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摘要: 文章研究了福建某垃圾焚烧厂飞灰的化学、矿物学特征以及不同处理工艺对飞灰中重金属脱除效率的影响。结果表明:垃圾焚烧飞灰表面结构复杂,比表面积较小,而飞灰中的碱性氯化物和金属化合物对酸洗处理过程中的浸出效率有明显影响。飞灰中的金属浸出效率与其性质和形态有关。水洗处理可造成飞灰中组成物质和化合物形态的变化,并显著去除飞灰中水溶性化合物如KCl、NaCl和CaCl2,对Cl、Na、K和Ca的去除率分别为93.1%、41.4%、48.5%和24.8%。酸灰比为40∶1(kg/L)、处理时间为120 min的酸洗处理可显著降低垃圾焚烧飞灰中Cu、Zn、Cd和Pb的毒性浸出浓度(80%−100%),在一定程度上降低As的毒性浸出浓度(30%−80%),但对Ni的脱除效果较差(< 30%)。而采用二次水洗+酸洗的组合处理工艺可进一步降低垃圾焚烧飞灰的环境风险。Abstract: The chemical and mineralogical characteristics of fly ash from a municipal solid waste incineration (MSWI) in China and the influence of processing parameters on heavy metals removal during leaching were investigated in this work. The fly ash particles had complex surface structure with limited specific surface area. The alkali chloride and metal salts in MSWI fly ash showed evidently impact on leaching efficiency. Metal leachability was related to their properties and speciation in fly ash. Water-soluble salts such as KCl, NaCl and CaCl2 in fly ash were easily washed out. In this study, removal efficiency by water washing was achieved to 93.1% for Cl, 41.4% for Na, 48.5% for K and 24.8% for Ca, respectively. Mineralogical analysis also revealed change of fly ash mineral phases and specification distribution after water washing. Under liquid to solid ratio of 40∶1 L/kg and treatment time of 120 min, the leaching process achieved high dropping yields of toxicity characteristic leaching procedure (TCLP) concentrations for Cu, Zn Cd and Pb (80%−100%), moderate dropping yields for As (30%−80%) and relatively low dropping yields of Ni (< 30%). In addition, heavy metals such as Pb and Zn in fly ash with twice water washing treatment at a low liquid-solid ratio could reach lower TCLP concentrations. The result indicated that the combination process of twice water washing and one acid washing could significantly reduce the environmental risk of MSWI fly ash.
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Key words:
- MSWI fly ash /
- characteristic /
- heavy metals removal /
- water-flushing pretreatment /
- chemical leaching
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Table 1 Main elements constitute of the RA and WA samples
Element RA w/% WA w/% O 37.62 39.98 Na 2.2 1.29 Si 4.35 6.54 S 1.88 2.38 Cl 10.78 0.74 K 2.27 1.17 Ca 36.82 27.68 Table 2 TCPL concentration of targeted metals detected in RA, LA and WLA samples by HJ/T300-2007
Item Regulatory levela Leaching concentration/(mg·L−1) RA LA WLA Be 0.02 0.01 NDb ND Cr 4.5 1.29 0.86 0.23 Ni 0.5 0.35 0.31 0.05 Cu 40 5.84 0.43 0.15 Zn 100 42.90 1.76 1.62 As 0.3 0.84 0.22 ND Cd 0.15 3.52 0.04 0.02 Pb 0.25 23.66 1.42 0.14 note: a: regulatory level refers to GB 16889-2008 of China; b: ND means not tested or lower level than the detectable limits of ICP-MS -
[1] PARK Y J, HEO J. Vitrification of fly ash from municipal solid waste incinerator[J]. J Hazard Mater,2002,91(1/3):83−93. doi: 10.1016/S0304-3894(01)00362-4 [2] EICEMAN G A, CLEMENT R E, KARASEK F W. Analysis of fly ash from municipal incinerators for trace organic compounds[J]. Anal Chem,1979,51(14):2343−2350. doi: 10.1021/ac50050a013 [3] WANG F H, ZHANG F, CHEN Y J, GAO J, ZHAO B. A comparative study on the heavy metal solidification/stabilization performance of four chemical solidifying agents in municipal solid waste incineration fly ash[J]. J Hazard Mater,2015,300:451−458. doi: 10.1016/j.jhazmat.2015.07.037 [4] CHOU S Y, LO