APAM强化絮网结构后全尾砂料浆流动性能演化机制研究

There are outstanding advantages in the process of adding flocculants to accelerate the sedimentation velocity of unclassified tailings slurry, such as reduce solid-containing content of overflow water, guarantee the concentration and flow of releasing slurries, and enhance the availability of full tailings more effective and clean. This method has been widely used in mines which use filling methods at home and abroad. However, the abrasion and blocking of pipeline transportation systems occur more. The fatal reason is that flocculent structures whose structural properties are strengthened are formed by the way of flocculants combined with tailing particles. They are different from flocculent structures which are formed by charged particles attracting each other only. And then the internal structures of unclassified tailings slurries are changed, which influences macroscopic flow properties. Nevertheless, documentations show that there are few research contents about this. So, this project will use the methods by combining experimental study with theory analysis. After the flocculant of anionic polyacrylamide (APAM) is added, the characteristics of flocculent structures, the dynamic binding properties of flocculent structures with fine particle tailings, and the influence of this on hindered settling of coarse particle tailings are concentrated to be studied deeply. The change rules of flocculent structure parameters, contents of different water, vertical distribution of coarse particle tailings, and rheological parameters of full tailings slurry at different pipeline transportation situations will be studied. Accordingly, the evolution mechanism of flow properties of pipeline transportation after flocculent structures are strengthened by APAM wil be achieved. Thus, fundamental researchers are provided to solve the related pipeline transportation problems in mines.

添加絮凝剂对全尾砂浆进行快速浓密在降低溢流水含固量、保证放砂浓度和流量、提高全尾砂高效清洁利用等方面具有突出优势，在国内外使用充填采矿法的矿山中得到广泛应用，但充填管道输送系统磨损和堵管事故频发。其关键原因是絮凝剂与尾砂颗粒结合形成了结构性能加强的絮网结构，不同于仅以带电颗粒相互吸引形成的絮网结构，其改变了全尾砂料浆的内部结构，从而影响了宏观流动性能。然而，文献资料表明，该方面研究内容甚少。为此，本项目拟通过试验研究与理论分析相结合的方法，围绕添加APAM絮凝剂前后的絮网结构特征、絮网结构与细颗粒尾砂的动态结合特性，及其对粗颗粒尾砂干涉沉降的影响展开深入研究，探究不同管输情况下全尾砂料浆的絮网结构参数、水分组成、粗颗粒尾砂垂向分布及流变参数的变化规律，进而揭示APAM强化絮网结构后管道输送流动性能的演化机制，从而为解决矿山相关管道输送问题提供重要的基础理论依据。

近年来，随着矿山充填过程中全尾砂料浆质量浓度的不断提高、充填材料多样化的不断发展、各种类型外加剂的广泛使用，充填管道磨损和堵管等安全事故呈多发趋势，不仅影响了矿山的正常生产，而且造成了巨大的经济损失。为保障全尾砂料浆在充填管道内的稳定输送，项目针对APAM絮凝剂与尾砂颗粒结合强化絮网结构以后，全尾砂料浆的内部结构及宏观流动性能的变化规律及机理，展开了深入研究。基于絮凝沉降试验和料浆分层提取后激光粒度测试，确定了某铜矿残留絮凝剂的类型，统计了添加APAM前后不同质量浓度的全尾砂料浆，在不同静置时间粗颗粒的垂向分布规律，量化了全尾砂料浆在不同静置时间的结构演化特征，发现强化后的絮网结构更容易干涉粗颗粒尾砂的沉降，粗颗粒在沉降过程被这些网状结构捕获，使其在垂向分布上更加均匀；结合SEM测试，分析了细观结构的分形维数，揭示了APAM强化絮网结构机理，发现APAM高分子链上的活性基团可吸附在颗粒表面，并经过交叉、搭接等作用形成结构性能加强的絮网结构；基于静态沉降试验、动态变剪切试验和NMR测试，获得了不同静置时间未添加与添加APAM料浆的T2谱变化规律，探讨了添加APAM前后不同层位全尾砂料浆的孔隙度和水分分布特征，揭示了含残留APAM全尾砂料浆管输过程的水分迁移规律和机理，发现APAM降低了水分的活跃性，自由水迅速向更稳定水分迁移，料浆中部分游离的自由水逐渐转换为絮团水；基于恒定剪切流变试验，建立了表观黏度及切应力的相对变化值与剪切速率的函数关系，揭示了APAM对全尾砂料浆流变参数的影响规律和机理，发现APAM增大了介质黏性，吸附层减小了颗粒间的作用力，但产生了新的空间斥力位能，同时减小了颗粒下沉的空位，阻止了粗颗粒干涉沉降。研究成果为全尾砂料浆管输过程中磨损和堵管问题的解决提供了基础理论支撑。项目出版学术专著2部，发表学术论文13篇，获有中国有色金属工业科学技术奖二等奖1项。