城市生活垃圾焚烧飞灰水泥固化技术研究

用硫铝酸盐水泥对城市垃圾焚烧飞灰(简称飞灰)进行固化实验,研究了飞灰重金属浸出特性,分析了飞灰掺量、浸提剂p H值对重金属浸出特性以及飞灰掺量对不同龄期(3、7、28 d)飞灰固化体抗压强度的影响,并对飞灰及其固化体进行XRD分析。结果表明,在HJ/T 299-2007和HJ/T 300-2007两种不同浸出体系下,飞灰中Cu、Zn、Cd、Pb、Cr和Mn等重金属浸出浓度差别较大,建议应根据评价目标合理选择重金属浸出测量方法。其中,飞灰中Pb的浸出浓度超过《危险废物鉴别标准浸出毒性鉴别》(GB 5085.3-2007)限值的3.35倍,因此被列为危险废物,应妥善处理。除飞灰掺量小于40%时的固化体Cd符合标准,其余飞灰固化体Pb和Cd的浸出浓度仍超过《生活垃圾填埋场污染控制标准》(GB 16889-2008)限值,故达不到卫生填埋的要求。固化体抗压强度随飞灰掺量增大而降低,重金属浸出浓度与之相反。飞灰掺量为40%时,固化体中重金属浸出浓度随浸提剂p H值降低而增大,但p H值大于5时,未测出重金属浸出。XRD结果表明:飞灰中可溶性盐参与水泥水化反应,重金属Cr以CrO_2-4的形式固化于钙矾石中。     

螯合剂稳定化飞灰中Pb和Cd浸出行为研究

考察了螯合剂稳定化飞灰(以下简称螯合灰)中重金属Pb、Cd的浸出特性。结果表明,各螯合灰样品中Pb总浓度均高于Cd,经醋酸缓冲液浸提后,各样品中Pb、Cd的浸出浓度均超过《生活垃圾填埋场污染控制标准》(GB 16889—2008)的标准限值,且Pb超标倍数均高于Cd。样品中Pb的浸出行为表现为高浸出浓度低浸出率,而Cd则为高浸出率低浸出浓度。浸提前后各螯合灰样品中Pb、Cd均以铁锰氧化物结合态为主,在醋酸浸提过程中,螯合灰中的Pb、Cd均易再次形成不溶性的碳酸盐或氢氧化物沉淀,因此在中性或偏酸性环境中依然存在较大浸出风险。     

不同粒径垃圾焚烧飞灰金属形态分布比较研究

研究了华南地区某垃圾焚烧厂的除尘器飞灰的化学组成和粒径分布,并采用分级提取法对不同粒径飞灰中的重金属化学形态进行了研究。同时比较了华南、华东、西南地区以及台湾地区垃圾焚烧飞灰的筛下累积分布和不同粒径飞灰中各重金属组成。结果表明,飞灰的组要成分为：CaO、SiO2和SO3等;各地区75%的飞灰粒径都主要集中在38.5～75μm。华南地区各粒径飞灰中挥发性金属（Zn和Pb）含量明显高于其他金属。除Ni和Cr外,Cu、Zn、Pb和Cd含量随粒径减小呈先减少后增大的趋势。华南地区Cu、Zn、Ni、Cr、Pb和Cd的含量均高于其他地区（台湾地区除外）。Cu、Zn和Cd的弱酸提取态和可还原态含量较高。高于40%的水溶态Pb表明其对环境有较大潜在危害;40%Ni和Cr主要以残渣态存在,对环境的潜在影响较小。     

用通用浸提剂Mehlich 3研究城市污泥重金属生物有效性

采用Mehlich3(M3)通用浸提剂对经稳定化处理的城市污泥中重金属元素Cd、Cr、Pb、Ni、Zn、Cu的有效态进行提取,同时进行了小麦盆栽试验,将M3通用浸提剂浸提所得的重金属元素有效态含量与该元素在小麦幼苗茎叶和根系中的元素的富集量进行相关分析.结果表明,城市污泥中不同元素的有效态含量明显不同.M3提取的有效态Cd、Cr、Cu与幼苗茎叶富集Cd、Cr、Cu极显著相关,但Pb、Ni、Zn的有效态含量与植物茎叶富集量相关性不明显,主要原因可能与元素从植物根系向茎叶迁移能力有关.M3提取的污泥中重金属的有效态含量与小麦幼苗根系富集的重金属元素的含量呈现显著的相关性.因而M3可用于污泥中重金属元素潜在的生物有效性评价.     

