粗磷尾矿胶结充填级配及料浆和易性规律研究

利用粗骨料进行高浓度胶结充填是矿业工程中的研究难点,也是前沿性研究课题。为高效利用粗磷尾矿以消除环境污染、土地占用以及采空区诱发的地质灾害等问题,以粗磷尾矿和粉煤灰为主要材料,首先通过SEM、ICP-MSICP-OES、XRD、激光粒度分析及其他标准测试手段对主要充填材料的物理特性、化学成分和矿物成分进行分析;然后利用Füller和Talbol最大密实度曲线理论对粗磷尾矿自然级配和不同破碎粒度磷尾矿级配进行研究;最后采用正交试验设计法及多元非线性回归法对充填料浆和易性规律进行研究。结果表明,粗磷尾矿和粉煤灰物理性能较差,但前者化学特性稳定,后者具有较强火山灰特性;-5 mm粒度破碎磷尾矿具有较优密实度;充填料浆坍落度均随胶砂比、质量浓度和水泥/粉煤灰增大而先增后减,其中胶砂比的影响程度最大;坍落扩散度均随胶砂比、水泥/粉煤灰增大而增大,随质量浓度增大而先增后减,其中质量浓度的影响程度最大;稠度均随胶砂比、质量浓度增大而减小,随水泥/粉煤灰增大而先增后减,其中质量浓度的影响程度最大,且坍落度、坍落扩散度和稠度与各因子之间存在显著非线性关系。

Research on Gradation of Coarse Phosphate Tailings Cemented Paste Backfill and Rule of Workability of Slurry

Utilization of coarse aggregate in high concentration cemented paste backfill is not only one of the main difficulties facing the mining industry, but a frontier research field. To reduce environmental pollution, land occupation and geological disaster caused by coarse phosphate tailings and voids, coarse phosphate tailings and fly ash were used for the main backfill materials. Firstly, physical, chemical and mineralogical properties of phosphate tailings and fly ash were tested by SEM, ICP-MS ICP-OES, XRD, Laser Particle Analyzer and other standard testing methods. Secondly, the gradation of coarse phosphate tailings and crushed phosphate tailings with different particle size were studied by Füller and Talbol theories. Finally, the rule of unconfined compressive strength of cemented backfill was studied by orthogonal experimental design and multiple nonlinear regression. The results show that the physical properties of coarse phosphate tailings and fly ash are both poor, however the coarse phosphate tailings have stable chemical properties and the fly ash has high pozzolanic properties. The crushed phosphate tailings with -5mm can be used as the aggregate for the pipeline-conveying paste backfill due to its high compactness. The slump of slurry increases first and then decreases with the increase of cement-aggregate ratio(CA), concentration(C) and cement to fly ash ratio(CF), and CA effects the most; the slump flow increases with the increase of CA and CF, increases first and then decreases with the increase of C, and C effects the most; the consistency decreases with the increase of CA and C, increases first and then decreases with the increase of CF, and C effects the most. Furthermore, the workability of the slurry has significant nonlinear relationship with CA, C and CF.