硫酸钠对锂渣复合水泥性能的影响

Effect of sulfate on the properties of lithium slag composite cement

研究了硫酸钠对锂渣复合水泥流变性及水化性能的影响。结果表明:随着Na_(2)SO_(4)掺量增加,复合水泥浆体中AFt量增加,黏度和剪切应力升高。Na_(2)SO_(4)的掺入增加了复合水泥水化早期AFt的生成量,并使其水化放热速率曲线的第一放热峰变低变宽,第二放热峰及水化放热总量影响较小。水化初期(1 d),Na_(2)SO_(4)的掺入能促进AFt及CH的形成,为锂渣发生二次水化提供条件。在水化中后期(3、7、28 d),Na_(2)SO_(4)的掺入可破坏锂渣颗粒二次水化时包覆在其表面所形成的包覆层,同时产物NaOH提高碱度起碱激发作用,破坏锂渣中无定型结构,促进其二次水化反应,提高复合水泥密实度。

The influence of sodium sulfate on the rheological and hydration properties of lithium slag composite cement was studied.The results show that with the increase of Na_(2)SO_(4) content,the amount of AFt in composite cement slurry increases,and the viscosity and shear stress increase.The incorporation of Na_(2)SO_(4) increases the formation amount of early hydrated AFt,and makes the first exothermic peak of hydration exothermic rate curve lower and wider,and the second exothermic peak and the total amount of hydration exothermic heat have little effect.The incorporation of Na_(2)SO_(4) at the initial stage of hydration(1 d)can promote the formation of AFt and CH and provide conditions for the secondary hydration of lithium slag.The incorporation of Na_(2)SO_(4) in the middle and late hydration period(3、7、28 d)can destroy the coating layer formed on the surface of lithium slag particles during secondary hydration.Meanwhile,the product,NaOH,improves the alkalinity to act as an alkali excitation,destroys the amorphous structure in lithium slag,promotes the secondary hydration reaction and improves the compactness of composite cement.