丁二酸对水热合成α-半水脱硫石膏微晶形貌及力学强度的影响

Effects of succinic acid on crystallite morphology and mechanical strength ofα-hemihydrate desulfurized gypsum synthesized by hydrothermal method

为提高脱硫石膏利用率和附加值,采用水热合成法在温度为95℃的15%(质量分数)氯化钠溶液中制备高强α-半水脱硫石膏材料,研究了丁二酸掺量对α-半水脱硫石膏转晶行为、物相组成、微晶形貌及力学强度的影响。结果表明,随着丁二酸掺量的增加,α-半水脱硫石膏的诱导成核与晶体生长时间均逐渐增大,转晶时间延长。同时,α-半水脱硫石膏的长径比随着丁二酸掺量的增加而降低,这有利于促进α-半水脱硫石膏水化,提高结构密实性,改善材料的力学性能。其中,掺入0.20%(质量分数)丁二酸时α-半水脱硫石膏的长径比降至1∶1左右,其2 h抗折强度和烘干抗压强度分别提高至5.54 MPa、38.47 MPa。

In order to improve untilization rate and additional value of desulfurized gypsum,high strengthα-hemihydrate desulfurization gypsum material was prepared by hydrothermal synthesis method in 15%(mass fraction)NaCl solution at 95℃.The effects of succinic acid content on crystal transformation behavior,phase composition,crystallite morphology and mechanical strength of theα-hemihydrate desulfurized gypsum were studied.The results showed that the induction nucleation and crystal growth times of theα-hemihydrate desulfurized gypsum increased gradually with the increase of mixing amount of succinic acid and the crystal transformation time was prolonged.At the same time,the length-diameter ratio of theα-hemihydrate desulfurized gypsum decreased with increase of succinic acid,which was benefit to promote hydration ofα-hemihydrate desulfurized gypsum and improve compactness to enhance mechanical properties of the materials.Among,the length-diameter ratio ofα-hemihydrate desulfurized gypsum reduced to 1∶1 with succinic acid of 0.20%(mass fraction)which enhanced the 2 h flexural strength and drying compressive strength of the materials to 5.54 MPa and 38.47 MPa,respectively.