垃圾焚烧飞灰预处理后水泥固化实验研究

为实现焚烧飞灰的无害化和资源化,采用对飞灰进行预处理后再与水泥混合固化的方法来处理飞灰,并比较了不同方式的处理效果:(1)用去离子水润湿飞灰再厌氧堆放24 h后用水泥固化;(2)用绿矾溶液处理后再用水泥固化;(3)飞灰直接与水泥混合固化.研究3种方式所得水泥固化砌块试件强度的发展和控制重金属浸出的效果与直接固化物的对比,研究结果表明:在飞灰与水泥的质量比相同的条件下,采用先用绿矾处理飞灰再进行固化的处理方式,不但稳定重金属的效果好,而且试件强度最高,有望加以应用.     

垃圾焚烧飞灰预处理后水泥固化实验研究

为实现焚烧飞灰的无害化和资源化，采用对飞灰进行预处理后再与水泥混合固化的方法来处理飞灰，并比较了不同方式的处理效果：（1）用去离子水润湿飞灰再厌氧堆放24h后用水泥固化；（2）用绿矾溶液处理后再用水泥固化；（3）飞灰直接与水泥混合固化。研究3种方式所得水泥固化砌块试件强度的发展和控制重金属浸出的效果与直接固化物的对比，研究结果表明：在飞灰与水泥的质量比相同的条件下，采用先用绿矾处理飞灰再进行固化的处理方式，不但稳定重金属的效果好，而且试件强度最高，有望加以应用。     

电镀污泥的固化及浸出毒性研究

采用水泥和细砂作固化基材处理含Ni、Cr、Cu等重金属的电镀污泥,对固化块的浸出试验表明:水泥固化该电镀污泥效果良好,固化过程中加入适当的螯合剂KS-3,可以提高固化效果,并对固化块在不同pH浸取剂下的重金属浸出浓度进行了研究。     

电镀污泥的固化及浸出毒性研究

采用水泥和细砂作固化基材处理含Ni、Cr、Cu等重金属的电镀污泥,对固化块的浸出试验表明:水泥固化该电镀污泥效果良好,固化过程中加入适当的螯合剂KS-3,可以提高固化效果,并对固化块在不同pH浸取剂下的重金属浸出浓度进行了研究.     

电镀污泥的固化及浸出毒性研究

采用水泥和细砂作固化基材处理含Ni、Cr、Cu等重金属的电镀污泥，对固化块的浸出试验表明：水泥固化该电镀污泥效果良好，固化过程中加入适当的螯合剂KS-3，可以提高固化效果，并对固化块在不同pH浸取剂下的重金属浸出浓度进行了研究。     

火焰原子吸收光谱法在分析污泥焚烧飞灰中重金属化学形态上的应用

应用微波消解-火焰原子吸收光谱法(FAAS)测定污泥焚烧飞灰中的Cd、Cr、Cu、Mn、Ni、Pb、Zn等各重金属元素总量。研究发现,样品用HNO3-HF混合酸经微波消解后, 溶解时间由原来的3～5 h缩短到30 min。选择合适的分析谱线, 用FAAS直接测定试液中上述7种重金属元素各自总量及其不同形态含量,所得各元素的线性相关系数均大于0.999 0。分析结果表明,污泥焚烧飞灰中重金属Zn, Pb, Mn含量较高, 而Ni的含量较低; 污泥焚烧飞灰中含有的重金属除Cr相对比较稳定外, 其它重金属元素的不稳定态所占比例均很高。 处置污泥焚烧飞灰时应选择不同的处置和利用方式,尽可能地将污泥焚烧飞灰中重金属的化学形态由不稳定态转变为稳定态。     

螯合剂处理生活垃圾焚烧飞灰的稳定化技术研究与实践

基于生活垃圾焚烧飞灰的危害,介绍了固化、熔融烧结和化学药剂稳定化等焚烧飞灰的主要处置技术,分析了某生活垃圾焚烧发电厂飞灰的主要成分和性质。根据分析结果,选择采用3%的DTC类有机螯合剂和1.5%的磷酸三钠作为稳定化药剂,同时加入15%的稳定化用水量,配入飞灰螯合处理系统。固体废物浸出毒性试验对应用实践的验证结果显示,焚烧飞灰在使用复合稳定化药剂后,可以使飞灰中的重金属稳定化效果达到控制标准[4]的入厂要求。     

水泥稳定碎石基层不同成型方式下力学强度分析

针对目前水泥稳定碎石基层不同成型方式导致层问不同接触与黏结情况,研究了在这些条件下水泥稳定碎石上下基层层间剪切力大小,以及水泥稳定碎石梁式试件抗弯拉强度.结果表明:与层间铺洒水泥浆和直接分层成型试件相比,一次成型试件抗剪强度大大增加;分层成型和界面受到污染试件与一次成型试件比较,试件整体性下降,弯拉强度降低.     

