(1. 北京科技大学 土木与资源工程学院，北京 100083；
2. 北京科技大学 金属矿山高效开采与安全教育部重点实验室，北京 100083；
3. 金川集团股份有限公司 镍钴资源综合利用国家重点实验室，金昌 737100)
摘 要: 搅拌时间是保证膏体拌合物均匀的最快捷且经济的方法。本文以金川矿区粗骨料及全尾砂为主要研究对象，采用全面实验的方法研究了膏体质量浓度和搅拌时间对膏体表面状态、流动性及硬化早期强度的影响，并结合SEM扫描对不同搅拌时间条件下膏体硬化强度的发生机制进行探讨。结果表明：对应于搅拌轴不同位置的膏体振动扩散度并未呈现明显的规律性，工业搅拌机搅拌轴不同位置对膏体均质性的影响不大。随着搅拌时间增加，膏体振动扩散度越来越大，流动性逐渐得到改善。质量浓度较大时会影响膏体物料混合的均质性，对于试验中质量浓度为78%的充填物料，经过6 min的搅拌尚不足以得到密实均匀的高质量浆体。搅拌作用可以促进膏体内部结构的形成，充分的搅拌时间可以提高水泥在膏体中的分散性，C-S-H凝胶产量增大，提高膏体的硬化早期强度，结合膏体制备工艺，建议搅拌时间控制在4~5 min。
关键字: 搅拌时间；膏体均质性；流动性；早期强度；粗骨料
（1. School of Civil and Resources Engineering, University of Science and Technology Beijing, Beijing 100083, China;
2. Key Laboratory of High-Efficient Mining and Safety of Metal Mines, Ministry of Education, University of Science and Technology Beijing, Beijing 100083, China;
3. National Key Laboratory of Nickel and Cobalt Resources Comprehensive Utilization, Jinchuan Group Co., Ltd., Jinchang 737100, China）
Abstract:Mixing time is the quickest and the most economical way to ensure the homogeneity of paste mixes. In this paper, the effects of mass concentration and mixing time on the surface state, fluidity, and early hardened strength of the paste were investigated by a comprehensive experimental method using coarse aggregate and whole tailing sand from the Jinchuan mine as the main research objects. The mechanism of hardened strength of paste under different mixing time conditions was also investigated by SEM. The results show that the paste vibration diffusivity at different positions of the stirring shaft does not show obvious regularity, which has little significant effect on the homogeneity of the paste mixing at different positions of the industrial mixer. With the increase of mixing time, the vibration diffusion coefficient gradually increases, which indicates that the paste fluidity gradually improves. The mass concentration affects the homogeneity of the paste mix, and a mixing time of 6 min is not sufficient to convert a filler with a concentration of 78% into a dense and homogeneous quality paste. Mixing action can promote the formation of the internal structure of the paste, and sufficient stirring time can make the dispersion of cement in the paste increase and promote the C-S-H gel yield, thus improving the hardened strength of the paste. Combined with the paste preparation craft, the mixing time is recommended to be 4-5 min.
Key words: mixing time; homogeneity of paste; fluidity; early strength; coarse aggregate