水泥对垃圾焚烧飞灰中重金属的固化研究

采用水泥固化法处理垃圾焚烧飞灰,研究了飞灰与水泥质量比、养护时间、添加剂和化学预处理对垃圾焚烧飞灰固化块中重金属Zn、Pb、Cu、Cd、Cr浸出的影响.结果表明,当飞灰与水泥质量比为3:4,养护时间为11d的条件下,以砂浆塑化剂为添加剂,固化块Pb、Cu、Cd和Cr的浸出浓度分别降低了72.4％、70.6％、60.0％...     

垃圾焚烧飞灰对染料（亚甲基蓝）的吸附性能

以垃圾焚烧飞灰为吸附剂对亚甲基蓝进行了吸附脱色实验。主要探讨了飞灰粒径、用量、温度、pH值和初始浓度等因素对亚甲基蓝吸附的影响，同时分析了吸附上清液中重金属Pb和Cr的浸出毒性。研究结果表明，在25—45℃、pH值2～12、飞灰用量1～5g范围内，经过180min吸附，亚甲基蓝的脱色率都达75％以上，最高可达99．46％。实验还得出，除重金属Pb外，吸附上清液中重金属的浸出量远远低于《危险废物鉴别标准浸出毒性鉴别》的限定值。因此，若能降低重金属Pb的浸出，飞灰将具有应用于处理染料废水的巨大潜力。     

不同方法处理飞灰对亚甲基蓝的吸附性能

为了研究不同方法处理飞灰对亚甲基蓝的吸附性能和吸附上清液中重金属的浸出毒性,分析了水洗、硫酸洗和醋酸洗飞灰及在吸附过程中投加NaOH和Na2 CO3对亚甲基蓝的吸附效果的影响,以及吸附上清液中Pb和Cr的浸出情况.实验得出,不同方法处理飞灰对亚甲基蓝的脱色率均达70％以上,最高可达100％,通过水洗和酸洗,飞灰的稳定性显著提高,1％硫酸和5％醋酸洗飞灰吸附上清液中Pb和Cr的浸出量远远低于《危险废物鉴别标准浸出毒性鉴别》的限定值.飞灰经过稳定化处理,用以处理染料废水具有巨大潜能.     

自然堆存下的飞灰污染物浸出毒性研究

测定了飞灰的主要组成成分和重金属元素含量。生活垃圾焚烧飞灰在2年期的自然堆存下，通过分析不同时期污染物浸出特性，以研究飞灰污染物自然老化特征。结果表明：飞灰的主要组成元素有Ca、Si、Al、S、K、Na、Fe、Mg和Cl等，其重金属元素含量大约占1%。飞灰自然老化后，Pb 、Zn 、Cr^6＋、Hg和氰化物的迁移性大大降低；Cu 、As和Cd变化不明显，Cr的浸出略有增加；飞灰中的重金属元素在低pH下仍不具有长期稳定性，因而具有较大的环境风险。     

