【摘要】：脫硫石膏是燃煤煙氣鈣法脫硫產(chǎn)生的大宗工業(yè)副產(chǎn)物,其資源化利用是提升煙氣脫硫工業(yè)的關(guān)鍵環(huán)節(jié)之一,但應(yīng)用過程中的環(huán)境相容性是亟需關(guān)注的問題。本論文采用生態(tài)模式方法對(duì)脫硫石膏中的雜質(zhì)組分及重金屬組分的分布和遷移規(guī)律進(jìn)行了研究,評(píng)價(jià)脫硫石膏與環(huán)境的相容性,為脫硫石膏安全的資源化應(yīng)用提供基礎(chǔ)數(shù)據(jù)。研究中采用了武漢和浙江兩個(gè)電廠的脫硫石膏,分別標(biāo)識(shí)為FA1和FA2。淋濾模式法采用柱淋濾和批淋濾兩種方式研究脫硫石膏中重金屬Cr、As、Ni、Pb組分的遷移規(guī)律,分別模擬了大氣降水和地表水浸泡兩種環(huán)境,同時(shí)還采用標(biāo)準(zhǔn)Tessier法,分析脫硫石膏中重金屬組分的賦存形態(tài)。賦存形態(tài)分析結(jié)果表明重金屬組分主要以可遷移組分為主,而能穩(wěn)定存在的殘?jiān)鼞B(tài)所占比例最低;不同電廠的脫硫石膏中重金屬組分賦存形態(tài)比例存在差別,因此其組分的遷移特性也不同。研究中采用兩種電廠石膏,主要考慮淋濾時(shí)間和淋濾液pH值兩個(gè)主要過程條件。實(shí)驗(yàn)結(jié)果表明脫硫石膏中重金屬的淋出過程受到賦存形態(tài)、淋濾時(shí)間和淋濾液pH等因素共同影響,長(zhǎng)淋濾時(shí)間和低淋濾液pH值會(huì)促使4種重金屬組分從脫硫石膏中遷移出來。FA1的淋濾結(jié)果表明,批淋濾中重金屬組分淋出率順序?yàn)镻bCrNiAs,柱淋濾中則為PbAsCrNi;FA2的淋濾結(jié)果表明,批淋慮中重金屬淋出率順序?yàn)镃rNiAsPb,柱淋濾中則為AsPbNiCr。因此通過淋濾可致脫硫石膏中重金屬組分產(chǎn)生遷移,且大部分淋濾液中重金屬含量超過國(guó)家標(biāo)準(zhǔn),因此脫硫石膏對(duì)水環(huán)境而言存在風(fēng)險(xiǎn)。熱誘導(dǎo)脫附方法研究脫硫石膏制品中汞及其化合物在氮?dú)鈿夥障碌囊莩鲆?guī)律,采用安大略水法吸收熱解析的汞化合物,原子熒光法定量分析不同溫度段析出的汞化合物。研究表明脫硫石膏中汞系物主要釋放溫度范圍是250~450℃及650~850℃,兩種脫硫石膏中Hg~(2+)的析出變化規(guī)律基本一致,Hg~(2+)的含量均是隨著溫度的升高呈現(xiàn)先增加再減少再增加的趨勢(shì);250~450℃溫度段,Hg~0的釋放均達(dá)到最大值。因此煅燒加工脫硫石膏過程中,特別高溫煅燒過程汞系物存在二次釋放的隱患。返霜實(shí)驗(yàn)通過探討不同養(yǎng)護(hù)條件下石膏砌塊的滲透方式,探索Na和Mg組分在脫硫石膏砌塊中的分布規(guī)律的變化。Na、Mg組分引起的返霜現(xiàn)象是脫硫石膏應(yīng)用過程中的主要缺陷之一,是Na~+、Mg~(2+)等離子遷移到石膏砌塊表面所致。研究過程主要考慮了養(yǎng)護(hù)方式、可溶性鹽含量、水膏比三個(gè)關(guān)鍵因素,結(jié)果表明可溶性鹽含量較高、水膏比較低時(shí),返霜現(xiàn)象將會(huì)加劇;可溶性鹽遷移規(guī)律是優(yōu)先在棱邊結(jié)晶,這是因?yàn)榭扇苄喳}在潮濕環(huán)境中隨水分蒸發(fā)作用被帶到砌塊表面沉淀析出所致。研究表明,脫硫石膏中雜質(zhì)組分及重金屬組分與環(huán)境之間存在交換、遷移和釋放的過程,脫硫石膏在加工以及存放于環(huán)境中所交換、遷移和釋放的雜質(zhì)組分,特別是重金屬組分對(duì)局部環(huán)境產(chǎn)生微污染,且長(zhǎng)期的累積效應(yīng)不容忽視。
[Abstract]:Desulphurization gypsum is a major industrial by-product produced by calcium desulphurization in coal-fired flue gas, and its resource utilization is one of the key links in the promotion of flue gas desulfurization industry, but environmental compatibility in the application process is an urgent problem. This paper uses the ecological model method to distribute and move the impurity components and heavy metal components in the desulphurized gypsum. The compatibility of desulphurized gypsum with the environment is evaluated to provide basic data for the application of desulphurized gypsum to safety resources. The desulphurizing gypsum in two power plants in Wuhan and Zhejiang is used in the study. The FA1 and FA2. leaching mode method is used to study the heavy metal Cr and As in the desulphurizing gypsum by column leaching and batch leaching. The migration law of Ni and Pb components, respectively simulated the two environment of atmospheric precipitation and surface water immersion, and also used the standard Tessier method to analyze the occurrence form of heavy metal components in the desulphurization gypsum. The proportion of heavy metal components in the desulphurized gypsum in the same power plant is different, so the migration characteristics of the components are also different. In the study, two kinds of power plant gypsum are used, mainly