微波焙烧活化煤矸石改善混凝土抗硫酸盐侵蚀性能的研究  

Study on microwave roasting-activated coal gangue to improve sulfate corrosion resistance of concrete

作　　者：毛诗泽 MAO Shize(Department of civil engineering,Zhengzhou College of Finance and Economics,Zhengzhou 450044,China)

机构地区：[1]郑州财经学院土木工程学院,河南郑州450044

出　　处：《无机盐工业》2025年第3期86-93,共8页Inorganic Chemicals Industry

基　　金：河南省科技攻关计划项目(HNTC2020 AB7122)。

摘　　要：高温焙烧能激发煤矸石的火山灰活性,但常规的焙烧工艺存在能耗高与耗时长的弊端。该研究采用高效节能的微波焙烧工艺提高了煤矸石的火山灰活性,研究了焙烧温度对煤矸石组成与结构的影响规律,通过对养护28 d及硫酸盐溶液侵蚀后硬化浆体的组成与结构进行表征,探究了活性煤矸石改善混凝土制品水化特性及抗硫酸盐侵蚀性能的机理。结果表明,适当提高焙烧温度可破坏煤矸石中高岭石的结构,使其转变成偏高岭石,从而赋予煤矸石凝胶活性。煤矸石经700℃焙烧后,可溶性SiO_(2)与Al_(2)O_(3)分别提升至各自总组分的40.23%与72.36%,28 d火山灰活性指数升至80.27%。活性煤矸石参与水化反应,通过消纳浆体中的Ca(OH)_(2)促进了水化硅酸钙与水化铝酸钙的生成,丰富了制品的水化产物。这不仅提高了样品的致密度与强度,而且抑制了SO_(4)^(2-)的侵蚀破坏。由于掺入700℃焙烧煤矸石的混凝土样品生成的钙矾石量最少,制品抗硫酸盐侵蚀性能最佳。然而当焙烧温度升至900℃,部分偏高岭石转变成无水化活性的莫来石,相应地制品的抗硫酸盐侵蚀性能也随之下降。High-temperature calcination can stimulate the volcanic ash activity of coal gangue,but conventional kiln calcination process was blamed for high energy consumption and long time consumption.In this study,microwave roasting technology with characteristics of efficiency and energy-saving,was applied to improve the volcanic ash activity of coal gangue,and the influence of roasting temperature on phase composition and structure of coal gangue were investigated.In the meantime,the mechanism for improving the hydration characteristics and sulfate corrosion resistance of concrete products using activated coal gangue was explored,after characterizing the phase composition and structure of the hardened slurry after 28 d of curing and sulfate solution erosion with various period.The results indicated that the structure of kaolinite in coal gangue could be destroyed,which would be subsequently transformed into metakaolinite,thus endowing coal gangue with gel activity.After calcination at 700℃,the coal gangue contained 40.23%of soluble SiO_(2)and 72.36%of soluble Al_(2)O_(3) of each.As a consequence,its 28 d volcanic ash activity index was increased to 80.27%.Activated coal gangue took part in the hydration reaction by absorbing Ca(OH)_(2)in the slurry,thus promoting the generation of hydrated calcium silicate and hydrated calcium aluminate.Consequently,the amount of hydration products was increased.It not only improved the density and strength of the sample,but also suppressed the erosion damage of SO_(4)^(2-).Because of the minimum amount of ettringite generated in the concrete sample with addition of 700℃roasted coal gangue,the product showed the best resistance to sulfate attack.However,when the calcination temperature was increased to 900℃,some metakaolin transformed into anhydrous active mullite,and correspondingly,a decrease in sulfate resistance of the product was present.

关 键 词：煤矸石 微波焙烧 火山灰活性 混凝土 抗硫酸盐侵蚀性能 

分 类 号：TQ127.2[化学工程—无机化工]