本文關(guān)鍵詞： 分段水熱法 堿溶預(yù)處理 城市生活垃圾焚燒飛灰 重金屬　出處：《華中科技大學(xué)》2015年碩士論文　論文類型：學(xué)位論文

【摘要】：焚燒法因其工藝簡單可靠、減容量大和能源回收等顯著優(yōu)點逐漸成為處理城市生活垃圾的主要方法之一。然而垃圾焚燒產(chǎn)生的飛灰由于含有較高濃度重金屬及二VA英等污染物而被公認(rèn)為危險廢物需要進一步處理。針對目前新興的水熱法處理垃圾焚燒飛灰過程中產(chǎn)生含有較高濃度鉛、鋅等重金屬的殘液需要處理并且在合成過程中會產(chǎn)生再吸附等問題,本文以流化床垃圾焚燒爐產(chǎn)生的飛灰為研究對象,通過添加堿溶預(yù)處理步驟,實現(xiàn)了分段水熱處理垃圾焚燒飛灰工藝,以期更好的穩(wěn)定其中的重金屬。1.研究了四種固體廢物浸出方法對城市生活垃圾焚燒飛灰重金屬浸出結(jié)果的影響。結(jié)果表明:采用醋酸緩沖液作為浸提劑的HJ/T 300方法和TCLP方法,鉛和鋅的浸出量較高;由于垃圾焚燒飛灰自身具有高堿性,采用硫酸/硝酸混合液作為浸提劑的HJ/T 299方法因不具備緩沖能力,鉛和鋅的浸出量最低,反而采用中性去離子水作為浸提劑的HJ 577方法較HJ/T 299方法鉛和鋅的浸出量還要略高。2.開展了水熱法處理垃圾焚燒飛灰的主要影響因素的實驗研究,結(jié)果表明:垃圾焚燒飛灰在一定的NaOH濃度和反應(yīng)溫度條件下經(jīng)過水熱反應(yīng)生成了諸如加藤石(Katoite)、雪硅鈣石(Tobermorite)和方納石(Sodalite)等類沸石礦物,同時使得合成產(chǎn)物的浸出毒性有效降低,但當(dāng)NaOH濃度超過3 mol/L時僅有方納石(Sodalite)生成,說明過量的堿度反而會阻礙水熱反應(yīng)的結(jié)晶過程,當(dāng)反應(yīng)溫度140℃時,合成產(chǎn)物的浸出毒性反而會上升,說明過高的反應(yīng)溫度會使水熱合成產(chǎn)物穩(wěn)定重金屬的效果降低。最終確定最優(yōu)的反應(yīng)條件為NaOH濃度1 mol/L、反應(yīng)溫度120℃。3.通過堿溶預(yù)處理步驟的添加,改進了水熱法穩(wěn)定垃圾焚燒飛灰的處理工藝。探討了堿溶預(yù)處理過程溶出鉛、鋅的最優(yōu)條件為反應(yīng)溫度為70℃、反應(yīng)時間為50分鐘、堿濃度為4 mol/L。并對合成產(chǎn)物進行浸出毒性分析,結(jié)果表明:分段水熱法能更加有效的穩(wěn)定垃圾焚燒飛灰中重金屬,并減少合成產(chǎn)物及殘液的二次污染風(fēng)險。
[Abstract]:The incineration process is simple and reliable. Large capacity reduction and energy recovery have gradually become one of the main methods for the treatment of municipal solid waste. However, fly ash from incineration is recognized as dangerous because of its high concentration of heavy metals and other pollutants such as diVA. Hazardous wastes need further treatment. High concentrations of lead are produced during the treatment of waste incineration fly ash by new and emerging hydrothermal processes, Zinc and other heavy metal residues need to be treated and readsorbed in the process of synthesis. In this paper, fly ash produced by fluidized bed incinerator is taken as the research object. The process of incineration fly ash by subsection hydrothermal treatment is realized. The effects of four solid waste leaching methods on the heavy metal leaching of municipal solid waste incineration fly ash were studied. The results showed that the HJ/T 300 and TCLP methods were used as extractant to extract the heavy metals from municipal solid waste incineration fly ash. The leaching amount of lead and zinc is high, and the leaching amount of lead and zinc is the lowest because the HJ/T 299 method which uses sulfuric acid / nitric acid mixture as extractant has no buffer capacity, because of the high alkalinity of waste incineration fly ash. On the contrary, HJ577, which uses neutral deionized water as extractant, is slightly higher than HJ/T 299 in the leaching of lead and zinc. The experimental study on the main factors affecting the treatment of waste incineration fly ash by hydrothermal method is carried out. The results show that under certain NaOH concentration and reaction temperature, waste incineration fly ash produces zeolite-like minerals such as Katoite, Tobermorite and Sodalite, which can effectively reduce the leaching toxicity of the synthesized products. However, when the concentration of NaOH is more than 3 mol/L, only mononalite is formed, which indicates that excessive alkalinity will hinder the crystallization process of hydrothermal reaction, and the leaching toxicity of the synthesized product will increase when the reaction temperature is 140 鈩，

本文編號：1494575