预处理飞灰重金属的固定化效果及环境影响评估

针对垃圾焚烧飞灰广泛存在重金属超标的问题,采用哌嗪螯合剂、二甲基二硫代氨基甲酸盐及水泥对飞灰进行预处理,以降低填埋风险。通过《固体废物浸出毒性方法醋酸缓冲溶液法》(HJ/T300-2007)探讨预处理对飞灰中重金属的固定效果,并采用X射线衍射、扫描电镜和BCR形态提取分析各飞灰的物相组成、微观形貌和重金属形态分布,使用RAC和STI模型对各飞灰进行环境风险评估。结果表明,原灰中重金属Ni、Pb、Cd的浸出毒性超标,重金属含量呈Zn>Pb>Cu>Cd>Cr>Ni顺序分布。预处理作用后,飞灰中重金属Ni、Cd、Pb的浸出毒性满足标准限值,固定率达99%以上,未超标重金属Cr、Zn、Cu的固定率高于96%。同等添加量下,SDD的稳定效果优于TS300,但TS300协同水泥固定重金属的作用优于SDD。稳定化对Cr的处理效果优于固化/稳定化,单一水泥固化对Zn、Pb、Ni的固定作用最佳,但40%的水泥用量及高增容比限制了水泥固化的应用。ANC测试表明,水泥固化的ANC最强。XRD和SEM分结果表明,稳定化形成的新矿物对重金属的固定起重要作用,水泥水化生成的Ca(OH...     

水泥对垃圾焚烧飞灰的固化处理试验研究

对垃圾焚烧飞灰的化学成分、重金属物质的含量及浸出浓度进行测试分析.结果表明,飞灰中Pb和Cr等重金属物质浸出量超过浸出毒性标准,因而被认为是危险废物,必须进行固化处理.还考察了水泥对焚烧飞灰中重金属物质固化的效果,研究表明当飞灰掺量适当时,重金属物质的固化效果良好.重金属物质通过物理固封、替代,沉淀反应和吸附等形式可固化进水泥水化产物结构中.     

Extraction of heavy metals from MSW incinerator fly ash using saponins

An extraction process with saponins was evaluated for removing heavy metals from MSW (municipal solid waste) incinerator fly ashes. Two different fly ashes, A and B, were treated on a laboratory scale with three triterpene-glycoside type of saponins, M, Q, and T, in the pH range 4-9. The results were compared with those of the HCI and EDTA treatment. The treatment with saponins extracted 20-45% of Cr from the fly ashes. Saponins were also effective in extracting Cu from fly ash A attaining 50-60% extraction. Saponin T extracted 100% of Pb from fly ash A at pH around 4. The extraction of Zn with the saponin treatment was similar to that of the HCl treatment. Further, Cr, Cu, Pb, and Zn were fractionated by sequential extraction to investigate the effect of saponins on each fraction. Extraction behavior of other elements during the saponin treatment was also studied. The leaching test on the residues received after the saponin treatment showed that the fly ashes were successfully detoxified to meet the landfilling guideline.     

危险废物焚烧飞灰中重金属的稳定化处理

以上海市某危险废物焚烧厂飞灰为研究对象,采用Na2S、FeSO4、Na3PO4、和Na3C3N3S34种不同类型化学稳定药剂对飞灰进行了稳定化处理,并应用XRD、IR、SEM和连续化学提取法等仪器和手段对Na3C3N3S3处理焚烧飞灰的产物进行分析研究。研究结果表明,Na3C3N3S3对飞灰中的重金属Cr、Pb、Zn的稳定效果最好,Na3PO4对Cr无明显稳定效果。稳定后产物表面变得致密化,Na3C3N3S3与重金属离子生成的沉淀物干燥后无明显晶型存在。经稳定处理后飞灰中的重金属形态由弱酸提取态转化为可氧化态,减少了飞灰中重金属的浸出毒性。     

Leaching characteristics of stabilized/solidified fly ash generated from ash-melting plant

