稻壳灰的制备及其对地聚物力学性能的影响

以稻壳为原料,研究稻壳在不同酸预处理条件和不同煅烧条件下制备得到的稻壳灰在表观性能、元素成分、反应活性、物相结构和微观结构等方面的特性差异及其对偏高岭土基地聚物力学性能的影响,确定稻壳灰最佳制备条件。结果表明,盐酸预处理会显著提高稻壳灰中无定形SiO₂的纯度,高达98.354%(质量分数)。经酸预处理的稻壳在550 ℃下煅烧60 min即可煅烧完全,稻壳灰反应活性最高。酸处理后的稻壳灰使地聚物的孔隙结构更加致密,550 ℃稻壳灰地聚物(10%(质量分数)稻壳灰+90%(质量分数)偏高岭土)28 d抗压强度最高,达53.3 MPa。通过综合影响分析,得到稻壳灰的最佳制备条件为:经2.5%(质量分数)盐酸溶液浸泡1 h后,550 ℃煅烧1 h。

Preparation of Rice Husk Ash and Its Effect on Mechanical Properties of Geopolymer

Using rice husk (RH) as raw material, the differences of properties and structures of rice husk ash (RHA) prepared under different treatment conditions and the effects on the mechanical properties of metakaolin-based geopolymer were studied. The optimum preparation conditions of RHA were determined. The results show that hydrochloric acid pretreatment significantly improves the purity of amorphous SiO₂ in RHA as high as 98.354% (mass fraction). The RH pretreated by acid is calcined completely by calcining 60 min at 550 ℃ and the reaction activity of RHA is the highest. RHA treated by acid makes the pore structure of geopolymers denser and the 28 d compressive strength of 550 ℃ RHA geopolymer (10% (mass fraction) RHA+90% (mass fraction) metakaolin) is the highest, which is 53.3 MPa. Through comprehensive impact analysis, the optimum preparation conditions of RHA are as follows: immersed in 2.5% (mass fraction) hydrochloric acid for 1 h and calcined at 550 ℃ for 1 h.