碱激发锂渣人造骨料的制备和性能表征

Preparation and Characterization of Alkali-activated Lithium Slag-based Artificial Aggregates

锂渣是锂电池产业的重要工业废渣之一。以锂渣为原材料,利用碱激发技术制备人造骨料,并研究锂渣和激发剂用量对人造骨料性能的影响。采用颗粒强度仪测试锂渣人造骨料的单颗强度,并依照标准规范对人造骨料的其他物理性质,如成型类型、粒度分布和吸水率进行了表征与分析。使用扫描电子显微镜(SEM)研究人造骨料的微观结构,并通过X射线计算机断层扫描技术(XCT)进一步表征人造骨料内部结构。结果表明,最优配合比的骨料(LS50-6)的抗压强度可以达到5.25 MPa,并具有较高的早强性能。微观结构上,锂渣含量增加会导致骨料的致密性降低,而激发剂用量增加会导致骨料的致密性增强,且骨料的孔隙分布呈现从外到内逐渐增大的形态。这些性能使得该锂渣骨料在轻质混凝土中应用具有潜在的前景。

Lithium slag(LS)is one of waste residues in the lithium battery industry.In this paper,the LS-based artificial aggregate was designed and prepared through alkali-activated technology,during which the mix proportion of lithium slag and alkali activator was experimentally studied.The single-particle strength of LS-based artificial aggregate was measured by a particle strength meter,while the physical properties of such aggregates,such as pelleting types,particle size and water absorption,were characterized according to national standard codes.The microstructure of LS-based artificial aggregate was studied by scanning electron microscope(SEM).In particular,the internal pore structure of the aggregate was further analyzed by X-ray computed tomography(XCT).The results showed that the optimized aggregates(i.e.,LS50-6)held the compressive strength of 5.25 MPa,reaching the final compressive strength in 3 days.In terms of microstructure,the density of produced aggregate decreased with the increase of lithium slag content,but increased with the activator dosage.The internal pore distribution of the LS-based artificial aggregate sized up from the surface to the center.These properties of LS-based artificial aggregates indicated that such aggregate could be potentially used in lightweight concrete.