【摘要】 煤气化细渣的高效分离已成为制约其综合利用的瓶颈问题，高价金属离子对煤气化细渣的浮选回收具有明显的强化效果。以探究pH值对AlCl₃强化煤气化细渣浮选动力学及其影响机理为研究目标，采用浮选完善指标和一级浮选动力学模型分析了不同pH值下AlCl₃对煤气化细渣浮选分离效果，采用聚焦光束反射测量仪和颗粒实时录影测量系统探究不同pH值下AlCl₃对炭/灰颗粒凝聚行为的影响规律，结合DLVO理论、溶液化学计算和X射线光电子能谱分析揭示煤气化细渣中炭/灰颗粒的分散/凝聚机理。结果表明，随着矿浆pH值从3升高至9,AlCl₃处理后的煤气化细渣浮选精矿灰分保持不变，精矿产率升高，浮选完善指标逐渐升高，理论最大可燃体回收率逐渐提高。在pH值为9时，煤气化细渣中炭灰浮选速率优于其他pH值。DLVO理论计算结果表明，在AlCl₃溶液中，炭颗粒和灰颗粒各自均存在排斥作用能垒；随着矿浆pH值升高，炭颗粒保持分散状态，而灰颗粒的团聚行为愈加明显，这主要归因于碱性条件下氢氧化铝胶体对灰颗粒的化学桥联凝聚作用；另外，碱性pH值下煤气化细渣浮选产生的致密矿化泡沫较酸性pH值下大尺寸的空气泡更有利于煤气化细渣中炭颗粒的浮选回收。更多还原

【Abstract】 The efficient separation of coal gasification fine slag has become a bottleneck problem restricting its comprehensive utilization, and high-valence metal ions have a significant strengthening effect on the flotation recovery of coal gasification fine slag. The research objective is to investigate the effect of pH value on the AlCl₃ enhanced flotation kinetics and mechanism of coal gasification fine slag. The flotation perfection index and first-order flotation kinetics model were used to analyze the flotation effect of AlCl₃ on coal gasification fine slag at different pH values. A focused beam reflectance measurement system and a real-time particle visualization system were used to investigate the agglomeration behavior of carbon/ash particles induced by AlCl₃ at varying pH levels. DLVO theory, solution chemistry calculations and X-ray photoelectron spectroscopy were revealed the dispersion/agglomeration mechanism of residual carbon/ash particles. The results demonstrate that, when the ore slurry’s pH increases from 3 to 9, the ash content of the flotation concentrate remains unchanged after AlCl₃ treatment, whereas the concentrate yield, flotation performance index, and theoretical maximum recovery of combustible matter all increase progressively. At pH 9, the flotation kinetics of carbon and ash particles exhibit a superior flotation rate compared with other pH values. DLVO calculations reveal that both carbon particles and ash particles possess repulsive energy barriers in AlCl₃ solutions. As the pH increases, carbon particles remain dispersed, while the agglomeration of ash particles becomes increasingly pronounced, primarily due to chemical bridging agglomeration mediated by aluminum hydroxide colloids under alkaline conditions. In addition, the dense mineralized froths generated during the flotation of coal gasification fine slag under alkaline pH provide a more favorable environment for the flotation recovery of carbon particles than the large air bubbles formed under acidic pH.更多还原