Numerical Simulation Of Temperature Rising Characteristic During Coal-containing Chromite Fines Volume Reduction By Microwave Heating

Chrome is the main alloy element in special steel. But most of the chromite ore in China depends on import, input dependence degree being already up to over 95%, furthermore, fine ore increases year after year, causing the problem in agglomeration. The different way in utilizing chromite fines is analyzed in the paper and on base of that putting forward the new technology of utilizing chromite fines directly by microwave heating. It can take full advantage of the increasing raw materials of fine ore in volume reduction by microwave heating, which can simplify the process flow of ferrochromium smelting. It would be more significant in sustainable using chromite fines resource economically.The technology of microwave metallurgy develops along with the development of the technology of microwave heating. The numerical simulation of microwave heating process is the core of application of computer in microwave metallurgy research. Numerical simulation instead of part of the conventional experiments can increase research efficiency and decrease cost and energy sources, but also lessen environment pollution. The microwave distribution and heat transfer inside and outside affects both the quality of reduction and energy consumption. Hence the paper makes the material temperature field to be the center and performs the following research integrating the simulation and experiments.Temperature-rising properties of carbon-containing chromite fines during the process of reaction in microwave field are analyzed in the paper. Firstly, we predict the distribution of microwave by structure of resonance cavity, multi permatron coupling mode and the position of the material during heating process, which is validated by experiment. Dielectric property of material is changed with the temperature, which is reflected the ability of microwave absorption. Measuration of experiment and fitting subsection are adopted in the paper to deal with the problem of hard measurement of dielectric property. Combining with the variety of heat and physical properties, the equivalent dissipation can be calculated in different phase. The temperature inspired by dissipation power equation can be figured out by the equation of conversation of energy in simulation, finally the fitting curve of temperature-rising can be obtained. A way to analysis the material characteristic of temperature rising can be taken in different proportion. The way of microwave heating can satisfy the need of metallurgy from the result of the simulation result, which shows the high speed of temperature rising in microwave furnace.The modeling of microwave heating is expatiated according to the characteristic of microwave field and the material properties of temperature rising. The method confirms the boundary conditions, mesh of model and dependence of the physical properties on the temperature are given. Moreover, a method for coupling thermal field and magnetic field is putting forward and the basic process of numerical simulation of microwave heating is presented. The temperature fields in microwave heating process are simulation by finite element software, including the distribution of heat flow density and temperature field during the whole microwave heating process; the influence of material proportion and the prediction of temperature distribution in the crucible. The calculation results are validated by comparison with the experimental results. It is approved the validity and feasibility of the method which can provide reference to relevant study.