latter value ranging from 6,4 to 10. The products may be used for controlling the pH value of water solutions, and particularly for treating boiler waters as they give the desired alkalinity and exhibit a delayed precipitating action towards the alkaline-earth metal salts.ALSO:The hydrogen ion concentration of water solutions is controlled by the use of mixtures of tetrasodium pyrophosphate and sodium metaphosphate prepared by mixing stoichiometrically proportioned amounts of different sodium orthophosphates, or of orthophosphoric acid with the sodium salt of a replaceable acid, heating the mixture to the melting point, and quickly cooling, as by pouring the molten mass on a cold metal surface in thin layers. The mixture to be heated may consist of mono- and disodium orthophosphates, or of orthophosphoric acid and sodium carbonate, and equations are given whereby mixtures of the pyro- and meta-phosphates in any determined proportions may be obtained. A diagram is furnished showing the melting points of the various mixtures and their pH value in solution, the latter value ranging from 6.4 to 10. |
