Analytically pure carbonate calcium

alumina and dihydrate calcium sulfate were used to synthesize calcium sulphoaluminate(3CaO·3Al2O3·CaSO4

C4A3S) at 1375℃ for 2 h.The phase compositions and microstructure were characterized.The effects of carbon alkali concentration

alkali concentration

leaching temperature

leaching time and particle sizes on the alumina leaching properties of C4A3S were explored.The results show that the alumina leaching ratio of C4A3S increases with the increase of concentration of sodium carbonate and alkali

then trends to stable.The leaching ratio becomes higher when the particle size of clinker decreases.Compared with 12CaO·7Al2O3(C12A7)

the alumina of C4A3S is easier to be dissolved because of its porous structure

and the alumina leaching ratio is up to 98% under 10 min leaching.The concentration of sodium carbonate and the dissolution temperature of C4A3S is lower than that of C12A7.The alumina leaching ratio of C4A3S could reach 98.76% under the optimum conditions:sodium carbonate 80 g·L-1

alkali 10 g·L-1

dissolution temperature 80℃ and dissolution time 10 min.