微波消解-电感耦合等离子体原子发射光谱法分析垃圾焚烧飞灰中重金属元素

应用微波消解和电感耦合等离子体原子发射光谱法(ICP-AES)测定垃圾焚烧飞灰中的Cd,Cr,Cu,Mn,Ni,Pb,Zn等7种重金属元素。考察了飞灰的最佳微波消解条件,样品用HNO3-HCl-HF-H3BO3混合酸经微波消解后,溶解时间由原来的3～5h缩短到20min。选择合适的分析谱线,试液直接用ICP-AES同时测定上述7种重金属元素,所得各元素的线性关系良好,相关系数均大于0.9990,方法的检出限在0.0005～0.008μg/mL之间。所建立的方法应用于垃圾焚烧飞灰中痕量重金属元素的测定,回收     

某铅锌矿废石尾矿固化/稳定化处理试验研究

基于广西某铅锌矿废石尾矿需要处理的现状,对其污染特性进行判别,以选择适宜的固化剂和稳定剂进行固化/稳定化试验研究。试验结果表明:1)某铅锌矿废石尾矿属于Ⅱ类固废;2)选取磷酸一铵为稳定剂、水泥和粉煤灰为固化剂;3)当废石尾矿样品中只加入稳定剂磷酸一铵时,可以实现较好的重金属控制效果,达到第Ⅰ类固废的标准;4)当固化剂水泥和稳定剂磷酸一铵共同作用时,可以实现最优的重金属污染物控制效果,但样品的pH值不能满足要求;5)废石尾矿样品中粒径大于5 cm的部分仍具有重金属污染毒性,在对废石尾矿进行固化/稳定化处理之前应先对其进行筛分破碎预处理。     

胶结充填用冶金渣协同垃圾焚烧飞灰固镉机理

胶结充填采矿协同利用垃圾焚烧飞灰是解决飞灰日益激增的新思路,可大量资源化利用飞灰并固化其中的重金属离子.本文以矿渣-钢渣基胶凝材料(简称冶金渣胶凝材料)分别结合4种城市垃圾焚烧(MSWI)飞灰制备胶凝材料,并以全尾砂作为骨料制成胶结充填料,测定充填料试样的流动度、抗压强度以及Cd2+浸出质量浓度:冶金渣-垃圾焚烧飞灰基充填料试样的流动度为240~265 mm,满足矿山充填的泵送要求;28 d抗压强度均大于8.88 MPa,满足一般矿山充填1~6.5 MPa的强度要求;Cd2+浸出液质量浓度低于饮用水标准5 μg·L-1的限值.通过X射线衍射(XRD)、红外光谱(IR)和热重-差示扫描量热法(TG-DSC)分析表明胶凝材料的主要水化产物组成为钙矾石、Friedel盐和C-S-H凝胶;通过X射线光电子能谱(XPS)发现Cd2+对Al2+的结合能有较大影响,钙矾石、Friedel盐可能对镉离子有固化作用.      

垃圾焚烧飞灰熔融无害化及资源化研究现状

垃圾焚烧飞灰因含二噁英和重金属被列为危险废物（HW18）,存在环境污染风险,2020年全国生活垃圾焚烧量高达14607.6万吨,以焚烧量5%（质量分数）计算,全国垃圾焚烧飞灰的产生量为730.4万吨。目前垃圾焚烧飞灰以固化填埋为主,占用土地资源,且堆存量与处理量严重失衡,无法实现资源化,因此垃圾焚烧飞灰的无害化及资源化已成为绿色发展的瓶颈课题。本文详细介绍了垃圾焚烧飞灰经熔融无害化及资源化的研究现状,阐述了熔融处理垃圾焚烧飞灰的重金属固化、二噁英降解机理,结合熔融形成的玻璃渣分析了制备微晶玻璃、泡沫微晶玻璃、胶凝材料的资源化技术,并指出现有玻璃化虽能固化重金属,但在后续资源化以及产品服役过程,重金属的迁移规律、浸出性需要进一步研究,为垃圾焚烧飞灰的综合利用提供了参考。      

外加剂对水泥固化铁矾渣性能的影响

在硅酸盐水泥熟料中加入铁矾渣,制备成胶凝材料.分别以粉煤灰沸石、硫化钠和粉煤灰为外加剂,研究其对水泥固化体强度和浸出毒性的影响.在胶凝材料中铁矾渣加入量为60%时,加入沸石、硫化钠为稳定剂,均可提高重金属离子的稳定性,不同固化体的浸出毒性值均低于国家标准.在胶凝材料中加入粉煤灰,粉煤灰掺量增加,固化体强度下降,不同固化体的浸出毒性值也均低于国家标准.     

