【作者】 刘斌；

【导师】 于广锁； 吕鹏；

【作者基本信息】 宁夏大学 ， 化学工程与技术， 2025， 博士

【摘要】 煤气化是煤炭清洁高效利用的关键技术和重要途径。气化细渣是煤气化过程中产生的固体废弃物,其年产量大、综合利用率低,大量堆存不仅占用土地资源,还对区域生态环境造成显著负面影响。气化细渣在资源化利用方面既展现出重要的理论价值,又面临着显著的技术挑战,这已成为制约煤气化技术实现高效低碳发展的关键瓶颈因素。本文以气流床煤气化细渣为研究对象,进行碳/灰浮选分离机制及分级制备功能化多孔材料对废水吸附机理研究。通过分析气化细渣物理化学特性解析残碳与矿物质赋存模式及形成机制;基于不同粒级气化细渣的浮选行为及细颗粒对浮选效率的影响,揭示浮选过程中粒度效应及颗粒的聚集与分散行为;基于浮选分离的富灰/富碳组分制备功能化多孔材料,通过吸附动力学、吸附热力学及吸附等温线研究其对印染废水中重金属离子和染料分子的去除性能,重点揭示重金属离子与染料分子的协同去除机制;在此基础上,研究气化细渣基活性炭在不同温度下对重金属离子的吸附机理和竞争吸附效应,基于统计物理吸附模型从分子水平阐明吸附过程中能量变化规律与离子结合机制。为气化细渣的资源化利用提供理论依据和技术支持。主要内容如下:（1）基于气化细渣理化特性与粒度组成的显著相关性,研究不同粒级气化细渣的理化特性、碳灰赋存模式及形成机制。结果表明,气化细渣颗粒具有狭缝状孔隙结构,其中>180μm颗粒石墨化程度最低,中间粒度颗粒残碳含量最高,<45μm颗粒表面粗糙度最小。气化细渣中残碳和矿物质呈现嵌入分布、交联分布及离散分布三种赋存模式。原煤颗粒在气化炉内的反应历程可分为初始、过渡及后期三个阶段,由于反应历程差异,三种碳灰赋存模式并非独立存在,而是以多种模式相互交织、复合共存的形式呈现。（2）粒度特征是影响气化细渣中残碳与矿物质分离效率的关键因素。通过实验与理论计算相结合的方法,分析<45μm、45–180μm和>180μm三个粒级气化细渣的浮选行为与分离效果。气化细渣颗粒表面呈弱疏水性,浮选试剂能够显著改善其疏水性。随着粒度减小,浮选回收率逐渐降低,其中<45μm细颗粒对浮选效果的负面影响尤为显著。浮选过程中,细颗粒存在选择性差和回收率低的问题,主要归因于其重力小、动能低,难以克服气泡表面水化层阻力,导致非选择性附着。理论计算表明,随着粒径增大,颗粒间的总相互作用能显著提高,从而改善了浮选效率。（3）基于气化细渣基富灰组分,通过简单酸浸和多步改性制备功能化多孔二氧化硅,研究其在单一和二元废水体系中对Pb²⁺和刚果红染料的吸附行为。结果表明,功能化多孔二氧化硅表面富含含氮/含氧官能团,在单一废水体系中对Pb²⁺和刚果红的最大吸附量分别为302.39 mg/g和342.74 mg/g;在二元吸附体系中,吸附量分别提升至372.73 mg/g和412.93 mg/g。吸附量的增加源于静电吸引和配位螯合的协同效应。吸附动力学表明,对Pb²⁺的吸附符合拟二级动力学模型,表现为单层吸附;对刚果红的吸附符合Elovich动力学模型,表现为多层吸附。（4）基于气化细渣基富碳组分制备氨基功能化活性炭,研究其对重金属离子的吸附行为及竞争吸附效应,并通过统计物理模型从分子水平对吸附过程进行微观解释。结果表明,功能化活性炭对Cd²⁺和Pb²⁺表现出优异的吸附性能,Pb²⁺的吸附为自发过程,Cd²⁺的吸附为非自发过程。吸附过程以化学吸附（螯合作用与共价键作用）为主。统计物理模型分析表明,单一吸附体系为多分子吸附过程,二元吸附体系则为多锚定吸附过程。吸附能力主要取决于受体位点上的离子数量及吸附剂受体位点密度,环境温度的升高会加剧重金属离子在吸附剂孔隙中的热运动,同时会削弱在活性位点上的聚集能力。更多还原

