Use of fluidized bed combustion ash as raw feed in the manufacture of calcium sulfoaluminate cements

.Both utilization and disposal of fluidized bed combustion (FBQ waste are complicated by its chemical and mineralogical composition. It has a quite high content of CaO and CaSO4 responsible for exothermal and expansive phenomena upon hydration; furthermore, due to the low combustion temperature, it contains a coal ash having a limited amount of glass phase and therefore a poor pozzolanic activity. In this paper, the suitability of FBC waste as raw feed component for the manufacture of calcium sulfoaluminate cements is assessed, which can be utilized for a wide range of applications. Mixtures containing FBC wastes derived from both laboratory and industrial plants were synthesized into an electric oven in the temperature range 1000°-1300°C. De-pending on the proportioning of the constituents of the raw feed as well as on the synthesis conditions, burning products having as main components the desired hydraulic phases were obtained.