高炉喷吹垃圾焚烧飞灰预处理工艺分析

为了解决高炉协同处置垃圾焚烧飞灰时氯负荷高的问题,以去离子水作为洗脱剂,通过考查不同水洗条件(水灰比、水洗时间、水洗温度、水洗次数)下垃圾焚烧飞灰中Cl元素和重金属元素的脱除效果,对飞灰高炉焚烧固化预处理中的工艺参数进行研究。结果表明,飞灰中Cl主要以NaCl、KCl、CaClOH的形式存在。在高炉协同处理前水洗预处理的适宜条件为水灰比为4 ml/g、水洗时间为5 min、水洗温度为25 ℃、水洗1次。在此条件下飞灰中Cl脱除率为86.45%、Zn脱除率为4.77%、Pb脱除率为35.65%、Cu脱除率为7.63%、Cr脱除率为9.71%。水洗后飞灰的配加比例、单位时间喷吹量、喷吹速度需按企业自身情况确定。在高炉喷煤比为139.12 kg/t(Fe)和飞灰喷吹量为喷煤量的1%条件下,由水洗后飞灰带入高炉的Cl质量为0.078 kg/t(Fe)、Zn为9.74×10-3 kg/t(Fe)、Pb为1.53×10-3 kg/t(Fe)、Cu为8.35×10-4 kg/t(Fe)、Cr为9.88×10-5 kg/t(Fe),远低于一般高炉熔炼要求,可以满足高炉正常运行需求。     

Research on the Solubility of Radioactive Elements in the Ashes from the Soma in Turkey

Coal combustion results in wastes such as fly ash, slag, and flue gases. In Turkey, approximately 45 million tons of coals are fired annually and consequently around 20 million tons of fly ashes are produced. Such large volumes of ash pose a significant problem both for society and the environment. Furthermore, significant amounts of uranium and thorium are often encountered in these ashes. These concentrations are relatively higher for ashes from younger age lignites. Within the scope of this study, a series of characterization tests were performed on samples taken from Soma thermal power plant, one of the largest in Turkey. Characterization studies include particle size analysis, moisture analysis, density determination, pH profile measurements, chemical analyses, and mineralogical analyses. Leach tests with sulfuric acid (H₂SO₄) were then performed. The leaching of the radioactive minerals (uranium and thorium) with the help of sulfuric acid in the ashes was examined and the optimum leaching parameters were investigated. The recovery opportunities of uranium and thorium metals in the ashes were addressed. The results indicated that under optimum conditions, 94.71% uranium dissolution efficiency and 93.21% thorium dissolution efficiency were obtained.     

高炉喷吹垃圾焚烧飞灰预处理工艺分析

为了解决高炉协同处置垃圾焚烧飞灰时氯负荷高的问题,以去离子水作为洗脱剂,通过考查不同水洗条件(水灰比、水洗时间、水洗温度、水洗次数)下垃圾焚烧飞灰中Cl元素和重金属元素的脱除效果,对飞灰高炉焚烧固化预处理中的工艺参数进行研究。结果表明,飞灰中Cl主要以NaCl、KCl、CaClOH的形式存在。在高炉协同处理前水洗预处理的适宜条件为水灰比为4 ml/g、水洗时间为5 min、水洗温度为25℃、水洗1次。在此条件下飞灰中Cl脱除率为86.45%、Zn脱除率为4.77%、Pb脱除率为35.65%、Cu脱除率为7.63%、Cr脱除率为9.71%。水洗后飞灰的配加比例、单位时间喷吹量、喷吹速度需按企业自身情况确定。在高炉喷煤比为139.12 kg/t(Fe)和飞灰喷吹量为喷煤量的1%条件下,由水洗后飞灰带入高炉的Cl质量为0.078 kg/t(Fe)、Zn为9.74×10^-3 kg/t(Fe)、Pb为1.53×10^-3 kg/t(Fe)、Cu为8.35×10^-4 kg/t(Fe)、Cr为9.88×10^-5 k...     

