全尾砂-棒磨砂新型胶凝充填材料的制备

Preparation of New Backfill Cementitious Materials with Unclassified Tailings-Rod Milling Sands

将某镍矿选矿全尾砂代替部分棒磨砂作为骨料,采用正交试验和神经网络预测模型,制备以铁矿渣粉为活性材料、以脱硫灰、生石灰为主要激发剂的全尾砂-棒磨砂新型胶凝充填材料,分析了该材料的微观结构及其水化产物。结果表明:全尾砂添加质量分数为30%时,新型胶凝充填材料3 d、7 d和28 d的抗压强度分别达到1.73 MPa、4.22 MPa和6.93MPa,比水泥分别提高了8.13%、51.8%和34.0%,满足镍矿的充填强度指标。新型胶凝充填材料的主要水化产物为C-S-H凝胶,团絮状C-S-H凝胶形成结构密实的胶凝体,将骨料紧密粘结在一起形成较高的力学强度。用这种新型胶凝充填材料可实现30%的全尾砂利用率。

According to an orthogonal experimental design and neural network prediction models, a new kind of backfill cementitious materials of unclassified tailings- rod milling sands is prepared with unclassified tailings partly replaced rod milling sands as aggregates, iron slag powder as the active materials as well as desulphurized ash and quicklime as the main stimulator. Hydration products and microstructures of the backfill cementitious materials are analyzed by XRD and SEM. The results show that with addition of 30% unclassified tailings, the compressive strength of the backfill cementitious materials cured for 3 days, 7 days and 28 days reaches 1.73 MPa, 4.22 MPa and 6.93 MPa, and the corresponding increment is 8.13%, 51.8% and 34.0% respectively in comparison with the ordinary cement, and these strength values can meet the backfill strength index of Jinchuan Nickel mine. The hydration products of the new backfill cementitious materials are mainly C-S-H gel and flocculent CSH gel, which form dense gel and bond the aggregates together resulting in the high mechanical strength of the materials. Therefore, utilization of 30% unclassified tailings can be achieved for the nickel mine company through producing this new backfill cementitious materials.