Principle of hydration and measurement of sodium tripolyphosphate

Anhydrous sodium tripolyphosphate is reacted with water to produce pentasodium containing 6 water of crystallization.
This is an exothermic reaction, and the different structures are different from the heat released by the pentas of the crystalline form. There are two crystal forms of anhydrous sodium tripolyphosphate, one is type I (or type a, high temperature type), and the other type is type II (or type B, low temperature type). Among them, type I has a hydration heat release of 49.2 KJ/g, type II has a hydration heat release of 45.1 Kj/g, and the produced pentasodium hexahydrate is a cubic column crystal, which is dehydrated and decomposed into pyrophosphorus tetrasodium and orthophosphate at 70 ° C or higher. The synthesis of sodium tripolyphosphate was re-formed at above 120 °C.

The hydration of anhydrous sodium triphosphate can be carried out in any environment with water (such as wet air, pure water, aqueous solution, etc.), in order to compare its hydration characteristics (mainly characterized by very slow hydration), it is necessary to The combined speed of sodium polyphosphate was measured. Since the hydration process of pentasodium is an exothermic reaction, the hydration rate can be obtained by measuring the rate of change of the amount of heat released over time. In industrial production, direct measurement of heat is difficult, and it is usually indirectly reflected in the change in the temperature of the material in the adiabatic vessel (the determination of the Na5P3O10-I content in actual production is carried out by this method). Under the specific measurement conditions, the measurement results are related to various factors such as the heat insulation performance, the stirring state, the medium, the temperature, and the concentration of the container. Therefore, it is necessary to fix the measurement conditions in order to make the measurement of the hydration speed meaningful.

Zhengzhou Yucai Phosphate Chemical Factory specializes in the production of sodium hexametaphosphate, sodium pyrophosphate, sodium tripolyphosphate, disodium hydrogen phosphate, industrial phosphoric acid, trisodium phosphate, aluminum dihydrogen phosphate, solid aluminum dihydrogen phosphate, liquid dihydrogen phosphate Aluminium, sodium dihydrogen phosphate and other phosphate series products, after more than 30 years of continuous pursuit and development, relying on skilled chemical technology and product development, equipment renewal and established a good cooperation and sharing relationship with many universities, In the chemical industry, we have branded (Yucai Phosphate)!