發(fā)布時(shí)間：2018-05-01 18:45

  本文選題：褐鐵礦 + 磁化焙燒��； 參考：《內(nèi)蒙古科技大學(xué)》2015年碩士論文

【摘要】：鋼鐵材料是目前及將來(lái)長(zhǎng)時(shí)間內(nèi)國(guó)家經(jīng)濟(jì)發(fā)展的重要基礎(chǔ)之一。然而，，目前我國(guó)高品位鐵礦資源已日漸匱乏。以褐鐵礦為代表的低品位難選鐵礦的高效檢選已經(jīng)成為實(shí)現(xiàn)我國(guó)經(jīng)濟(jì)、社會(huì)可持續(xù)發(fā)展過(guò)程中必須解決的問(wèn)題。 傳統(tǒng)的褐鐵礦焙燒還原主要是在豎爐、沸騰爐和回轉(zhuǎn)窯等中進(jìn)行，但是這些設(shè)備存在能耗高、還原時(shí)間長(zhǎng)等缺點(diǎn)，造成設(shè)備整體結(jié)構(gòu)及相關(guān)技術(shù)不過(guò)關(guān)，不僅還原焙燒質(zhì)量較差，而且操作管理難度大，結(jié)構(gòu)復(fù)雜，投資高，收塵系統(tǒng)復(fù)雜�；�于內(nèi)蒙古固陽(yáng)褐鐵礦循環(huán)流化床磁化焙燒的開(kāi)發(fā)項(xiàng)目，為了深入了解微細(xì)褐鐵礦粉的還原機(jī)理及動(dòng)力學(xué)行為，本文針對(duì)褐鐵礦粉在中、低溫下氣體還原的過(guò)程建立數(shù)學(xué)模型，對(duì)褐鐵礦磁化焙燒進(jìn)行數(shù)值模擬，為低品位褐鐵礦的應(yīng)用提供理論依據(jù)。 本文運(yùn)用同步熱分析儀研究CO還原褐鐵礦粉的動(dòng)力學(xué)過(guò)程。應(yīng)用掃描電鏡分析了脫水后褐鐵礦的結(jié)構(gòu)，利用比表面和孔隙度分析儀測(cè)定了比表面積和孔隙度的變化。結(jié)果表明，褐鐵礦的磁化焙燒是一個(gè)很容易進(jìn)行的反應(yīng)，在給定的條件范圍內(nèi)，同時(shí)受到環(huán)境溫度、反應(yīng)氣體濃度和顆粒自身大小的影響。由同步熱分析儀的結(jié)果可確定褐鐵礦的反應(yīng)活化能，細(xì)顆粒的礦粉具有較低的活化能。根據(jù)褐鐵礦脫水后的SEM圖和吸附等溫線BET分類分析得出脫水后的褐鐵礦具有高氣孔率，其曲線更符合第Ⅲ類吸附等溫線。 根據(jù)褐鐵礦粉磁化焙燒情況，建立的氣固還原反應(yīng)的動(dòng)力學(xué)模型包括顆粒內(nèi)非穩(wěn)態(tài)的傳熱方程、孔隙內(nèi)氣體傳輸方程和基于描述孔徑分布的改進(jìn)隨機(jī)孔模型的非均相化學(xué)反應(yīng)動(dòng)力學(xué)方程，采用全隱式有限體積法對(duì)控制方程進(jìn)行數(shù)值求解。利用MATLAB，模擬了在不同溫度、不同初始?xì)怏w濃度、不同礦粉粒徑及不同初始孔隙率的條件下反應(yīng)速率和磁化還原所需時(shí)間的關(guān)系，研究了一氧化碳濃度分布隨孔隙率的變化和不同粒徑、不同溫度下CO濃度沿褐鐵礦顆粒徑向方向分布的情況。結(jié)果表明，模型預(yù)測(cè)結(jié)果與實(shí)驗(yàn)結(jié)果吻合較好。提高反應(yīng)溫度可明顯縮短反應(yīng)完成的時(shí)間，褐鐵礦焙燒反應(yīng)速率與還原氣體CO濃度近似成正比，溫度升高時(shí)CO的有效滲入深度減小，當(dāng)顆粒的粒徑變大時(shí)，會(huì)影響反應(yīng)氣體向顆粒內(nèi)部的傳輸，具有大孔隙率的褐鐵礦將更有利于反應(yīng)的進(jìn)行。
[Abstract]:Iron and steel material is one of the important foundations of national economic development at present and in the future. However, high-grade iron ore resources in China are increasingly scarce. The efficient detection and separation of low grade refractory iron ore represented by limonite has become a problem that must be solved in the process of realizing the sustainable development of economy and society in our country. The traditional limonite roasting reduction is mainly carried out in shaft furnace, fluidized bed furnace and rotary kiln, but these equipments have the disadvantages of high energy consumption, long reduction time and so on, resulting in the whole structure of the equipment and related technology being not up to standard. Not only the quality of reduction roasting is poor, but also the operation management is difficult, the structure is complex, the investment is high, and the dust collecting system is complex. Based on the development project of magnetization roasting in circulating fluidized bed of Guyang limonite in Inner Mongolia, in order to deeply understand the reduction mechanism and kinetic behavior of limonite powder, a mathematical model for the reduction process of limonite powder at medium and low temperatures is established in this paper. Numerical simulation of magnetization roasting of limonite provides theoretical basis for the application of low grade limonite. The kinetic process of CO reduction of limonite powder was studied by means of synchronous thermal analyzer. The structure of limonite after dehydration was analyzed by SEM, and the changes of specific surface area and porosity were measured by using specific surface area and porosity analyzer. The results show that the magnetization roasting of limonite is a very easy reaction, which is affected by the ambient temperature, reaction gas concentration and particle size under given conditions. The reaction activation energy of limonite can be determined from the results of simultaneous thermal analyzer. According to the SEM diagram of limonite after dehydration and the BET classification analysis of adsorption isotherm, it is concluded that the dehydrated limonite has high porosity, and its curve is more in line with the third type adsorption isotherm. According to the magnetization roasting of limonite powder, the kinetic model of gas-solid reduction reaction is established, which includes the unsteady heat transfer equation in particles. The gas transfer equation in pores and the heterogeneous chemical reaction kinetics equation based on the improved stochastic pore model describing pore size distribution are numerically solved by the fully implicit finite volume method. The relationship between the reaction rate and the time required for magnetization reduction under different temperatures, different initial gas concentrations, different particle sizes and different initial porosity was simulated by MATLAB. The distribution of carbon monoxide concentration along the radial direction of limonite particles under different particle sizes and temperatures was studied. The results show that the predicted results are in good agreement with the experimental results. Increasing the reaction temperature can obviously shorten the reaction completion time. The roasting rate of limonite is approximately proportional to the CO concentration of the reductive gas, and the effective penetration depth of CO decreases when the temperature increases, and when the particle size becomes larger, the effective penetration depth of CO decreases with the increase of temperature. Limonite with large porosity will affect the transport of reaction gas to the particle, and limonite with large porosity will be more favorable to the reaction.
【學(xué)位授予單位】：內(nèi)蒙古科技大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2015
【分類號(hào)】：TD951

