【摘要】：我國是世界菱鎂礦資源最為豐富的國家之一,其中遼寧是我國菱鎂礦的主要產(chǎn)地。2011年,遼寧省菱鎂礦儲量有34億t,占我國總儲量的90%左右,約占世界總儲量的25%。菱鎂礦是碳酸鎂的礦物名稱。我國菱鎂礦的儲量、開采量及鎂質(zhì)耐火材料生產(chǎn)量以及耐火材料的出口量等均居世界首位。研究菱鎂礦的利用具有很大的價值。本論文通過用耐馳同步熱分析儀進(jìn)行菱鎂礦非等溫?zé)岱纸鈱嶒?通過TG和MS同時檢測樣品重量的變化和產(chǎn)生氣體的情況。用Coats-Redfern、FWO和KAS三種方法計算菱鎂礦熱分解的平均活化能是203KJ/mol,Coats-Redfern法得到其反應(yīng)機(jī)理是一級反應(yīng)。分析菱鎂礦熱重的結(jié)果,根據(jù)其開始分解和分解接近完全時,將實驗的溫度分別設(shè)定為400、650和700℃在氮氣和空氣氣氛下進(jìn)行等溫?zé)峤夂挽褵龑嶒?將分解產(chǎn)物進(jìn)行紅外、XRD和SEM分析。紅外結(jié)果分析可知菱鎂礦原礦的主要成分是碳酸根和有機(jī)物;隨著熱解的進(jìn)行,碳酸根和有機(jī)物含量逐漸減少。菱鎂礦原礦的XRD圖可知其主要成分為MgCO3。結(jié)合FTIR和XRD分析,400℃下菱鎂礦未分解;700℃菱鎂礦熱解完全,650℃菱鎂礦煅燒完全,生成氧化鎂。結(jié)合XRD和SEM分析,菱鎂礦原礦是六方晶體結(jié)構(gòu),其分解產(chǎn)物MgO是三方晶體結(jié)構(gòu)。用檸檬酸法和XRD法考察煅燒溫度和煅燒時間對菱鎂礦分解率和分解活性的影響。煅燒溫度過高,會浪費能源,也會降低菱鎂礦的分解活性;煅燒溫度過低,菱鎂礦分解不完全,其活性也會下降。用檸檬酸法和XRD法分析氧化鎂的活性,得到氧化鎂活性與煅燒溫度和煅燒時間的關(guān)系。結(jié)果發(fā)現(xiàn)當(dāng)煅燒溫度是650℃煅燒45min時氧化鎂的活性最好。用活性較好的三種氧化鎂研究其濕法煙氣脫硫反應(yīng)特性,再選擇活性好的一種氧化鎂分別考察脫硫溫度、氧化鎂濃度、煙氣中不同SO2和O2濃度對氧化鎂濕法脫硫效率的影響。結(jié)果表明:不同實驗條件下,脫硫漿液pH值在脫硫反應(yīng)初期出現(xiàn)快速下降,隨后下降較緩慢;脫硫漿液pH值大于6時,脫硫效率均達(dá)到100%;pH值小于6時,脫硫效率迅速下降。在40℃時其脫硫效果最佳;MgO的濃度越高,脫硫效果越好;煙氣中SO2濃度越高,有效脫硫時間越短;煙氣中含有O2時使脫硫效果下降。對脫硫產(chǎn)物進(jìn)行XRD和TG-MS分析,結(jié)果表明通入煙氣中不含氧氣時脫硫產(chǎn)物主要是MgSO3和MgSO4,通入氧氣后脫硫產(chǎn)物主要是MgSO4。
[Abstract]:China is one of the countries with the most abundant magnesite resources in the world, among which Liaoning is the main producer of magnesite in our country. In 2011, the reserves of magnesite in Liaoning Province were 3.4 billion tons, accounting for about 90% of the total reserves in China, and about 25% of the total reserves in the world. Magnesite is the mineral name of magnesium carbonate. China's magnesite reserves, mining capacity, magnesia refractory production and exports of refractories are ranked first in the world. It is of great value to study the utilization of magnesite. In this paper, the non-isothermal thermal decomposition experiment of magnesite was carried out by using a car-resistant synchronous thermal analyzer, and the variation of sample weight and the gas production were detected by TG and MS at the same time. The average activation energy of magnesite thermal decomposition calculated by Coats-Redfern,FWO and KAS is 203KJ / mol Coats-Redfern method. The reaction mechanism is first-order reaction. The results of thermogravimetric analysis of magnesite are analyzed. When the decomposition and decomposition of magnesite begin to be nearly complete, the experimental temperatures are set at 400650 鈩，

本文編號：2429433