The durability of geopolymers in sulfate is essential to their application in harsh environments. In this paper, the influence of Si/Al ratio, one of the major composition parameters of metakaolin-based geopolymer (MKG), on its durability in both sodium and magnesium sulfate solutions was investigated in detail. The results indicate there is a strong coupling effect appears between Si/Al ratio and the sulfate type. The ion exchange process of MKG with different Si/Al ratios is significantly influenced by the cation of sulfate. The exchange of OH⁻ and SO₄²⁻ dominates the ion exchange process in sodium sulfate solution while the exchange of Na⁺ and Mg²⁺ dominates in magnesium sulfate solution. In addition, the variation of strength, chemical structure, micromorphology in two sulfate environments is also closely dependent on Si/Al ratio. The Si/Al ratio shows notable influence on micromorphology and strength in magnesium sulfate solution while there is negligible influence of Si/Al ratio in sodium sulfate solution.

硫酸盐中地质聚合物的耐久性对于其在恶劣环境中的应用至关重要。本文详细研究了偏高岭土基聚合物（MKG）的主要组成参数之一Si / Al比对其在硫酸钠和硫酸镁溶液中的耐久性的影响。结果表明，Si / Al比与硫酸盐类型之间存在很强的耦合作用。Si / Al比不同的MKG的离子交换过程受硫酸盐阳离子的影响很大。OH的交换^-和SO _4个^2-中硫酸钠溶液占主导地位的离子交换过程而Na交换⁺和Mg ²⁺在硫酸镁溶液中占主导地位。另外，在两种硫酸盐环境中强度，化学结构和微观形貌的变化也密切取决于Si / Al比。Si / Al比对硫酸镁溶液的微观形貌和强度有显着影响，而在硫酸钠溶液中Si / Al比的影响可忽略不计。