【作者】 杨虹；

【导师】 王海龙；

【作者基本信息】 内蒙古农业大学 ， 水工结构工程， 2025， 博士

【摘要】 随着全球经济的快速发展,能源短缺问题日益凸显。中国作为世界主要能源消费国,其能源结构呈现"富煤、贫油、少气"的特征,煤炭占比超过70%,这一格局短期内难以改变。然而,传统煤炭利用方式存在转化效率低、环境污染严重等问题。在此背景下,煤炭的清洁高效转化成为实现能源低碳发展的关键。煤气化技术作为洁净煤利用的核心技术,具有高效、经济、环保等优势,是煤基化学合成、液体燃料合成等工业的工艺基础。但煤气化过程产生的煤气化渣（CGS）带来了新的环境挑战,其年产量达数千万吨,目前主要采用堆贮和填埋方式处理,不仅造成土地资源浪费,还存在环境污染风险。针对这一问题,本研究聚焦于脱碳煤气化渣的资源化利用,通过碱激发与盐碱协同技术制备胶凝材料,系统研究了其物理化学特性、活化机制及工程应用性能,为实现煤气化渣的高效利用和煤化工行业的可持续发展提供了新的解决方案。主要研究成果如下:（1）揭示了碱-硫酸盐协同激发硅铝溶出机制,阐明了Ca²⁺吸附调控表面电位机理。脱碳煤气化渣主要化学组成为Si O₂和Al₂O₃,结晶相以石英和灰钙硅石为主,同时含有高比例玻璃体相,表现出高化学活性,适合作为碱激发胶凝材料前驱体。溶出行为研究表明,Si和Al在Na OH溶液中的溶出效率显著高于其他溶液体系,分别在5 mol/L和9 mol/L碱浓度下达到峰值,且碱-硫酸盐复合体系中Na₂SO₄显著增强了Si和Al的溶出效率,表明碱与硫酸盐存在协同效应。表面化学特性分析显示,脱碳煤气化渣粉体表面电位随p H升高而下降,Ca²⁺浓度显著影响Zeta电位,Ca²⁺在颗粒表面的特异性吸附行为导致其在Ca（OH）₂溶液中的电位高于Na OH体系。研究结果为优化激发剂体系及脱碳煤气化渣的资源化利用提供了重要理论依据。（2）揭示了气化渣掺量对水泥浆体性能的阈值效应,阐明了其火山灰活性差异驱动水化产物相变与孔隙劣化机制。气化渣在水化早期表现出低火山灰活性和粗糙多孔特性,导致随其掺量增加,水泥浆体凝结时间延长、流动度降低,但气化渣含量不超过60%时仍满足凝结要求。抗压强度随气化渣掺量增加而下降,其中掺量低于30%时,28天抗压强度仅下降9.3%,水化产物以Ca（OH）₂和C-S-H凝胶为主;掺量超过30%后,强度显著下降（如C-60%下降36.4%）,水化产物以C-A-S-H凝胶为主。气化渣的高比表面积和吸水特性导致浆体孔隙率增加、微观结构致密性降低。尽管如此,气化渣掺量低于30%时,水泥浆体仍表现出较高的抗压强度、致密的微观结构和良好的工作性能,表明气化渣是一种优质的辅助胶凝材料（SCMs）。（3）开发了脱碳煤气化渣-电石渣-脱硫石膏三元复合胶凝材料,揭示了碱性-硫酸盐协同激发硅铝活化及钙矾石填充强化的多尺度增强机制。脱碳煤气化渣、电石渣和脱硫石膏在水化过程中表现出显著的协同效应,三元体系的力学性能最优,其抗压强度显著高于二元体系和单一体系。电石渣提供的碱性环境和脱硫石膏引入的硫酸盐共同促进了脱碳煤气化渣中硅铝组分的活化,显著增加了C-S-H凝胶、C-（A）-S-H凝胶及针状钙矾石的生成量。钙矾石通过形成加筋结构、连接裂缝及填充孔隙等机制,进一步增强了材料的致密性和完整性。TG、FTIR和SEM分析证实了复合协同效应的化学基础,表明三元体系胶凝材料具有优异的力学性能和微观结构。（4）探明了矿渣与硫酸钠协同触发溶出-凝胶化过程及钙矾石成核-填充效应机制,明确了硫酸钠掺量阈值对膨胀裂纹的约束关系。矿渣的掺入促进了C-S-H和C-A-S-H凝胶的生成,优化了微观结构,而适量Na₂SO₄（10%）的引入进一步通过协同作用促进了C/N-A-S-H凝胶和钙矾石（AFt）的形成,显著提高了材料的早期和后期抗压强度（3 d和28 d分别达到17.45 MPa和30.29 MPa）。然而,过量Na₂SO₄（>10%）会导致钙矾石过量生成,引发体积膨胀和微裂纹,从而降低材料性能。XRD、TG、FTIR、SEM和MIP分析表明,矿渣和Na₂SO₄的协同作用显著增强了硅铝物质的溶出和凝胶相的形成,优化了孔结构并提高了基体密实度。因此,适量矿渣和Na₂SO₄的掺入可显著改善胶凝材料的力学性能和微观结构,但需严格控制Na₂SO₄掺量以避免不利影响。（5）开发了工业副产渣基环保砂浆,揭示了底泥掺量对材料性能的影响规律,实现了固废资源化与低碳制备协同增效,兼顾力学性能和环保效益。随着底泥取代率的增加（0%～100%）,砂浆流动度显著下降（降幅超过43%）,抗压强度和抗折强度呈现阶段性降低趋势,其中底泥掺量控制在50%以内时,环保砂浆28天抗压强度可达25.8 MPa,满足M 20砂浆要求。底泥的高比表面积、强吸水特性及惰性特性导致水化产物减少、孔隙率增加及微观结构疏松化,但合理控制底泥掺量可优化孔结构并维持砂浆的力学性能。此外,采用工业副产物制备的环保砂浆碳排放总量仅为42.6kg CO₂/m³,较普通砂浆（506.2 kg CO₂/m³）显著降低,表明该环保砂浆在保证力学性能的同时,具有显著的固废资源化利用潜力和环保效益。更多还原

【Abstract】 With the rapid development of the global economy,the problem of energy shortage has become increasingly prominent.China,as one of the world’s major energy-consuming countries,has an energy structure characterized by"abundant coal,scarce oil,and limited natural gas,"with coal accounting for as high as 94%.This pattern is difficult to change in the short term.However,traditional coal utilization methods suffer from low conversion efficiency and severe environmental pollution.Against this backdrop,the clean and efficient conversion of coal has become the key to achieving low-carbon energy development.Gasification technology is a core technology for clean coal utilization,featuring high efficiency,economy,and environmental protection.It serves as the basis for industrial processes such as coal-based chemical synthesis and liquid fuel synthesis.However,the gasification process generates gasification slag（CGS）,which poses new environmental challenges.With an annual output of tens of millions of tons,CGS is currently mainly treated by stockpiling and landfilling.These methods not only waste land resources but also pose risks of environmental pollution.In response to this issue,this study focuses on the resource utilization of decarbonized gasification slag.By using alkali activation and the combined alkali-salt technology to prepare cementitious materials,the