Performance and Leaching Assessment of Flowable Slurry

This project was conducted to evaluate the performance and leaching of controlled low strength materials (CLSM) incorporating fly ash and foundry sand. Two different CLSM (or flowable slurry) reference mixtures (equivalent to available production CLSM mixtures) were proportioned for unconfined compressive strength levels in the range of 0.3–0.7 MPa (50–100 psi), at 28 days, using two sources of ASTM Class F fly ash. For each reference mixture, other mixtures were proportioned using two sources of foundry sand (molten metal-casting mold sand) as a replacement for fly ash in the range of 30–85%. The ingredients of the slurry mixtures—fly ash, clean foundry sand, and used foundry sand—were tested for their physical and chemical properties and their leachate characteristics. Portland cement used as the primary binder was also tested for its properties. All CLSM mixtures made with and without foundry sand were evaluated for settlement, setting and hardening characteristics, compressive strength, permeability, and leachate characteristics. The leachate results of these CLSM-making materials were below the enforcement standards (ES) of the Wisconsin Department of Natural Resources (WDNR) ground-water quality standards (GWQS). They also met practically all the parameters of the drinking water standards. A number of CLSM mixtures incorporating fly ash and foundry sand are recommended for construction applications.     

铁尾矿粉制备高延性纤维增强水泥基复合材料

探索采用铁尾矿粉取代粉煤灰作为矿物掺合料制备高延性纤维增强水泥基复合材料（ECC）的可行性,重点研究铁尾矿粉掺量对ECC的拉伸特性和抗压强度的影响,并比较所研发的新型铁尾矿粉ECC与传统粉煤灰ECC的宏观力学性能.研究发现,采用铁尾矿粉作为矿物掺合料制备高延性纤维增强水泥基复合材料是可行的.在同等矿物掺合料掺量下,铁尾矿粉ECC的强度性能低于粉煤灰ECC,但表现出更强的拉伸延性.在所研制的铁尾矿粉ECC中,当铁尾矿粉与水泥质量比为1.2-2.2时,ECC的28 d抗压强度为36.7-54.2 MPa,满足一般混凝土结构对抗压强度的要求.此时,ECC的28 d极限拉伸应变为3.4%-4.3%,铁尾矿的总用量占固体基体原材料总质量的66.6%-77.0%.      

高炉锰铁水淬矿渣活性的研究

深入地探讨了锰铁高炉水淬矿渣的利用。对其潜在水硬性、火山灰性进行了试验研究，测试了水泥试件的抗压强度比，并与普通生铁高炉矿渣、粉煤灰的活性作了对比。     

Mechanical Stabilization of Cemented Soil–Fly Ash Mixtures with Recycled Plastic Strips

An experimental investigation was undertaken to evaluate the mechanical behavior of a soil–cement–fly ash composite, reinforced with recycled plastic strips (high-density polyethylene) that were obtained from postconsumer milk and water containers. The primary motivation for the study was to investigate the innovative reuse of several candidate waste materials in geotechnical and pavement applications. The specific objectives of the research were: (1) to evaluate the compressive, split tensile, and flexural strength characteristics of the material, and (2) to determine the effectiveness of recycled plastic strips in enhancing the toughness characteristics of the composite. Since cement-stabilized materials are weak in tension, the main focus of the experimental program was to conduct a series of specially instrumented split tensile and flexural tests on mixes containing various amounts of cement, fly ash, and plastic strips. For a meaningful comparison of test results, all specimens were prepared at a constant dry density. The standard ASTM C496 procedure for split tensile test was slightly modified by attaching two horizontal linear variable differential transformers (LVDTs) to measure the diametral deformation of the specimen due to compressive loading in an orthogonal direction. This modification enabled the evaluation of the postpeak toughness behavior of the composite. For some specimens, a strain gauge was attached to the middle of the face perpendicular to the loading plane in order to correlate the results with the one found using the LVDTs. All tests were performed with a 90 kN universal testing machine with deformation control. Experimental data show that the soil–cement matrix stabilized with 4% to 10% by weight of fly ash and reinforced with 0.25% to 0.5% (by weight) plastic strips (having lengths of 19 mm or 38 mm) can achieve a maximum compressive strength of 7000 kPa, a split tensile strength of 1000 kPa, and a flexural strength of 1200 kPa. These ranges in strength values are suitable for a high-quality stabilized base course for a highway pavement. To quantify the reinforcing effects in the postpeak region, a dimensionless toughness index is proposed. It is found that the use of fiber reinforcement significantly increases the postpeak load carrying capacity of the mix and thus the fracture energy. It is concluded that the lean cementitious mix containing recycled materials offer a lot of promise as an alternative material for civil engineering construction.