以提高氯离子固化效果为出发点，开展了改性水滑石及碳铝酸钙对脱硫石膏中氯离子固化作用的研究。结果表明，二者对脱硫石膏中氯离子均有明显的固化作用，且脱硫石膏中氯离子随固化剂掺量增大均呈先降后升趋势。当改性水滑石和碳铝酸盐掺量分别为5%和20%时，脱硫石膏中氯离子量达到最低，且均低于400ppm，这满足了石膏制品对氯离子含量要求。由于改性水滑石拥有较大层间空位结构，且其对氯离子的吸附力超过硫酸根离子，故改性水滑石可实现在硫酸根溶液中对氯离子的吸附作用，同时因该吸附为动态平衡吸附过程，故存在最佳掺量。而碳铝酸钙属于X-AFm体系，氯离子和碳酸根均可作为X。依照X优先进入AFm层间顺序，氯离子可取代碳酸根进入AFm层间，从而实现其对氯离子的固化作用。

To improve the solidification effect of chloride ions in FGD gypsum, the solidification of modified hydrotalcite and calcium carboaluminate on chloride ions in desulfurization gypsum is studied. The results show that both solidifying agents have a significant solidification effect on the chloride ions in FGD gypsum, and the content of chloride ions firstly decreased and then increased with the amount of solidifying agents used. When the dosage of modified hydrotalcite and calcium carboaluminate is 5% and 20% respectively, the content of chloride ions in FGD gypsum is the lowest, which is below 400 ppm and meets the requirements for chloride ion content in gypsum products. There is a large interlayer structure space in modified hydrotalcite, whose adsorption capacity for chloride ions exceeded for sulfate ions, so modified hydrotalcite can achieve the adsorption of chloride ions in sulfate solution. At the same time, because the adsorption belongs to a dynamic equilibrium process, there is an optimal dosage for modified hydrotalcite. Calcium carboaluminate belongs to the X-AFm system, and both chloride ions and carbonate ions can serve as X. According to the priority order of X entering the AFm interlayer, chloride ions can replace carbonate ions to enter the AFm interlayer and achieve solidification effect on chloride ions.

TQ177.3; X701.3

中国建材集团攻关专项（2021HX2223）