形核剂在熔融态高炉渣中扩散过程的模拟研究

发布时间：2018-06-15 00:27

  本文选题：形核剂 + 颗粒密度　； 参考：《华北理工大学》2017年硕士论文

【摘要】：钢铁企业的生产过程中排出了大量高炉渣,其热值高,且多用来生产低附加值产品,造成了浪费资源、污染环境等严重问题,因此提高高炉渣的利用率是解决环保问题,促进钢铁企业发展循环经济的必要措施之一。由于高炉渣的主要成分与微晶玻璃成分相似,因此是制备微晶玻璃的理想废弃物。微晶玻璃是基础玻璃经过可控的晶化作用而形成的一种晶体相和玻璃相共存的多晶材料,玻璃的形核过程主要依靠非均匀形核,晶化过程需要一定的析晶活化能,形核剂的加入不但可以诱导非均匀形核,还能够降低所需析晶活化能,因此是熔融态高炉渣制备微晶玻璃的过程中必不可少的添加剂。形核剂在熔体中的扩散过程属于颗粒的自由扩散,为保证形核剂在不同粘度的熔体中分散均匀,有必要利用Fluent软件模拟不同密度、等效直径的形核剂颗粒在不同粘度熔体中的扩散过程,确定形核剂的混匀时间。通过数值模拟和物理模拟得出的结论如下:(1)颗粒的沉降时间与溶液的动力粘度成反比,颗粒的等效直径成正比。溶液的动力粘度越小,颗粒的等效直径越大时,沉降所需的时间越短,最终悬浮于溶液中的颗粒浓度越低。(2)形核剂的混匀时间与形核剂的密度、等效直径成正比,与熔体的粘度成反比。对于等效直径为100μm的Ti O2、Ca F2和P2O5颗粒在熔体温度为1385℃时的混匀时间分别为818s、1187s和1518s。
[Abstract]:In the production process of iron and steel enterprises, a large amount of blast furnace slag is discharged, and its calorific value is high, and it is mostly used to produce low value-added products, which results in serious problems such as wasting resources and polluting the environment. Therefore, to improve the utilization ratio of blast furnace slag is to solve the problem of environmental protection. One of the necessary measures to promote the development of circular economy in iron and steel enterprises. Because the main composition of blast furnace slag is similar to that of glass-ceramics, it is an ideal waste for preparing glass-ceramics. Glass-ceramics is a kind of polycrystalline material formed by the controllable crystallization of the basic glass. The nucleation process of the glass mainly depends on the heterogeneous nucleation, and the crystallization process requires a certain crystallization activation energy. The addition of nucleating agent can not only induce heterogeneous nucleation, but also reduce the required crystallization activation energy, so it is an essential additive in the preparation of glass-ceramics from molten blast furnace slag. The diffusion process of nucleating agent in melt belongs to the free diffusion of particles. In order to ensure the uniformity of nucleating agent in melt with different viscosity, it is necessary to simulate different density by fluent software. The diffusion process of nucleating agent particles with equivalent diameter in different viscosity melts and the homogenization time of nucleating agents were determined. The results obtained by numerical and physical simulation are as follows: (1) the settling time of the particles is inversely proportional to the dynamic viscosity of the solution, and the equivalent diameter of the particles is in direct proportion. The smaller the dynamic viscosity of the solution is, the larger the equivalent diameter of the particles is, the shorter the settling time is, and the lower the particle concentration in the solution is, the lower the mixing time of the nucleating agent is, and the equivalent diameter is proportional to the density of the nucleating agent. It is inversely proportional to the viscosity of the melt. When the melt temperature is 1385 鈩，

本文编号：2019686