Portland Clinker System Containing C <sub> 4 </ Sub> A <sub> 3 </ Sub> (?) Asian Balance Of Relations And Its Microwave Secondary Synthesis Methods

To realize the concomitant of C3S and CAA3S in the quinary system of CaO-SiO2-Al2O3-Fe2O3-SO3, the paper researched the relationship of various minerals' formation at sub-equilibrium state, by which the mineral compositions optimization of clinkers, action of CaF2 during the burning and formation process of clinkers batched with steel slag had been studied. Based on these results, the paper researched the second clinkering method by microwave to burn the clinker containing C3S and C4A3S, discussed the formation progress of various mineral and analyzed the micro structure difference of clinkers burned with different methods.The result showed that, C4A3S can be formed obviously in the quinary system of CaO-SiO2-Al2O3-Fe2O3-SO3 only when the ratio of SO3/Fe2O3 is higher than 0.66. But C11A7.CaF2 would be easily formed when the ratio is too high and the formation of C3S would be also decreased. Decomposing of CAA3S in the high temperature is related to the volatilization of SO3 and the appearance of liquid in the clinker would accelerate the volatilization of SO3. To design clinker compositions with a high basicity can prevent the decomposing of C4A3S. The main mechanism of CaF2 to realize concomitant of C3S and C4A3S is that, CaF2 can improve the formation of C3S in the very low temperature. But CaF2 has no distinctly influence on C4A3S's formation or decomposing. When the content CaF2 doped in the clinker is too high, a solid solution of C3S containing F would be very easily formed.By the second clinkering with microwave, rapid burning of clinkers can be carried out and the concomitant of C3S and C4A3S can be realized. Because the burning process had been shortened remarkably, decomposing of CAA2S can be prevented. But part of CaF2 doped in the sample would not take part in the clinkers' reaction. On the other hand, impurities' amount in silicates minerals and sizes of crystals would be reduced. The configurations of C4A3S in clinkers burned with second clinkering by microwave has no obvious difference with that in clinkers burned in electric furnace, because its formation can be almost fully finished at a temperature lower than 1100℃ during the preheating of samples.When the raw meal is batched with steel-making slag, the clinkers of CaO-SiO2-Al2O3-Fe2O3-SO3 can be easily clinkered and the concomitant of C3S and CAA3S can also be realized. But when the burning temperature is too high, C3S formed in the relatively low temperature would be decomposed because RO phases in steel-making slag will absorb SiO2 to form 3F2O3.Al2O3.3SiO2 or Mg2SiO4. Increasing the designed C3S content to a suitable extent can restrain the C3S's decomposing. The test showed that it is possible to achieve the continuous clinkering with the second burning by microwave. By the equipment designed in the paper, the clinkering process of the clinker containing C4A3S can be approached. Based on the burning test, the paper proposed a basic thought to realize the fully clinkering by hybrid heating with microwave.