【Abstract】 Coal gasification is a pivotal technology and an essential means for the clean and efficient utilization of coal.Coal gasification fine slag（CGFS）is a solid waste produced during the coal gasification process,which has a large quantity annually and low comprehensive utilization.A large amount of CGFS not only occupies land resources but also causes significant negative impacts on the regional ecological environment.The unique physicochemical properties of CGFS provide a theoretical foundation for its resource utilization.However,these properties also increase the complexity of its utilization,presenting a major challenge to achieving high-efficiency and low-carbon operation in the coal gasification industry.This thesis focuses on CGFS as the research subject,investigating the flotation separation mechanism of residual carbon/minerals,as well as the adsorption mechanism of wastewater by functionalized porous materials prepared.Through comprehensive characterization of the physicochemical properties of CGFS,the residual carbon and the minerals distribution modes and formation mechanisms are elucidated.The flotation behavior of different particle sizes CGFS is examined,along with the impact of fine particles on flotation efficiency.Reveals the effects of particle size,as well as the aggregation and dispersion behavior of particles during flotation.Based on the flotation separation of enrichment-ash and enrichment-carbon components of the CGFS,functionalized porous materials are then prepared.The preparation of these materials is guided by the kinetics,thermodynamics and isotropic adsorption behaviors,which are studied through adsorption kinetics,thermodynamics,and isotherms to assess their performance in removing heavy metal ions and dye molecules from printing and dyeing wastewater.The research focuses on uncovering the synergistic removal mechanism of heavy metal ions and dye molecules.Furthermore,the adsorption mechanism and the competitive adsorption effect of CGFS-based activated carbon on heavy metal ions at various temperatures are analyzed.The study delves into the ion-binding mechanisms and energy changes during the adsorption process at the molecular level,employing a statistical physicochemical adsorption model.This model helps explain the energy dynamics and ion interactions during adsorption.The research aims to provide a theoretical basis and technical support for the resource utilization of CGFS.The main research contents and conclusions are as follows:（1）Based on the significant correlation between the physicochemical properties and particle size composition of CGFS,the study investigates the physicochemical properties,distribution modes and formation mechanisms of different sizes CGFS.The results showed that the CGFS have slit-like pore structures,with particles larger than 180μm having the lowest degree of graphitization,particles in the range of intermediate grain size having the highest residual carbon content and particles smaller than 45μm having the smoothest surface.The residual carbon and minerals in CGFS exhibit three distribution modes:embedded distribution,crosslinked distribution and discrete distribution.The reaction process of coal particles in the gasifier can be divided into three stages:initial,transitional and final stages.Due to the differences in the reaction process,these three distribution modes do not exist independently but are interwoven and coexisting in multiple modes.（2）Particle size characteristics are key factors affecting the separation efficiency of residual carbon and minerals in CGFS.Using a combination of experiments and theoretical calculations,the flotation behavior and separation effects of CGFS with three particle sizes（<45μm,45–180μm and>180μm）were systematically analyzed.The CGFS particles exhibit weak hydrophobicity and flotation reagents significantly improve their hydrophobicity.As particle size decreases,flotation recovery gradually decreases,with the negative impact of fine particles CGFS（<45μm）on flotation efficiency being particularly significant.Fine particles suffer from poor selectivity and low recovery rates,primarily due to their small gravity,low kinetic energy and difficulty in overcoming the hydration layer resistance on the surface of the bubbles,leading to non-selective attachment.Theoretical calculations indicate that as particle size increases,the total interaction energy between particles significantly increases,thereby improving flotation efficiency.（3）Functionalized porous silica was prepared through simple acid leaching and multi-step modification based on the enrichment-ash component of CGFS.The adsorption behavior of this material for Pb²⁺and Congo red dye in single and binary wastewater systems was studied.The results showed that the surface of functionalized porous silica is rich in nitrogen/oxygen-containing functional groups and the maximum adsorption capacities for Pb²⁺and Congo red in the single wastewater system are 302.39mg/g and 342.74 mg/g,respectively.In the binary adsorption system,the adsorption capacities increase to 372.73 mg/g and 412.93 mg/g,respectively.The increase in adsorption capacity is attributed to the synergistic effect of electrostatic attraction and coordination chelation.Adsorption kinetics indicate that the adsorption of Pb²⁺follows the pseudo-second-order kinetic model,demonstrating monolayer adsorption,while Congo red adsorption follows the Elovich model,indicating multilayer adsorption.（4）Amine-functionalized activated carbon was prepared based on the enrichment-carbon component of CGFS,its adsorption behavior for heavy metal ions and competitive adsorption effects were studied.The results showed that the adsorption process was microscopically explained at the molecular level using statistical physics models.The functionalized activated carbon exhibits excellent adsorption performance for Cd²⁺and Pb²⁺.The adsorption of Pb²⁺is a spontaneous process,while that of Cd²⁺is a non-spontaneous process.The adsorption process is dominated by chemical adsorption（chelating and covalent bond formation）.Statistical physics model analysis indicates that the single adsorption system involves a multi-molecule adsorption process,while the binary adsorption system involves multi-anchor adsorption.The adsorption capacity primarily depends on the number of ions at the receptor sites and the receptor site density of the adsorbent,with higher environmental temperatures exacerbating the thermal motion of heavy metal ions in the pores of the adsorbent,while weakening the aggregation ability at active sites.更多还原