Properties and hydration mechanism of aluminum sulfate type alkali-free accelerator prepared from waste sulfuric acid from titanium dioxide production
DENG Lin1,2, MAO Xue-hua1
1. College of Biological and Chemical Engineering, Panzhihua University, Panzhihua 617000, China; 2. Sichuan Provincial Key Laboratory for Comprehensive Utilization of Vanadium and Titanium Resources, Panzhihua 617000, China
Abstract: 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.
邓林, 毛雪华. 工业钛白废酸制备硫酸铝型无碱速凝剂的性能及水化机理研究[J]. 现代化工, 2022, 42(11): 211-216.
DENG Lin, MAO Xue-hua. Properties and hydration mechanism of aluminum sulfate type alkali-free accelerator prepared from waste sulfuric acid from titanium dioxide production. Modern Chemical Industry, 2022, 42(11): 211-216.
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