本文關(guān)鍵詞：循環(huán)流化床鍋爐固硫灰制備混凝土膨脹劑的材料組成設(shè)計(jì)及性能研究　出處：《華南理工大學(xué)》2013年碩士論文　論文類(lèi)型：學(xué)位論文

  更多相關(guān)文章： CFB固硫灰 復(fù)合膨脹劑 原料性狀 膨脹劑組成設(shè)計(jì) 膨脹特性

【摘要】：循環(huán)流化床(CFB)鍋爐燃燒已成為我國(guó)大力發(fā)展的清潔燃煤發(fā)電技術(shù)，其脫硫產(chǎn)物循環(huán)流化床鍋爐固硫灰(以下簡(jiǎn)稱CFB固硫灰)排放量比普通燃煤方式高，且其組成、結(jié)構(gòu)有別于粉煤灰，若按粉煤灰使用可能產(chǎn)生較大危害，故CFB固硫灰作為一種新的大宗工業(yè)固體廢棄物，其資源化利用成為亟待解決的難題。根據(jù)CFB固硫灰含有f-CaO、CaSO4和活性Al2O3等制備氧化鈣-硫鋁酸鈣復(fù)合膨脹劑的組分，本論文提出用其制備混凝土膨脹劑，對(duì)于實(shí)現(xiàn)CFB固硫灰的資源化利用，減少環(huán)境污染，具有重要的意義。 本論文首先研究了利用CFB固硫灰與煅燒氧化鈣、石膏配制混凝土復(fù)合膨脹劑，探究膨脹劑中原料性狀及含量對(duì)膨脹劑性能的影響規(guī)律。結(jié)果表明，不同溫度煅燒的氧化鈣、膨脹劑的組成都會(huì)對(duì)膨脹性能產(chǎn)生顯著影響，石膏類(lèi)型對(duì)膨脹性能的影響甚微。1400°C煅燒的氧化鈣最適宜配制復(fù)合膨脹劑，含量為20%-30%時(shí)適宜配制性能滿足標(biāo)準(zhǔn)的復(fù)合膨脹劑；煅燒氧化鈣含量一定時(shí)，固硫灰與石膏含量比變化會(huì)影響鈣礬石的生成量，當(dāng)膨脹劑組成中nSO3/nAl2O3≈3時(shí)能生成最多的鈣礬石，膨脹率最大。固硫灰在復(fù)合膨脹劑中起到提供膨脹源反應(yīng)物及部分膨脹源、提高強(qiáng)度尤其是后期強(qiáng)度的作用，同時(shí)其較低的堿含量避免了堿骨料反應(yīng)對(duì)結(jié)構(gòu)的破壞。 在上述研究基礎(chǔ)上分析得出了滿足標(biāo)準(zhǔn)要求的膨脹劑配方在煅燒氧化鈣-固硫灰-石膏三組分相圖中圍成的范圍，其限制膨脹率可在0.029%-0.129%范圍變化。其中30%f-CaO、40%CFB固硫灰、30%CaSO4配制的膨脹劑能達(dá)到最大的膨脹率，適宜配制對(duì)膨脹性能要求較高的Ⅰ型混凝土膨脹劑，且可在較低的膨脹劑摻量下（6%-8%）達(dá)到滿足標(biāo)準(zhǔn)要求的膨脹率。 論文建立了可用于指導(dǎo)復(fù)合膨脹劑組成設(shè)計(jì)的CFB固硫灰組成、膨脹劑組成與膨脹性能之間的關(guān)系模型：理想狀態(tài)下，7d齡期標(biāo)準(zhǔn)試樣中每1mol鈣礬石約產(chǎn)生9.06%的限制膨脹率、1mol氫氧化鈣約產(chǎn)生1.52%的限制膨脹率。對(duì)于組分波動(dòng)較大的CFB固硫灰可以利用其組成計(jì)算膨脹源的生成量進(jìn)而計(jì)算出膨脹率值，同時(shí)還可以設(shè)計(jì)具有特定膨脹率的膨脹劑配方。對(duì)于組成一定的膨脹劑，其摻量、抗壓強(qiáng)度與膨脹率三者之間的關(guān)系可以用方程量化表征，用于指導(dǎo)膨脹劑摻量的設(shè)計(jì)。 論文采用XRD對(duì)膨脹產(chǎn)物進(jìn)行定量分析并結(jié)合SEM分析，探討了復(fù)合膨脹劑的作用機(jī)理，分析認(rèn)為鈣礬石和氫氧化鈣均存在溶解沉淀反應(yīng)和局部化學(xué)反應(yīng)兩種形成途徑，膨脹劑中的煅燒氧化鈣溶出Ca2+、OH-，CFB固硫灰和石膏溶出SO42-和AlO2-，在孔洞處沉淀析出結(jié)晶良好的長(zhǎng)桿狀鈣礬石及結(jié)晶完整的氫氧化鈣。氫氧化鈣邊緣及表面析出的針狀鈣礬石，是溶液中SO42-和AlO2-直接在氫氧化鈣晶體表面生成的，，符合局部化學(xué)反應(yīng)機(jī)理，而這部分氫氧化鈣晶體也應(yīng)是通過(guò)局部化學(xué)反應(yīng)生成的。兩種形貌的鈣礬石共同作用產(chǎn)生較高的膨脹。膨脹劑中氧化鈣含量為20%-30%時(shí)，鈣礬石仍然是復(fù)合膨脹劑的主要膨脹源。 論文的研究結(jié)果既實(shí)現(xiàn)了固硫灰高附加值的資源化利用，又為開(kāi)發(fā)一種高性能的混凝土膨脹劑奠定了相應(yīng)的理論基礎(chǔ)。
[Abstract]:Circulating fluidized bed (CFB) boiler combustion has become clean coal-fired power generation technology vigorously developing in our country, the sulfur ash desulfurization of circulating fluidized bed boiler (hereinafter referred to as CFB fbcf) emissions than ordinary coal high, and its composition and structure are different from fly ash by using fly ash, may have a greater harm therefore, sulfur ash CFB as one of the largest industrial solid wastes new, is an urgent problem to use its resources. According to the sulfur ash CFB containing f-CaO, CaSO4 and Al2O3 activity in preparation of calcium oxide - calcium sulphoaluminate composite expansive agent component, this paper used the preparation of concrete expansive agent system for the utilization of sulfur dust CFB, reduce environmental pollution, has important significance.
This paper studied the use of CFB sulfur ash and calcined calcium oxide, gypsum concrete composite expansive agent, explore the expansive agent content on properties of material and the influence of expansive agent performance. The results show that the calcium oxide calcined at different temperature, the expansive agent group in Chengdu will have a significant impact on the expansion properties of gypsum type little.1400 ~ C of calcium oxide calcined affect the expansion performance of the most suitable for the preparation of compound