This study was designed to elucidate the leaching characteristics of stabilized/solidified (S/S) fly ash generated by ash-melting. For this study, pH-dependent leaching tests, sequential extraction procedures, and column leaching tests were carried out. The pH-dependent leaching test results for Pb, Cu, and Zn showed that the heavy metal concentrations in the high-pH range were lower than the predicted values for hydroxide and carbonate. During sequential extraction, Cu and Pb were principally distributed in the S/S ashes' organic matter fraction in the chelating agent, suggesting that metals bind to the chelating agent. The percentage of the water-soluble fraction for Pb and Cu was low (<0.2 %). The fly ashes treated with a chelating agent and cement had low leachability potential for metals in the high-pH range. Column tests for S/S fly ashes showed that two leaching stages were distinguishable: one for short time, corresponding to faster metal leaching, and another for the leaching rate. Kinetic speciation was then applied to data obtained from column leaching tests. The first-order reaction/diffusion model showed a better fit for Ca, Pb, and Cu, suggesting that the initial dissolution of soluble compounds, such as metal chloride, was controlled by the first-order reaction (surface wash off). Subsequently, insoluble compounds such as hydroxide or carbonate might penetrate into the porous matrix by diffusion.     

城市生活垃圾焚烧处理过程中重金属迁移规律研究

通过采集厦门2个垃圾焚烧发电厂进厂垃圾、渗滤液、飞灰、炉渣和烟气样品，分析垃圾组成成分及各组分的重金属含量，结果表明，垃圾中以厨余、橡塑类和纸类为主，共占到垃圾干基的78．08％，重金属含量大小次序为Zn〉Cu〉Pb〉Cr〉Ni〉Cd〉Hg；垃圾渗滤液中除Zn外，其他金属的含量都较低，一厂渗滤液中重金属Ni、Zn迁移量较大，分别达到24．46％和8．52％。二厂渗滤液中重金属的迁移有相同的趋势，但含量相对较高。垃圾焚烧后其重金属主要分布在飞灰和废渣中，烟气中的含量非常少，不同金属的含量均有差别，这与金属的性质有很大关系；通过浸出毒性分析，飞灰中重金属酸溶态含量多，容易浸出，属于危险废物。同时，不同烟气处理工艺产生的飞灰的重金属浸出量有很大差别。     

SGA对垃圾焚烧飞灰中重金属的固化性能研究

根据EPA1311、HJ／T299—2007、HJ／T300—2007和HJ557—2009等国内外不同标准，研究了深圳某垃圾焚烧发电厂垃圾焚烧飞灰的浸出毒性，探讨了六硫代胍基甲酸（sixthioguanidineacid，SGA）、二甲基二硫代氨基甲酸盐（sodiumdimethyldithiocarbamate，SDD）和Ca（OH）2浓度对垃圾焚烧飞灰中重金属的固定性能的影响。研究结果表明，随着浸提液pH的降低，该厂焚烧飞灰中大部分金属元素的浸出量增大，焚烧飞灰浸出液中的cd、Ni、Ph和zn浓度分别超过国家危险废物鉴别标准（GB5085．3—2007）规定值的4．75倍、1．47倍、6．72倍和2．20倍，属于危险废弃物，必须进行稳定化处理。当固化剂SGA加入量为0．1mol／kg时，稳定化后的重金属浸出浓度已经低于危险废物鉴别标准，且对Cd、Cr、Cu和Pb的固化性能优于SDD和Ca（OH）2；当固化剂SGA、SDD和Ca（OH）2加入量为0．5mol／kg时，稳定化后的焚烧飞灰重金属浸出浓度均低于国家危险废物鉴别标准（GB5085．3-2007）中的规定值。与SDD和Ca（OH）：相比，SGA对垃圾焚烧飞灰中重金属的固化处理更具有优势。     

Stabilisation of MSWI bottom ash with sulphide-rich anaerobic effluent

Effluent of an anaerobic sulphate-reducing wastewater treatment process was used to stabilise bottom ash. The effect of stabilisation on the concentration and binding of Ca, P, S, Cu, Pb, Zn, As, Cr, and Mo were studied by comparing results of sequential extraction from fresh and stabilised bottom ash. The stabilisation treatment improved the retention of Ca, Cu, Pb, S, and Zn in bottom ash compared to a treatment with ion-exchanged water. In addition to retention, Cu, S, and Zn were accumulated from the anaerobic effluent in the bottom ash. Concentrations of As, Cr, and Mo remained on the same level, whereas leaching of P increased compared to control treatment with ion-exchanged water. Improved retention and accumulation were the result of increased binding to less soluble fractions. The highest increases were in the sulphide and organic carbon bound fraction and in the carbonate fraction. Enhanced carbonation was probably due to CO2 deriving from the degradation of organic carbon. Flushing of stabilised bottom ash with ion-exchanged water ensured that the observed changes were not easily reversed. Most of the sulphide in the anaerobic effluent was removed when it was passed through bottom ash. The objective was to study the feasibility of sulphide-rich anaerobic effluent in bottom ash stabilisation and changes in the binding of the elements during stabilisation. In addition, the ability of the process to remove sulphide from the effluent was observed.     

