Stabilization of heavy metals in municipal solid waste incineration fly ash using thermal treatment with silica-based material

doi:10.16085/j.issn.1000-6613.2017-0141

Abstract

Abstract: Heat treatments were performed with municipal solid waste incineration fly ash(MSWI FA),mixing with silica fume,colloidal silica,quartz sand respectively and a certain proportion of water. The effects of additive species,thermal treatment temperature on the leaching of critical heavy metals(Pb,Cd and Cr) were studied. The changes of chemical speciation of heavy metals,crystal structure and microstructure during heat treatment were also investigated. The results showed that silica fume and colloidal silica react with calcium-based materials in fly ash to form silicate phases such as CaSiO₃、Ca₂SiO₄、Ca₃SiO₄Cl₂、Ca₃Fe₂(SiO₄)₃ and hydroxyl-ellestadite during the heat treatment,changing the chemical speciation of heavy metals and stabilizing heavy metals in the silicate lattice,which reduces the leaching toxicity. The leaching concentration of Pb in fly ash decreased from 11.91mg/L to 0.79mg/L and 0.78mg/L,respectively,under the conditions of adding 10% silica fume or 25% JN-40 colloidal silica and heat treatment at 600℃ for one hour,while the leaching concentration of Cd decreased from 3.18mg/L to 0.09mg/L and 0.10mg/L,respectively. During the heat treatment,the leaching concentration of Cr increased but did not exceed the standard for pollution control on the landfill site of municipal solid waste.

Key words: municipal solid waste incineration, fly ash, thermal treatment, heavy metals, stabilization and solidification

摘要： 向垃圾焚烧飞灰（MSWI FA）中分别添加硅灰、硅溶胶、石英砂与一定比例的水，混合均匀并进行热处理。研究了添加物种类、热处理温度对垃圾焚烧飞灰中重金属浸出特性的影响，分析了飞灰热处理过程中重金属化学形态、晶体结构和微观形貌的变化。结果表明：热处理过程中，硅灰和硅胶与飞灰中的钙基物质反应生成CaSiO₃、Ca₂SiO₄、Ca₃SiO₄Cl₂、Ca₃Fe₂（SiO₄）₃以及氢氧硅磷灰石等硅酸盐相，转变了重金属的化学形态，将重金属稳固在硅酸盐晶格中，降低了飞灰的浸出毒性；在硅灰添加量为10%或JN-40硅胶添加量25%，热处理温度600℃条件下，热处理1h后，飞灰中Pb的浸出浓度由11.91mg/L分别降至0.79mg/L和0.78mg/L，Cd的浸出浓度由3.18mg/L分别降至0.09mg/L和0.10mg/L；热处理过程中Cr的浸出浓度有所上升但未超出生活垃圾填埋场控制标准。

关键词: 垃圾焚烧, 飞灰, 热处理, 重金属, 稳固化

CLC Number:

X705

SUN Li, WU Xin, LIU Daojie, LI Junhui, LI Shi, DU Yiwei. Stabilization of heavy metals in municipal solid waste incineration fly ash using thermal treatment with silica-based material[J]. Chemical Industry and Engineering Progress, 2017, 36(09): 3514-3522.

孙立, 吴新, 刘道洁, 李军辉, 李诗, 都艺伟. 基于硅基的垃圾焚烧飞灰中温热处理重金属稳固化实验[J]. 化工进展, 2017, 36(09): 3514-3522.