expansion agent, suitable content of 20%-30% composite expansion admixture performance to meet the standards; when the content of calcined calcium oxide, sulfur ash and gypsum content ratio changes will affect the formation of ettringite, when the expansion agent in nSO3/nAl2O3 about 3 can generate ettringite most, the largest expansion rate. Sulfur ash in composite expansion to provide expansion source of reactants and partial expansion agent to increase the strength of the source, especially the late strength, at the same time The lower alkali content avoids the destruction of the structure by the alkali aggregate reaction.
Based on the research on the analysis of the composition in meet the expanding range of sulfur ash calcined calcium oxide - gypsum three component phase diagram formed by the requirements of the standard, the rate of expansion can be changed in the range of 0.029%-0.129%. The 30%f-CaO, 40%CFB fbcf, 30%CaSO4 compound expansion agent can achieve the largest expansion rate the type, suitable for the preparation of high performance concrete expansive expansive agent, and can be expansionagentmixing lower (6%-8%) to meet the expansion rate of the standard.
Established in this paper can be used to guide the design of the CFB composite expansive agent composed of sulfur ash, expansive agent and expansion of the relationship between the performance model: ideally, 7d age standard samples per 1mol of ettringite produces about 9.06% limited expansion ratio, 1mol calcium hydroxide produces about 1.52% limited expansion ratio. For the component the fluctuation of CFB fbcf can use its composition and then calculate the expansion rate of value generation expansion sources, also can be designed with specific expansion rate of expansion agent. For expansive agent content, the relationship between compressive strength and expansion rate of the three can be used to quantify the equation. Used to guide the design of expansive agent content.
This thesis adopts XRD to quantitatively analyze the expansion of products and combined with the SEM analysis, discusses the mechanism of compound expansion agent, analyzed that the dissolution precipitation reaction and local chemical reaction of two kinds of ways of forming are ettringite and calcium hydroxide, calcium oxide in the calcining expansion agent dissolved Ca2 +, OH-, SO42- and AlO2- CFB soluble solid sulfur ash and gypsum, calcium hydroxide precipitation crystallization good rod-shaped ettringite crystallization and complete in the hole. The needle shaped ettringite edge and surface precipitation of calcium hydroxide, in the solution of SO42- and AlO2- on the surface of calcium hydroxide crystals generated directly, in line with the local chemical reaction mechanism, which is generated by calcium hydroxide crystals should also be local chemical reaction. Common two kinds of morphology of ettringite expansion. The expansion of high content of calcium oxide agent 20%-30%, ettringite is still the main compound expansion agent Expansion source.
The research results not only achieve the resource utilization of sulfur fixing ash and high added value, but also lay a theoretical foundation for developing a high-performance expansive agent for concrete.

【學(xué)位授予單位】：華南理工大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2013
【分類(lèi)號(hào)】：TU528.042.4

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