S L, HSIEH C H, CHEN C L. Sintering of MSWI fly ash by microwave energy[J]. J Hazard Mater,2009,163(1):357−362. doi: 10.1016/j.jhazmat.2008.06.100 [5] LE FORESTIER L, LIBOUREL G. Characterization of flue gas residues from municipal solid waste combustors[J]. Environ Sci Technol,1998,32(15):2250−2256. doi: 10.1021/es980100t [6] SHIMAOKA T, HANASHIMA M. Behavior of stabilized fly ashes in solid waste landfills[J]. Waste Management,1996,16(5/6):545−554. doi: 10.1016/S0956-053X(96)00096-7 [7] PISCIELLA P, CRISUCCI S, KARAMANOV A, PELINO M. Chemical durability of glasses obtained by vitrification of industrial wastes[J]. Waste Management,2001,21(1):1−9. doi: 10.1016/S0956-053X(00)00077-5 [8] YOUCAI Z, LIJIE S, GUOJIAN L. Chemical stabilization of MSW incinerator fly ashes[J]. J Hazard Mater,2002,95(1):47−63. [9] BIE R, CHEN P, SONG X, JI X. Characteristics of municipal solid waste incineration fly ash with cement solidification treatment[J]. J Energy Inst,2016,89:704−712. doi: 10.1016/j.joei.2015.04.006 [10] CZOP M, ŁAŹNIEWSKA-PIEKARCZYK B. Evaluation of the leachability of contaminations of fly ash and bottom ash from the combustion of solid municipal waste before and after stabilization process[J]. Sustainability Basel,2019,11(19):5384. doi: 10.3390/su11195384 [11] ZHANG R, WEI X, HAO Q, SI R. Bioleaching of heavy metals from municipal solid waste incineration fly ash: Availability of recoverable sulfur prills and form transformation of heavy metals[J]. Metals,2020,10(6):815. doi: 10.3390/met10060815 [12] CHEN W S, CHANG F C, SHEN Y H, TSAI M S, KO C H. Removal of chloride from MSWI fly ash[J]. J Hazard Mater,2012,237−238:116−120. doi: 10.1016/j.jhazmat.2012.08.010 [13] SHI H S, KAN L L. Leaching behavior of heavy metals from municipal solid wastes incineration (MSWI) fly ash used in concrete[J]. J Hazard Mater,2009,164(2/3):750−754. doi: 10.1016/j.jhazmat.2008.08.077 [14] SAQIB N, BÄCKSTRÖM M. Chemical association and mobility of trace elements in 13 different fuel incineration fly ashes[J]. Fuel,2016,165:193−204. doi: 10.1016/j.fuel.2015.10.062 [15] FUNARI V, MÄKINEN J, SALMINEN J, BRAGA R, DINELLI E, REVITZER H. Metal removal from Municipal Solid Waste Incineration fly ash: A comparison between chemical leaching and bioleaching[J]. Waste Management,2016,60:397. [16] WEIBEL G, EGGENBERGER U, SCHLUMBERGER S, MÄDER U K. Chemical associations and mobilization of heavy metals in fly ash from municipal solid waste incineration[J]. Waste Management,2017,62:147−159. doi: 10.1016/j.wasman.2016.12.004 [17] RAMANATHAN T, TING Y P. Alkaline bioleaching of municipal solid waste incineration fly ash by autochthonous extremophiles[J]. Chemosphere,2016,160:54−61. doi: 10.1016/j.chemosphere.2016.06.055 [18] NI P, XIONG Z, TIAN C, LI H, ZHAO Y, ZHANG J, ZHENG C. Influence of carbonation under oxy-fuel combustion flue gas on the leachability of heavy metals in MSWI fly ash[J]. Waste Management,2017,67:171−180. doi: 10.1016/j.wasman.2017.05.023 [19] ZHOU J, WU S, PAN Y, ZHANG L, CAO Z, ZHANG X, QIAN G. Enrichment of heavy metals in fine particles of municipal solid waste incinerator (MSWI) fly ash and associated health risk[J]. Waste Management,2015,43(SEP):239−246. [20] TANG P, FLOREA M V A, SPIESZ P, BROUWERS H J H. Application of thermally activated municipal solid waste incineration (MSWI) bottom ash fines as binder substitute[J]. Cem Concr Compos,2016,70:194−205. doi: 10.1016/j.cemconcomp.2016.03.015 [21] WU H Y, TING Y P. Metal extraction from municipal solid waste (MSW) incinerator fly ash—Chemical leaching and fungal bioleaching[J]. Enzyme Microb Technol,2006,38(6):839−847. doi: 10.1016/j.enzmictec.2005.08.012 [22] GONG Y, KIRK D W. Behaviour of municipal solid waste incinerator fly ash: I: General leaching study[J]. J Hazard Mater,1994,36(3):249−264. doi: 10.1016/0304-3894(94)85018-6 [23] FERMO P, CARIATI F, POZZI A, DEMARTIN F, TETTAMANTI M, COLLINA E, RUSSO U. The analytical characterization of municipal solid waste incinerator fly ash: Methods and preliminary results[J]. Fresenius J Anal Chem,1999,365(8):666−673. doi: 10.1007/s002160051543 [24] AZAM M, SETOODEH JAHROMY S, RAZA W, WESENAUER F, SCHWENDTNER K, WINTER F. Comparison of the characteristics of fly ash generated from bio and municipal waste: fluidized bed incinerators[J]. Materials,2019,12(17):2664. doi: 10.3390/ma12172664 [25] SHI D, HU C, ZHANG J, LI P, ZHANG C, WANG X, MA H. Silicon-aluminum additives assisted hydrothermal process for stabilization of heavy metals in fly ash from MSW incineration[J]. Fuel Process Technol,2017,165:44−53. doi: 10.1016/j.fuproc.2017.05.007 [26] HUANG K, INOUE K, HARADA H, KAWAKITA H, KEISUKE O H T O. Leaching behavior of heavy metals with hydrochloric acid from fly ash generated in municipal waste incineration plants[J]. Trans Nonferrous Met Soc China,2011,21(6):1422−1427. doi: 10.1016/S1003-6326(11)60876-5 [27] ZHAO S, CHEN Z, SHEN J, KANG J, ZHANG J, SHEN Y. Leaching mechanisms of constituents from fly ash under the influence of humic acid[J]. J Hazard Mater,2017,321:647−660. doi: 10.1016/j.jhazmat.2016.09.054 [28] CHEN P, ZHENG H, XU H, GAO Y X, DING X Q, MA M L. Microbial induced solidification and stabilization of municipal solid waste incineration fly ash with high alkalinity and heavy metal toxicity[J]. PLoS One,2019,14(10):e0223900. doi: 10.1371/journal.pone.0223900 [29] KRUK M, JARONIEC M. Gas adsorption characterization of ordered organic-inorganic nanocomposite materials[J]. Chem Mater,2001,13(10):3169−3183. doi: 10.1021/cm0101069 [30] YAKOUT S M, EL-DEEN G S. Characterization of activated carbon prepared by phosphoric acid activation of olive stones[J]. Arab J Chem, 2011, 9(40): S1155–S1162. [31] KANOKWAN K, BORA C, AHMET H A, CRAIG H B, TUNCER B E. Effects of pH on the leaching mechanisms of elements from fly ash mixed soils[J]. Fuel,2015,140:788−802. [32] IZQUIERDO M, QUEROL X. Leaching behaviour of elements from coal combustion fly ash: An overview[J]. Int J Coal Geol,2012,94:54−66. doi: 10.1016/j.coal.2011.10.006 [33] ZHANG Y, CETIN B, LIKOS W J, EDIL T B. Impacts of pH on leaching potential of elements from MSW incineration fly ash[J]. Fuel,2016,184:815−825. doi: 10.1016/j.fuel.2016.07.089 [34] HAN C, LI H, YAN Y, YU L, LIN H, HUANG X, LI D. Effect of different pretreatment solutions on electrokinetic remediation of heavy metals from municipal solid waste incineration fly ash[J]. Int J Electrochem Sci,2020,15:8694−8709. [35] NAGIB S., INOUE K. Recovery of lead and zinc from fly ash generated from municipal incineration plants by means of acid and/or alkaline leaching[J]. Hydrometallurgy,2000,56(3):269. doi: 10.1016/S0304-386X(00)00073-6 [36] LIU F, LIU J, YU Q, JIN Y, NIE Y. Leaching characteristics of heavy metals in municipal solid waste incinerator fly ash[J]. J Environ Sci Health,2005,40(10):1975−1985. doi: 10.1080/10934520500184707