considering the two main process conditions for the leaching time and the pH value of the leachate. The experimental results show that the leaching process of heavy metals in the desulphurizing gypsum is subjected to the occurrence form and the leaching process. Among the factors such as pH and other factors, the long leaching time and the pH value of the filtrate will promote the leaching of 4 heavy metal components from the desulphurized gypsum. The leaching rate of the heavy metal components in the batch leaching is PbCrNiAs and the column leaching is PbAsCrNi; the leaching results of FA2 show that the leaching rate of heavy metals in batch leaching is smooth. The sequence is CrNiAsPb, and the column leaching is AsPbNiCr. so that the heavy metal components in the desulphurizing gypsum can be migrated by leaching, and the heavy metal content in most of the filtrate is more than the national standard. Therefore, the desulfurization gypsum has a risk for the water environment. The Ontario water method is used to absorb the Hg compounds analyzed by the Ontario water method, and the atomic fluorescence spectrometry is used to quantitatively analyze the precipitated mercury compounds in different temperatures. The study shows that the main release temperature range of the mercury Series in the desulphurization gypsum is 250~450 and 650~850, and the precipitation of Hg~ (2+) in the two kinds of desulphurized gypsum is basically the same, Hg~ (2+) is contained in the gypsum. At 250~450 C, the release of Hg~0 reached the maximum. Therefore, in the process of calcining, the hidden danger of the two release of mercury in the special high temperature calcination process was found. The back frost experiment was carried out to explore the permeation mode of gypsum block under different curing conditions. The change of the distribution law of Na and Mg components in the desulphurized gypsum block is.Na, and the return frost caused by the Mg component is one of the main defects in the application of the gypsum gypsum. It is caused by the migration of Na~+ and Mg~ (2+) plasma to the gypsum block surface. The study process mainly considers the three key factors of the curing mode, the soluble salt content and the water paste ratio. The results show that the content of soluble salt is higher, and the phenomenon of back frost will be aggravated when the water paste is low. The migration law of soluble salt is preceded by the edge crystal, which is due to the precipitation of soluble salt in the wet environment with the evaporation of water to the surface of the block. In the process of exchange, migration and release, the impurity components in the process of processing and storage in the environment, the migration and release of impurities, especially the heavy metal components, produce micro pollution to the local environment, and the long-term cumulative effect can not be ignored.
【學(xué)位授予單位】：武漢科技大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2016
【分類號(hào)】：TQ177.3

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本文編號(hào)：2159602