Mechanical Property and Leaching Rule of Improved Lithium Mica Leaching Residue Roadbed Filling Material
To study the mechanical properties of lithium mica leaching residue(lithium slag),used as roadbed filling,and reduce the leaching content of harmful substances,the cement,slag,and fly ash were used as stabilizing and solidifying materials respectively.They were added into the lithium slag in mass ratios of 2%,4%,6%,8%,and 10%to prepare the improved lithium slag specimens.The improved lithium slag strength characteristics and the harmful substances leaching rule were analyzed.The stabilization and solidification mechanism of improved lithium slag were revealed through X-ray diffraction analysis and scanning electron microscopy analysis.The result indicates that the lithium slag can react with stabilized solidification materials to form substances(e.g.,gypsum),which not only improve the lithium slag strength and compactness,but also reduce the harmful substances leaching content in lithium slag.When 4%curing material is added,the CBR values of 3 improved lithium slags increase by 35.4%,22.1%,8.5%,respectively,which can meet the requirements for roadbed filling material.With the addition of solidified materials,the unconfined compressive strength of 3 improved lithium slags can respectively reach 11.1 times,17.4 times,and 4.7 times of the initial lithium slag strength.The harmful substances leaching content in the compacted lithium slag specimens is significantly reduced,and the leaching substance content further decreases after adding solidified materials.The harmful substances leaching content of improved lithium slag increases after crushing.By adjusting the amount of solidified material,it can meet the environmental requirements for road use.The solidification effects of 3 solidification materials are ranked as follows:slag powder,cement,and fly ash.The solidification effect on manganese ions is the best,while the solidification effect on beryllium ions is similar.The solidification effect of fly ash on thallium ions is poor.
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