Experimental Study On The Formation Rules Of Q Phase-Calcium Sulphoaluminate Cement Clinker

While coal-fired power industry provides our society with clean electric power,the generation of jillion fly ash confronts us with pressure from deterioration of environment.Study on comprehensive utilization and realization of resource,reduction and benefit of fly ash become ways and means of mitigation of environment pressure and shortage of nature resource.The innovation of the experimental study in this paper,lie in achievement of source utilization of fly ash,realization of circular economy between coal-fired power industry and cement industry.This paper carried out the pure fly ash and analysis combined with the preparation of Q phase key techniques of ecological cement.First,Using pure according to the analysis of the generation of the chemical equation of raw meal proportioning design calculation,and under the condition of 1350 ℃ high temperature calcination in order to explore Q phase-calcium sulphoaluminate cement clinker formation.By adjusting the analytical pure Ca O,analytical pure MgO and analytical pure CaSO₄ mix to explore its effect on the clinker formation.The results show that with the increase of Ca O adding quantity,objective product of Q phase diffraction intensity first increases then decreases and then continue to increase.With the increase of MgO adding quantity,objective product of Q phase diffraction intensity first increases then decreases and then continue to increase,and when the MgO additives reaches a certain amount,the2CaO·MgO·2SiO₂ occur,causing a sharp drop in production of Q phase.Using analysis of pure according to calcium sulphoaluminate clinker mineral generates formula for making the process of the clinker minerals,with the increase of Ca O additives,target product3CaO·3Al₂O₃·CaSO₄ diffraction intensity gradually increased,and the trend of strengthen is gradually slow.With the increase of CaSO₄ additives,target product 3CaO·3Al₂O₃·CaSO₄ showed a trend of slow increase of diffraction intensity,and when the CaSO₄ additives to a certain degree,the diffraction intensity does not continue to increase.In the process of preparing Q phase-calcium sulphoaluminate clinker mineral,the clinker mineral of3CaO·3Al₂O₃·CaSO₄ has more competitive advantage for Ca O.It’s a matter about mineral generate equations of activation energy.With the increase of CaO additives,3CaO·3Al₂O₃·CaSO₄ diffraction intensity first increases then decreases and then continue toincrease,and Q phase occurs when the generate of 3CaO·3Al₂O₃·CaSO₄ is complete.The content of 3CaO·3Al₂O₃·CaSO₄ is dominate in the clinker mineral composition.Testing the raw material for chemical composition of fly ash,from the chemical composition analysis of fly ash,we can clearly see,the chemical composition of fly ash is similar to the clayey materials used in the cement production,the content of Si and Al is high.It is entirely possible to use fly ash in place of the clayey material in the cement industry.Explore the forming rules of Q phase and calcium sulphoaluminate,and the competitive relation between Q phase and calcium sulphoaluminate.Fly ash,analytical pure MgO,analytical pure Ca O and analytical Si O2 were selected as experimental materials.According to the molecular formula of the major minerals of the mineral composition of the Q phase cement（6CaO·4Al2O3·MgO·SiO2）,the proportional programme of raw material of the Q phase cement were designed and calculated.There are three designed proportional programme in this paper:（1）Fly ash,analytical pure MgO,analytical pure Ca O were selected as experimental materials,the fundamental proportional programme of the Q phase cement raw material was designed.（2）Analytical pure MgO,analytical pure Al2O3,analytical pure Ca O and analytical pure Si O2 were selected as experimental materials,according to the fundamental proportional programme of Q phase cement raw material,the proportional programme of raw material of the Q phase by analytical pure was designed.（3）Analytical pure Al2O3,analytical pure CaSO₄,analytical pure Ca O and analytical pure Si O2 were selected as experimental materials,according to the fundamental proportional programme of calcium sulphoaluminate（3CaO·3Al₂O₃·CaSO₄）cement raw material,the proportional programme of raw material of calcium sulphoaluminate by analytical pure was designed.Second,Preparation of raw materials by using fly ash,analytical pure MgO,analytical pure Ca O,in nine different analytical pure mixing ration,in the condition of 1350 degrees temperature calcination.With adjustments of addtives content in agglomeration coal powder,minerals component of coproduction modified fly ash varied from mainly consisting of no-active minerals gradually to appearance of trifling cement clinker minerals,to appearance of cement clinker and aim mineral of Q phase.Experiments results testified the feasibility of coproduction of Q phase cement clinker from fly ash and analytical pure.In order to ascertain formation mechanism of Q phase in the process of cement clinker,experiments of influencing factors such as calcinations temperature and pulverized coal different sieve mesh were performed in this paper.The results showed that under the condition of 5 groups of different calcination temperature,set at each temperature insulation calcined for 30 minutes,the target Q phase in the clinker minerals when the calcinationtemperature is 1330 ℃.The result is consistent with Q phase formation temperature1300¹350℃ temperature range,and the generated of Q phase increases slow after 1330℃.Smaller the granularity of pulverized coal and analytical pure,the react of analytical pure with pulverized coal are more easier in the process of calcination,generate the target minerals Q phase.The target minerals will occur when pulverized coal mesh for more than180 mesh.Through thermodynamic calculation and analysis,the direct synthesis reaction of 2CaO·Al₂O₃·SiO₂ are priority,the direct synthesis reaction of 2CaO·SiO₂ are followed,next is the indirect synthesis reaction of Q phase,the last is the indirect synthesis reaction of 3CaO·3Al₂O₃·CaSO₄.The analysis results are consistent with experimental results.