菱镁矿特性及其分解产物脱硫特性的研究
发布时间：2019-02-24 09:49
【摘要】：我国是世界菱镁矿资源最为丰富的国家之一,其中辽宁是我国菱镁矿的主要产地。2011年,辽宁省菱镁矿储量有34亿t,占我国总储量的90%左右,约占世界总储量的25%。菱镁矿是碳酸镁的矿物名称。我国菱镁矿的储量、开采量及镁质耐火材料生产量以及耐火材料的出口量等均居世界首位。研究菱镁矿的利用具有很大的价值。本论文通过用耐驰同步热分析仪进行菱镁矿非等温热分解实验,通过TG和MS同时检测样品重量的变化和产生气体的情况。用Coats-Redfern、FWO和KAS三种方法计算菱镁矿热分解的平均活化能是203KJ/mol,Coats-Redfern法得到其反应机理是一级反应。分析菱镁矿热重的结果,根据其开始分解和分解接近完全时,将实验的温度分别设定为400、650和700℃在氮气和空气气氛下进行等温热解和煅烧实验,将分解产物进行红外、XRD和SEM分析。红外结果分析可知菱镁矿原矿的主要成分是碳酸根和有机物;随着热解的进行,碳酸根和有机物含量逐渐减少。菱镁矿原矿的XRD图可知其主要成分为MgCO3。结合FTIR和XRD分析,400℃下菱镁矿未分解;700℃菱镁矿热解完全,650℃菱镁矿煅烧完全,生成氧化镁。结合XRD和SEM分析,菱镁矿原矿是六方晶体结构,其分解产物MgO是三方晶体结构。用柠檬酸法和XRD法考察煅烧温度和煅烧时间对菱镁矿分解率和分解活性的影响。煅烧温度过高,会浪费能源,也会降低菱镁矿的分解活性;煅烧温度过低,菱镁矿分解不完全,其活性也会下降。用柠檬酸法和XRD法分析氧化镁的活性,得到氧化镁活性与煅烧温度和煅烧时间的关系。结果发现当煅烧温度是650℃煅烧45min时氧化镁的活性最好。用活性较好的三种氧化镁研究其湿法烟气脱硫反应特性,再选择活性好的一种氧化镁分别考察脱硫温度、氧化镁浓度、烟气中不同SO2和O2浓度对氧化镁湿法脱硫效率的影响。结果表明:不同实验条件下,脱硫浆液pH值在脱硫反应初期出现快速下降,随后下降较缓慢;脱硫浆液pH值大于6时,脱硫效率均达到100%;pH值小于6时,脱硫效率迅速下降。在40℃时其脱硫效果最佳;MgO的浓度越高,脱硫效果越好;烟气中SO2浓度越高,有效脱硫时间越短;烟气中含有O2时使脱硫效果下降。对脱硫产物进行XRD和TG-MS分析,结果表明通入烟气中不含氧气时脱硫产物主要是MgSO3和MgSO4,通入氧气后脱硫产物主要是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，
本文编号：2429433
[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，
本文编号：2429433
本文链接：https://www.wllwen.com/kejilunwen/kuangye/2429433.html
