Process ad apparatus for the manufacture of alkali metalpolyphosphates in the form of hollow spheres having a low apparent density.

摘要

Alkali metal polyphosphates consisting substantially of hollow spheroidal particles with an apparent density of less than 350 g/l are made. To this end, an alkali metal orthophosphate solution is forced under a pressure of 6-40 bars into a fluidization zone the orthophosphate solution is fluidized in the fluidization zone by injecting a finely dispersed permanent gas maintained under a pressure higher than the orthophosphate solution and the fluidized orthophosphate solution is sprayed with the aid of a plurality of single medium nozzles arranged downstream of the fluidization zone through a flame zone peoduced inside the spray tower. Apparatus for carrying out the process.