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黏土为天然微纳米材料,但团聚体存在形式限制了其微纳米特性在其应用领域有效发挥。以扫描电子显微镜(SEM)和粒度分布检测为主要表征手段,考察了基于蒸汽爆破处理的凹凸棒石黏土微纳米化及晶束解离的可行性。实验发现:挤压预处理可以显著增强黏土的溶剂化作用程度,提升微纳米化效率;适度的重复爆破处理在保证凹凸棒石高长径比形貌特征基础上晶束解离充分;蒸汽爆破所得样品为高度蓬松粉体,棒晶纤维的长径比保持良好,晶束直径普遍小于200 nm(约为2~5根凹凸棒石棒晶组成)。理论分析及实验结果均表明:本工艺下的爆破处理是解离作用而不是常规粉碎下的脆性断裂;深入凹凸棒石黏土颗粒内部各级孔隙结构且能瞬间气化释放的分散介质是解离凹凸棒石黏土的有效介质。
Clay is a natural micro-nano material, but the existence of aggregates limits the effective use of its micro-nano properties in its fields of application. Scanning electron microscopy (SEM) and particle size distribution detection were used as the main characterization methods to investigate the feasibility of micro-nanocrystallization and dislocation of attapulgite clay based on steam explosion. The experimental results show that extrusion pre-treatment can significantly enhance the degree of solvation of clay and improve the efficiency of micro-nano-milling. The moderate repeated blasting can fully dissociate the crystal beam on the basis of the feature of high aspect ratio of attapulgite. The resulting sample was a highly fluffy powder. The aspect ratio of the rod-like fibers remained well and the diameter of the beam was generally less than 200 nm (about 2 to 5 attapulgite rods). Theoretical analysis and experimental results show that: the blasting process under this process is a dissociation rather than a brittle fracture under conventional comminution; the dispersion medium that is deeply released into the pore structure at all levels of attapulgite clay particles and can be instantaneously vaporized is dissociated Effective medium for attapulgite clay.