Hydration dynamic process and hydration mechanism of alkali excited flotation tailings filling material

FAN Yuping; LI Dehao; DONG Xianshu; MA Xiaomin; FU Yuanpeng

doi:10.13247/j.cnki.jcumt.20220523

Abstract：Flotation tailings coal was used to replace some cement-prepared cementitious mate-rials to study the variation characteristics of volcanic ash properties and hydration kinetics process,aiming to achieve a better balance between the cost and performance of cementitious materials in filling materials,The activity rate Ka was employed to characterize the volcanic ash activity of cementitious materials,the hydration exothermic rate of cementitious materials was determined by TAM Air isothermal calorimater,and the hydration kinetic parameters of tailings coal cementitious materials were calculated based on the Krstulovic-Dabic hydration ki-netic model.The results show that the best condition for the activity excitation of volcanic ash of flotation tailings coal is to add solid sodium silicate activator with mass fraction w(sodium silicate)=6％after calcination at 800 ° C for 3 h,and the highest activity rate Ka is 18.85％.Compared with cement cementitious materials,the second peak of the hydration exothermic characteristic curve of flotation tailings coal cementitious materials decreases significantly and moves forward,showing lower hydration exothermic rate and hydration heat release.Through the analysis of the variation characteristics of hydration kinetics process,it is found that the transition nodes from NG process to Ⅰ process and from Ⅰ process to D process of the flotation tailings coal cementitious materials move forward.Therefore,a descriptive model of hydration kinetic process of tailings coal cementitious material is established.The cementitious materials prepared by the combined treatment of thermal activation and alkali excitation show faster hy-dration rate and lower heat release,which can effectively reduce the cost of filling materials when applied to filling mining.