【參考文獻(xiàn)】

相關(guān)期刊論文 前10條

1 朱德慶;趙強(qiáng);邱冠周;潘建;王澤群;潘常甲;;安徽褐鐵礦的磁化焙燒-磁選工藝[J];北京科技大學(xué)學(xué)報(bào);2010年06期

2 陳金妹;張健;;ASAP2020比表面積及孔隙分析儀的應(yīng)用[J];分析儀器;2009年03期

3 張乃庚;閻慶鐸;王景寬;袁忠誠(chéng);;礦石粒度對(duì)磁化焙燒均勻性的影響[J];鋼鐵;1964年09期

4 張漢泉;余永富;彭澤友;陳雯;;黃梅褐鐵礦懸浮閃速磁化焙燒試驗(yàn)研究[J];鋼鐵;2009年07期

5 周建軍;朱慶山;王化軍;倪文;;某鮞狀赤褐鐵礦流化床磁化焙燒-磁選工藝[J];過(guò)程工程學(xué)報(bào);2009年02期

6 汪永斌;朱國(guó)才;池汝安;趙玉娜;程卓;;生物質(zhì)還原磁化褐鐵礦的實(shí)驗(yàn)研究[J];過(guò)程工程學(xué)報(bào);2009年03期

7 李秋菊;廖增麗;王秀;洪新;;中低溫氫還原鐵礦微粉過(guò)程的實(shí)驗(yàn)研究與數(shù)值模擬[J];過(guò)程工程學(xué)報(bào);2011年02期

8 李秋菊;洪新;王興慶;;低溫還原鐵礦微粉過(guò)程的數(shù)值模擬[J];材料與冶金學(xué)報(bào);2007年04期

9 郭明,商志才,俞慶森,劉文杰,胡桂香;化合物分子體積計(jì)算方法的研究[J];浙江大學(xué)學(xué)報(bào)(理學(xué)版);2003年05期

10 陳甲斌;許敬華;;國(guó)內(nèi)外鐵礦石市場(chǎng)形勢(shì)分析[J];江蘇地質(zhì);2007年02期

相關(guān)博士學(xué)位論文 前1條

1 李秋菊;微/納米級(jí)鐵礦粉氣相還原動(dòng)力學(xué)研究[D];上海大學(xué);2008年

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