study systematically investigates the physicochemical properties,activation mechanisms,and engineering application performance of these materials.This research provides a new solution for the efficient utilization of gasification slag and the sustainable development of the coal chemical industry.The main research results are as follows:（1）The mechanism of synergistic activation of silicate and aluminate dissolution by alkali-sulfate was revealed,and the mechanism of surface potential regulation by Ca²⁺adsorption was clarified.The main chemical components of decarbonized gasification slag are Si O₂ and Al₂O₃,with crystalline phases primarily consisting of quartz and gehlenite.It also contains a high proportion of glassy phase,which exhibits high chemical reactivity,making it suitable as a precursor for alkali-activated binders.Leaching behavior studies have shown that the leaching efficiency of Si and Al in Na OH solution is significantly higher than in other solution systems,reaching peak values at alkali concentrations of 5 mol/L and 9mol/L,respectively.In the alkali-sulfate composite system,Na₂SO₄ significantly enhances the leaching efficiency of Si and Al,indicating a synergistic effect between alkali and sulfate.Surface chemical property analysis indicates that the zeta potential of decarbonized gasification slag powder decreases with increasing p H.The concentration of Ca²⁺significantly affects the zeta potential,and the specific adsorption behavior of Ca²⁺on the particle surface results in a higher zeta potential in Ca（OH）₂ solution compared to the Na OH system.The research findings provide an important theoretical basis for optimizing the activator system and the resource utilization of decarbonized gasification slag.（2）The threshold effect of gasification slag content on the properties of cement paste was revealed,and the mechanism of pozzolanic activity differences driving hydration product phase transformation and pore deterioration was clarified.The gasification slag exhibits low pozzolanic activity and rough porous characteristics in the early stages of hydration.As its content increases,the setting time of the cement paste is prolonged and its flowability decreases.However,when the content of gasification slag does not exceed 60%,the paste still meets the setting requirements.The compressive strength decreases with increasing gasification slag content.When the content is below 30%,the 28-day compressive strength only decreases by 9.3%,with hydration products mainly consisting of Ca（OH）₂ and C-S-H gel.When the content exceeds 30%,the strength drops significantly（e.g.,a 36.4%decrease at 60%content）,and the hydration products are dominated by C-A-S-H gel.The high specific surface area and water absorption properties of gasification slag leaded to increased porosity and reduced microstructural density of the paste.Despite this,when the gasification slag content is below 30%,the cement paste still exhibits high compressive strength,a dense microstructure,and good workability,indicating that gasification slag is a high-quality supplementary cementitious materials（SCMs）.