原料质量配比对盐湖磷酸钾镁水泥性能和微观结构的影响

Influences of Raw Materials Mass Ratio on Properties and Microstructure of Salt Lake Magnesium Potassium Phosphate Cement

采用青海盐湖提锂副产品含硼氧化镁(B-MgO)为原料,将其适当处理后与磷酸二氢钾反应,不掺外加剂直接制备出一种盐湖磷酸钾镁水泥(Magnesium potassium phosphate cement,MKPC)。通过测试该MKPC浆体的凝结时间、水化放热温度和硬化体的抗压强度、孔隙率,分析硬化体的物相组成和微观结构形貌,研究了不同MgO/KH 2PO 4(M/K)质量配比对MKPC水化硬化过程的影响规律。结果表明:M/K质量配比对MKPC的水化放热曲线、抗压强度和孔隙率的影响显著,存在最佳M/K质量配比为1∶1~2∶1,可使MKPC在各龄期的抗压强度值均较高,3 h的最高强度值达到87.2 MPa,并使最高水化放热温度和孔隙率均保持在最佳范围;具有最佳M/K质量配比的MKPC硬化体的水化产物生成量高,晶体生长完好,缺陷少,硬化体有较完善的孔结构。

Asalt lake magnesium potassium phosphate cement(MKPC)was prepared directly by using the by-products of extracting lithium boron magnesium oxide(B-MgO)as raw material and reaction with potassium dihydrogen phosphate after appropriate treatment without admixture.The influence law of hydration hardening process of MKPC was studied by testing the setting time,hydration heat temperature,compressive strength,porosity and analyzing the phase composition and microstructure of different MgO/KH 2PO 4(M/K)mass ratio.The results indicate that M/K mass ratio has significant influence on hydration heat curve,compressive strength and porosity of MKPC.There exists an optimum M/K mass ratio of 1∶1 to 2∶1,which can make the compressive strength of MKPC higher at all curing times,the maximum strength of 3 h up to 87.2 MPa and keep the maximum hydration exothermic temperature and porosity in the optimum range.In hardened MKPC with the optimum M/K mass ratio,more hydrates are formed and grow perfectly and stably with few defects and cracks insulting in perfect microstructure.