采用工业钛白废酸和氢氟酸酸解氢氧化铝，合成了含氟硫酸铝型无碱速凝剂。考察了不同掺量下含氟无碱速凝剂对水泥浆料性能的改变，同时通过XRD和SEM分析了加入速凝剂后水泥水化产物的组成和微观结构；提出水化概念模型，模拟含氟无碱速凝剂水化反应机理。结果表明，钛白废酸结合氢氟酸能更好地溶解氢氧化铝，且加入氢氟酸有利于提高速凝剂中铝元素的含量，使得含氟速凝剂质量分数最高可达48%，性能更佳；在7%含氟速凝剂掺量下，水泥基体初凝时间和终凝时间分别为3.17 min和5.33 min，所制备的无碱速凝剂符合GB/T 35159—2017《喷射混凝土用速凝剂》中合格品的要求。该技术为废硫酸重复再利用提供了一种参考方式。

Aluminum sulfate type fluorine-containing alkali-free accelerators are prepared by acid hydrolysis of Al(OH)₃ with hydrofluoric acid and waste sulfuric acid from titanium dioxide production.The effect of different dosages of fluorine-containing alkali-free accelerator on the performance of cement paste is investigated.The composition and microstructure of cement hydration products after adding accelerator are analyzed by means of XRD and SEM.The hydration conceptual model is proposed to simulate the hydration reaction mechanism of fluorine-containing alkali-free accelerator.Results show that waste sulfuric acid combined with hydrofluoric acid can dissolve aluminum hydroxide better,and the addition of hydrofluoric acid is beneficial to increase the content of aluminum in accelerator,making the performance of the accelerator better,and the maximum mass fraction can reach 48%.The initial setting time and final setting time of cement matrix are 3.17 min and 5.33 min,respectively when the dosage of fluorine-containing alkali-free accelerator is 7%.The prepared fluorine-containing alkali-free accelerator meets the requirements of qualified products in GB/T 35159—2017 Flash Setting Admixtures for Shotcrete.The preparation technology provides a treatment method for the reuse of waste sulfuric acid.