气相水化氧化镁制备氢氧化镁及其动力学研究

发布时间：2018-03-14 18:41

本文选题：氧化镁　切入点：氢氧化镁　出处：《大连理工大学》2015年硕士论文　论文类型：学位论文

【摘要】：菱镁矿轻烧镁水化法原料储量丰富,不消耗酸碱,因此被认为是最具优势制备氢氧化镁材料的方法。但直接液相水化法存在浆料过滤性差,形成膏状湿基物料,干燥能耗高等技术瓶颈。国家自然科学基金“气相水化轻烧镁制备氢氧化镁及其微结构转化和性能研究,No.21407032”提出利用气相水化法制备氢氧化镁,不需要过滤环节,直接解决了直接水化法的过滤性差、干燥能耗高、干燥后产品团聚结块等问题。本文在完成该项基金部分工作的前提下,开展了由菱镁矿轻烧镁制备氢氧化镁的工作,研究各种反应条件对水化率的影响,建立相关数学模型,并对其工业化的可行性进行经济核算。主要内容和结果如下：(1)反应条件对水化率的影响。考察了水化时间、水化温度、轻烧镁活性、轻烧镁物料高度和轻烧镁颗粒尺寸对水化率的影响,结果表明：氧化镁活性和水化温度的增加,较小的氧化镁物料颗粒及氧化镁物料高度都有利于水化反应的进行；水化率随着水化时间的增加而增加,直到趋于平稳。反应完全后,水化转化率可达到93%及以上。(2)轻烧镁气相水化过程的动力学。考虑到轻烧镁气相水化体系的复杂性,将轻烧镁物料看成一个多孔的片层状颗粒,对实验结果进行数据拟合和分析,结果表明：氧化镁水化过程符合内扩散控制的微粒模型,得到水化时间与氧化镁物料高度、水化转化率的经验公式为(3)经济核算。对菱镁矿轻烧镁气相水化制备阻燃级氢氧化镁工业化可行性进行了物料衡算、热量衡算及经济核算,计算得出气相水化法生产氢氧化镁的成本为1720元／吨,低于水镁石物理粉碎法。
[Abstract]:The magnesite light burning magnesium hydration method is rich in raw materials and does not consume acid and alkali, so it is considered to be the most advantageous method for the preparation of magnesium hydroxide materials, but the direct liquid phase hydration method has poor slurry filtration and forms paste wet base materials. The National Natural Science Foundation of China "preparation of magnesium hydroxide by gas phase hydration and light burning magnesium and its microstructure transformation and performance research no. 21407032" put forward the method of gas phase hydration to prepare magnesium hydroxide without the need of filtration. The problems such as poor filtration, high drying energy consumption and agglomeration of products after drying have been solved directly. In this paper, the preparation of magnesium hydroxide from magnesite by light burning magnesium has been carried out on the premise of completing the partial work of this fund. The effects of various reaction conditions on the hydration rate are studied, the relevant mathematical models are established, and the feasibility of industrialization is calculated. The main contents and results are as follows: 1) the effect of reaction conditions on the hydration rate. The hydration time and temperature are investigated. The effects of the activity of light calcined magnesium, the height of raw material and the particle size of light calcined magnesium on the hydration rate. The results show that the increase of MgO activity and hydration temperature, The smaller magnesium oxide particles and the height of magnesium oxide material are favorable to the hydration reaction, and the hydration rate increases with the increase of hydration time until it tends to be stable. The hydration conversion can reach 93% and above) the kinetics of the gas phase hydration process of light burned magnesium. Considering the complexity of the gas phase hydration system of light burned magnesium, the light burned magnesium material is regarded as a porous lamellar particle. The experimental results are fitted and analyzed. The results show that the hydration process of magnesium oxide accords with the particle model controlled by internal diffusion, and the hydration time and the height of magnesium oxide material are obtained. The empirical formula of hydration conversion is the economic calculation. The material balance, heat balance and economic calculation are carried out on the feasibility of preparing flame retardant magnesium hydroxide by vapor-phase hydration of magnesite. The cost of producing magnesium hydroxide by gas phase hydration is 1720 yuan / ton, which is lower than that of brucite physical comminution method.
【学位授予单位】：大连理工大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TQ132.2

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