The Effects Of Modulus,Additives And Clay Composition On The Conductivity Of Cement Raw Meal In Sintering

The quality of Portland cement clinker is related to the properties of liquid phase in sintering,and the properties of liquid phase also affects the conductance of cement raw meal in liquid phase.This paper try to establish the relationship between the liquid phase’s conductance characteristics and the quality of clinker,through explore the conductance characteristics of cement raw meal in the liquid phase by measuring the electrical impedance of cement raw meal with different formulations in the sintering process.Based on the mechanism of electrical conductivity in petrography,this project used EIS to measure the electrical impedance spectrum of cement raw meal in the range of 10～200000Hz for the high-temperature sintering process under three variables:Modulus,admixture（Na₂CO₃,Na NO₃,Mg O,Ca F₂）and clay.According to the results,two laws of electrical impedance variation of Portland cement raw meal during calcination（750～1400℃）were found:（1）The electrical impedance of cement raw meal decreases with the increase of frequency and temperature,and the decline of electrical impedance is getting smaller and smaller.（2）High frequency can makes the conductance of sample more stable,and the electrical impedance at high frequency can represent the conductance state of the system,and represent the conductance characteristics of different samples.Therefore,this paper focuses on the study of the electrical impedance in liquid phase at 200000Hz.The conclusions are as follows:（1）The electrical impedance curve at 200000Hz has two inflection points of temperature,The first inflection point represents the acceleration of the solid reactions;The second inflection point indicates that the formation of the liquid phase.Adding these admixtures will reduces inflection point’s temperature,especially Na NO₃.（2）The electrical impedance increases with the increase of Modulus,The value of KH（LSF）has the largest influence on the electrical impedance,while the value of IM（Iron Modulus）has the smallest influence.For example,at 1400℃,there are 126.2Ωincreased of electrical impedance when KH from 0.74 to 1.06;there are 65.54Ωincreased of electrical impedance when SM（Silica Modulus）from 2.00 to 2.80;there are 15.97Ωincreased of electrical impedance when IM from 1.02 to 1.67.（3）The admixture can reduce the electrical impedance in the liquid phase.And the electrical impedance of liquid phase decreases with the increase of admixture’s content,except Mg O.In fact,the continuous increase of Mg O will increase the electrical impedance slowly.Mg O has the best resistance reduction effect at the content of0.5～1.1%,it can reduce the 40.00Ωat most;Na NO₃has the best resistance reduction effect at the content of 1.1～4.0%,it can reduce the 106.01Ωat most.（4）The conductivity characteristics of sample containing different clay in the liquid phase is related to trace oxides.The more trace oxides in the clay,the more trace oxides in the cement raw meal,and the smaller electrical impedance in the liquid phase.For example,at 1400℃,N2（1.51%）has the most total content of trace oxides,and it’s electrical impedance values is 62.84Ω,lower than other samples.（5）The structure of clay minerals has very little effect on conductivity;Metal oxide and liquid phase are positively correlated with electrical impedance.The liquid viscosity is inversely proportional to the electrical impedance.（6）The lower electrical impedance of sample in the liquid phase,the larger mineral’s size of clinker and more pores of clinker.