Research On The Bed Temperature Distribution Of RHF Treatment On Zinc-bearing Wastes

It would produce approximately eighty millions of tons of dust in Chinese iron and steel industry. Dust contains harmful elements such as zinc, lead, arsenic, etc. Utilization rate of less than 20%. Heavy metal elements leached gradually with the rainwater that would pollute the environment if steel plant dust was dumped to the field or landfill. It has received a lot of practice and achieved success in disposing zinc dust by rotary hearth furnace. It would receive a metallization rate of iron pellets in separating zinc from steel plant. However, present rotary hearth furnace using thin layers in operation that resulted in low production efficiency and low capacity. Thus, thick layer operation became an important way to improve the rotary hearth furnace production capacity and efficiency.This paper focused on the steel plant metallurgical zinc-bearing dust and sludge, through the analysis of physical and chemical properties, proposed to use self contain carbon of metallurgical dust based on production of carbon-containing pellets, use rotary hearth furnace high temperature heating process to separate zinc of the metallurgical zinc-bearing dust, and in order to realize thick layer operation, promote carbon burning to enhancing heat transfer material layer by under the material layer ventilation. Haved a theoretical analysis on the rotary hearth furnace processing deal with zinc-bearing dust, and investigate the reduction characteristics, thermodynamic conditions, reduction carbon consumption and self-heating reduction characteristics of iron oxide and zinc oxide under the carbon-containing pellet conditions, to improving the theoretical basis of enhanced heat transfer experimental study. To build a simulation of the rotary hearth furnace heating process thick layer operation experimental platform on the basis of theoretical analysis.Rotary hearth furnace experimental used bag dust,explored thick layer operation of operation process experiment in the laboratorial RHF with a neutral atmosphere. Investigate Influence furnace temperature, ventilation quantity, carbon content on the bed temperature distribution.This paper gived a brief analysis of gas-solid heat transfer and physical and chemical change of roasting process. To regarded the roasting process heat condition as vertical One-dimen instability-heat-ransfer. On the basis of heat transfer theory in metallurgy, deduced the basic equation of the bed temperature distribution model, and introduced several sub models of this model, such as carbon combustion model、convective heat transfer coefficient、comprehensive heat transfer coefficient、the model of heat transfer in material layer. Correct the diameter of the pellet through the relationship between bed shrinkage with time, the computer programs were programmed by MATLAB, used implicit differential method to geted the bed temperature distribution.Through the established model, carried out orthogonal simulation experimental study of the five factors and four levels, through an intuitive method and variance method to research influence of Material thickness, the carbon content, furnace temperature, ventilation quantity, and hot-blast temperature on the bed temperature distribution. carried out influence of various factors on calcination time, bed temperature difference, proposed optimization of process parameters the RHF thick layer operation.