（3）A ternary composite cementitious material composed of decarbonized gasification slag,carbide slag,and desulfurization gypsum was developed.The multi-scale strengthening mechanisms driven by alkaline-sulfate synergistic activation of silicate and aluminate,as well as ettringite filling reinforcement,were revealed.The decarbonized gasification slag,calcium carbide slag,and flue gas desulfurization gypsum exhibit a significant synergistic effect during hydration.The ternary system has the best mechanical properties,with compressive strength significantly higher than that of the binary and single systems.The alkaline environment provided by calcium carbide slag and the sulfate introduced by flue gas desulfurization gypsum jointly promote the activation of silicon and aluminum components in decarbonized gasification slag,significantly increasing the formation of C-S-H gel,C-（A）-S-H gel,and acicular ettringite.Ettringite enhances the material’s density and integrity by forming a reinforcing structure,bridging cracks,and filling pores.TG,FTIR,and SEM analyses confirmed the chemical basis of the composite synergistic effect,indicating that the ternary system cementitious material has excellent mechanical properties and microstructure.（4）The mechanism of slag and sodium sulfate co-triggered dissolution-gelation process and ettringite nucleation-filling effect was explored,and the constraint relationship between sodium sulfate dosage threshold and expansion crack was clarified.The addition of slag promotes the formation of C-S-H and C-A-S-H gels,optimizing the microstructure.Moreover,the introduction of an appropriate amount of Na₂SO₄（10%）further promotes the formation of C/N-A-S-H gel and ettringite（AFt）through synergistic effects,significantly increasing the material’s early and later compressive strength（reaching 17.45 MPa at 3 days and 30.29 MPa at 28 days）.However,excessive Na₂SO₄（>10%）leads to overproduction of ettringite,causing volume expansion and microcracks,thereby reducing material performance.XRD,TG,FTIR,SEM,and MIP analyses indicate that the synergistic action of slag and Na₂SO₄ significantly enhances the dissolution of silicoaluminous substances and the formation of gel phases,optimizes the pore structure,and increases the matrix density.Therefore,the addition of an appropriate amount of slag and Na₂SO₄ can significantly improve the mechanical properties and microstructure of the cementitious material,but the dosage of Na₂SO₄ must be strictly controlled to avoid adverse effects.（5）An eco-friendly mortar based on industrial by-product slag was developed.The influence law of sediment content on material properties was revealed,achieving synergistic enhancement of solid waste resource utilization and low-carbon preparation.Both mechanical properties and environmental benefits were taken into account.The results show that as the replacement ratio of bottom mud increases（from 0%to 100%）,the mortar flowability significantly decreases（by more than 43%）,and the compressive and flexural strengths exhibit a stepwise downward trend.When the bottom mud content is controlled within 50%,the 28-day compressive strength of the eco-friendly mortar can reach 25.8 MPa,meeting the requirements of M 20 mortar.The high specific surface area,strong water absorption,and inert nature of the bottom mud leaded to a reduction in hydration products,an increase in porosity,and a looser microstructure.However,by reasonably controlling the bottom mud content,the pore structure can be optimized,and the mechanical properties of the mortar can be maintained.Moreover,the total carbon emissions of the eco-friendly mortar prepared from industrial by-products are only 42.6 kg CO₂/m³,which is significantly lower than that of ordinary mortar（506.2 kg CO₂/m³）.This indicates that the eco-friendly mortar has significant potential for solid waste resource utilization and environmental benefits while ensuring mechanical performance.更多还原