SGA对垃圾焚烧飞灰中重金属的固化性能研究简

根据EPA 1311、HJ/T 299-2007、HJ/T 300-2007和HJ 557-2009等国内外不同标准，研究了深圳某垃圾焚烧发电厂垃圾焚烧飞灰的浸出毒性，探讨了六硫代胍基甲酸（sixthio guanidine acid，SGA）、二甲基二硫代氨基甲酸盐（sodium dimethyl dithio carbamate，SDD）和Ca（OH）₂浓度对垃圾焚烧飞灰中重金属的固定性能的影响。研究结果表明，随着浸提液pH的降低，该厂焚烧飞灰中大部分金属元素的浸出量增大，焚烧飞灰浸出液中的Cd、Ni、Pb和Zn浓度分别超过国家危险废物鉴别标准（GB5085.3-2007）规定值的4.75倍、1.47倍、6.72倍和2.20倍，属于危险废弃物，必须进行稳定化处理。当固化剂SGA加入量为0.1 mol/kg时，稳定化后的重金属浸出浓度已经低于危险废物鉴别标准，且对Cd、Cr、Cu和Pb的固化性能优于SDD和Ca（OH）₂；当固化剂SGA、SDD和Ca（OH）₂加入量为0.5 mol/kg时，稳定化后的焚烧飞灰重金属浸出浓度均低于国家危险废物鉴别标准（GB 5085.3-2007）中的规定值。与SDD和Ca（OH）₂相比，SGA对垃圾焚烧飞灰中重金属的固化处理更具有优势。     

Leaching Dynamics Studies of Municipal Solid Waste Incinerator Ash

Abstract

An assessment of the short- and long-term hazards from municipal solid waste incinerator (MSWI) ash is made through the elemental analysis of 40 to 50 elements in the ash and leachates produced by several leaching procedures. The ash was analyzed using neutron activation analysis (NAA) and x-ray fluorescence (XRF). The leachates were analyzed using NAA and inductively-coupled plasma atomic emission spectroscopy (ICP). The leaching dynamics of an ash monofill were modelled with a series of extractions using simulated acid rain. An initial spike of the metals Ag, Ba, Be, Cr, Cu, Mo, Pb, Sr, and Zn in the leachates appears to be the greatest hazard posed by MSWI ash monofills. The elements As, Cd, Cu, Hg, Pb, S, and Zn were identified as potential long term hazards utilizing a sequential extraction procedure which approximates the total amount of the elements available over the lifetime of the monofill.

The pH of the resulting leachate is the single greatest factor governing the concentration of metals in solution, more important than the concentration of the element in the ash. These results are applied to an assessment of the suitability of the Toxicity Characteristic Leaching Procedure (TCLP) in measuring leaching potential of an MSWI ash monofill.     

污泥焚烧底灰中重金属残留特性的实验研究

利用原子吸收分光光度计和程序控制温升炉研究了沈阳市污水处理厂污泥在不同焚烧工况下重金属Cu、Cr、Cd、Zn、Ni和Pb在焚烧底灰中的残留特性。考察了升温速率、焚烧温度、含水率以及停留时间等因素对重金属在污泥底灰中的残留特性的影响。实验表明 ,Pb、Cd和Cu在灰渣中的残留率随着温度和停留时间的增加而降低。大部分的重金属元素Zn、Cu和Cr残留在灰渣中 ,Cd、Pb和Ni部分残留在灰渣中