References

[1] 熊祖鸿,范根育,鲁敏,等. 垃圾焚烧飞灰处置技术研究进展[J]. 化工进展,2013,32(7):1678-1684. XIONG Z H,FAN G Y,LU M,et al. Treatment technologies of municipal solid waste incinerator fly ash:a review[J]. Chemical Industry and Engineering Progress,2013,32(7):1678-1684.
[2] BONTEMPI E,ZACCO A,BORGESE L,et al. A new powder filler,obtained by applying a new technology for fly ash inertisation procedure[C]//Advances in Science and Technology. Trans. Tech. Publications,2010,62:27-33.
[3] BENASSI L,BOSIO A,DALIPI R,et al. Comparison between rice husk ash grown in different regions for stabilizing fly ash from a solid waste incinerator[J]. Journal of Environmental Management,2015,159:128-134.
[4] BOSIO A,RODELLA N,GIANONCELLI A,et al. A new method to inertize incinerator toxic fly ash with silica from rice husk ash[J]. Environmental Chemistry Letters,2013,11(4):329-333.
[5] BOSIO A,GIANONCELLI A,ZACCO A,et al. A new nanotechnology of fly ash inertization based on the use of silica gel extracted from rice husk ash and microwave treatment[J]. Proceedings of the Institution of Mechanical Engineers Part N:Journal of Nanoengineering and Nanosystems,2014,228(1):27-32.
[6] BOSIO A,BONTEMPI E,RODELLA N,et al. Rice husk ash based composites,obtained by toxic fly ash inertization,and their applications as adsorbents[J]. Chemical Engineering Transactions,2014,37:631-636.
[7] LI X,CHEN Q,ZHOU Y,et al. Stabilization of heavy metals in MSWI fly ash using silica fume[J]. Waste Management,2014,34(12):2494-504.
[8] RODELLA N,BOSIO A,ZACCO A,et al. Arsenic stabilization in coal fly ash through the employment of waste materials[J]. Journal of Environmental Chemical Engineering,2014,2(3):1352-1357.
[9] 田书磊. 垃圾焚烧飞灰重金属热分离工艺及挥发特性研究[D]. 哈尔滨:哈尔滨工业大学,2007. TIAN S L. Thermal separation process and evaporation mechanism of heavy metal from MSWI fly ash[D]. Harbin:Harbin Institute of Technology,2007.
[10] 邓燚超. 垃圾焚烧飞灰低中温热处理过程中氯及重金属的迁徙特性分析[D]. 杭州:浙江大学,2007. DENG Y. Analysis the transferring characteristics of the chlorine and heavy metals of the MSWI fly ash in low and medium temperature heat treatment[D]. Hangzhou:Zhejiang University,2007.
[11] MENARD Y,ASTHANA A,PATISSON F,et al. Thermodynamic study of heavy metals behaviour during municipal waste incineration[J]. Process Safety & Environmental Protection,2006,84(4):290-296.
[12] 罗春晖. 生活垃圾焚烧飞灰水洗-稳定化试验研究[D]. 上海:东华大学,2003. LUO C H. Study on water-immobilization process of MSWI fly ash[D]. Shanghai:Donghua University,2003.
[13] 蔵本,康宏,高岡,昌輝,武田,信生. 飛灰中重金属の形態同定に関する研究(京都大学環境衛生工学研究会第19回シンポジウム講演論文集(1997年7月24日·25日,京都))——(一般講演)[J]. 環境衛生工学研究,1997,11(3):53-58.
[14] UMOREN I U,UDOH A P,UDOUSORO I I. Concentration and chemical speciation for the determination of Cu,Zn,Ni,Pb and Cd from refuse dump soils using the optimized BCR sequential extraction procedure[J]. Environment Systems and Decisions,2007,27(2):241-252.
[15] WU S,XU Y,SUN J,et al. Inhibiting evaporation of heavy metal by controlling its chemical speciation in MSWI fly ash[J]. Fuel,2015,158:764-769.
[16] ZHANG H,ZHAO Y,QI J. Thermal characterization of fly ash from one municipal solid waste incinerator (MSWI)in Shanghai[J]. Process Safety and Environmental Protection,2010,88:269-275.
[17] PARK Y J,HEO J. Vitrification of fly ash from municipal solid waste incinerator.[J]. Journal of Hazardous Materials,2002,91(1/2/3):83-93.
[18] KUO Y M,WANG J W,WANG C T,et al. Effect of water quenching and SiO₂ addition during vitrification of fly ash. Part 1:On the crystalline characteristics of slags[J]. Journal of Hazardous Materials,2008,152(3):994-1001.
[19] JAKOB A,STUCKI S,STRUIS R P W J. Complete heavy metal removal from fly ash by heat treatment:influence of chlorides on evaporation rates[J]. Environmental Science & Technology,1996,30(11):3275-3283.
[20] ZHANG H Y,ZHAO Y C,QI J Y. Measurement of composition variation of municipal solid waste incineration(MSWI) fly ash during thermal treatment[J]. Key Engineering Materials,2011,460-461:90-95.
[21] HU H,LUO G,LIU H,et al. Fate of chromium during thermal treatment of municipal solid waste incineration(MSWI)fly ash[J]. Proceedings of the Combustion Institute,2013,34(2):2795-2801.
[22] HU H,LIU H,SHEN W Q,et al. Comparison of CaO's effect on the fate of heavy metals during thermal treatment of two typical types of MSWI fly ashes in China[J]. Chemosphere,2013,93(4):590-596.
[23] KIRK D W,CHAN C C,MARSH H. Chromium behavior during thermal treatment of MSW fly ash[J]. Journal of Hazardous Materials,2002,90(1):39-49.
[24] LEE Y M,NASSARALLA C L. Standard free energy of formation of calcium chromate[J]. Materials Science and Engineering A,2006,437(2):334-339.
[25] WANG K S,SUN C J,LIU C Y. Effects of the type of sintering atmosphere on the chromium leachability of thermal-treated municipal solid waste incinerator fly ash[J]. Waste Management,2001,21(1):85-91.
[26] HU H Y,LIU H,ZHANG Q,et al. Sintering characteristics of CaO-rich municipal solid waste incineration fly ash through the addition of Si/Al-rich ash residues[J]. Journal of Material Cycles and Waste Management,2016,18(2):340-347.