本文關(guān)鍵詞： 水熱法 活垃圾 飛灰 重金屬 雪硅鈣石 晶種　出處：《重慶大學(xué)》2016年碩士論文　論文類型：學(xué)位論文

【摘要】：近年來我國生活垃圾焚燒處理量快速增長,垃圾焚燒過程中產(chǎn)生了大量焚燒飛灰。飛灰因含有重金屬、二VA英等污染物,被國家列為危險(xiǎn)廢棄物,需要進(jìn)行無害化處理。近年來國內(nèi)外學(xué)者對(duì)飛灰中重金屬的穩(wěn)定化進(jìn)行了大量的研究。但是目前的重金屬穩(wěn)定化方法存在二次污染高、設(shè)備昂貴、能耗高等問題。針對(duì)這些問題,本文依托重慶市前沿與應(yīng)用基礎(chǔ)研究項(xiàng)目(CSTC2014jcyjA20015),開展了針對(duì)垃圾焚燒飛灰中重金屬穩(wěn)定化的實(shí)驗(yàn)和理論研究。本研究的主要內(nèi)容及結(jié)論如下:(1)針對(duì)爐排爐飛灰硅鋁含量較低的特點(diǎn),采用粉煤灰、膨潤土、高嶺土為硅鋁調(diào)理劑,開展了硅鋁添加下水熱穩(wěn)定生活垃圾焚燒飛灰重金屬的研究。結(jié)果表明,在飛灰水熱處理中添加粉煤灰、膨潤土、高嶺土均合成了雪硅鈣石等對(duì)重金屬具有穩(wěn)定效果的沸石類晶體。水熱條件下分別添加三種硅鋁調(diào)理劑使飛灰水熱產(chǎn)物重金屬浸出毒性顯著降低,遠(yuǎn)遠(yuǎn)低于危廢鑒別標(biāo)準(zhǔn),并可以抑制水熱反應(yīng)過程中Pb、Zn向液相中的轉(zhuǎn)移,但三種調(diào)理劑在水熱條件下穩(wěn)定飛灰中重金屬的效果沒有顯著差異。同時(shí)發(fā)現(xiàn)高溫有利于雪硅鈣石的合成,但會(huì)導(dǎo)致Pb、Zn等重金屬向水熱反應(yīng)液相中的轉(zhuǎn)移量增大。此外修正的BCR多步連續(xù)提取的實(shí)驗(yàn)結(jié)果表明,水熱產(chǎn)物中重金屬Pb向更穩(wěn)定的形態(tài)轉(zhuǎn)化。(2)采用水熱法合成雪硅鈣石晶體并對(duì)其重金屬吸附能力進(jìn)行了表征。結(jié)果表明:采用二氧化硅,氫氧化鋁,碳酸鈣,氫氧化鈉,去離子水為原料,在150℃下成功合成了雪硅鈣石晶體,且反應(yīng)時(shí)間為8d時(shí)雪硅石晶體純度較高。雪硅鈣石晶體對(duì)Pb2+、Zn2+、Cu2+、Cd2+、Cr3+吸附量分別達(dá)到了141.41mg/g、59.75 mg/g、43.09mg/g、46.08mg/g、20.10mg/g,同時(shí)浸出毒性測試結(jié)果表明被吸附后的重金屬具有很好的穩(wěn)定性。但當(dāng)重金屬溶液中含有多種重金屬時(shí),雪硅鈣石對(duì)Cd2+吸附量顯著下降。(3)進(jìn)一步開展了硅鋁添加及晶種誘導(dǎo)下水熱穩(wěn)定飛灰重金屬的研究。結(jié)果表明:在飛灰水熱處理中混合添加15%粉煤灰和15%硅藻土作為硅鋁調(diào)理劑,200℃下雪硅鈣石的生成量明顯高于單一添加30%的粉煤灰,并且明顯抑制了水鈣鋁榴石的生成,這表明混合添加粉煤灰和硅藻土?xí)r反應(yīng)體系中的元素組成更適合雪硅鈣石的生成;在反應(yīng)體系中加入3%的雪硅鈣石晶種后,200℃下雪硅鈣石的出峰時(shí)間提前6個(gè)小時(shí);150℃下添加3%雪硅鈣石晶種成功誘導(dǎo)合成了雪硅鈣石,并抑制了水鋁鈣石的生成,這表明晶種添加可以加速雪硅鈣石的生成,并能提高對(duì)原料的適應(yīng)性,還可以抑制雜晶的生成。晶種的添加顯著降低了水熱產(chǎn)物中重金屬Pb和Zn的浸出濃度,并可以顯著加速飛灰中Pb和Zn的穩(wěn)定�？傊�,在水熱法穩(wěn)定飛灰重金屬的過程中,采用硅鋁添加和晶種誘導(dǎo)可以顯著提高飛灰重金屬的穩(wěn)定效果,降低反應(yīng)溫度,縮短反應(yīng)時(shí)間,達(dá)到了提高穩(wěn)定效果、降低能耗的目的,具有工業(yè)化應(yīng)用的前景。
[Abstract]:In recent years, the incineration capacity of domestic solid waste (MSW) in China has increased rapidly, and a large number of fly ash has been produced in the process of MSW incineration. The fly ash has been classified as hazardous waste by the country because of its heavy metal, diVA and other pollutants. In recent years, scholars at home and abroad have done a lot of research on the stabilization of heavy metals in fly ash. However, the current methods of heavy metal stabilization have high secondary pollution and expensive equipment. Problems such as high energy consumption. Based on CSTC2014jcyjA2001515, an experimental and theoretical study on the stabilization of heavy metals in fly ash from MSW incineration was carried out in this paper. The main contents and conclusions of this study are as follows: 1) aiming at the low content of Si-Al in fly ash of grate furnace. Using fly ash, bentonite and kaolin as silane and aluminum conditioning agent, the heavy metal in fly ash of solid waste incineration was studied by adding silica and aluminum into water heat treatment. The results showed that the addition of fly ash and bentonite in hydrothermal treatment of fly ash, bentonite, etc. Zeolites with stable effect on heavy metals have been synthesized from kaolinite. Under hydrothermal conditions, the leaching toxicity of heavy metals in hydrothermal products of fly ash is significantly reduced by adding three kinds of silicon-aluminum conditioning agents, which is far lower than the identification standard for hazardous wastes. It also inhibited the transfer of PBN Zn to liquid phase during hydrothermal reaction, but there was no significant difference between the three conditioners in stabilizing heavy metals in fly ash under hydrothermal conditions. At the same time, it was found that high temperature was beneficial to the synthesis of snow silicalite. However, the transfer amount of heavy metals such as Pb, Zn and other heavy metals into the hydrothermal reaction liquid phase will be increased. In addition, the experimental results of modified multi-step continuous extraction of BCR show that, The heavy metal Pb in hydrothermal products was transformed into a more stable form. The crystal was synthesized by hydrothermal method and its adsorption capacity of heavy metals was characterized. The results showed that silica, aluminum hydroxide, calcium carbonate, sodium hydroxide were used. The silica crystals were successfully synthesized from deionized water at 150 鈩，

本文編號(hào)：1550878