Enhanced reduction of multiple layers carbon containing pellets in rotary hearth furnace

Abstract

To enhance the reduction of multiple layers carbon containing pellets in rotary hearth furnace (RHF) process, a three-layer bed pellets were investigated using an electric furnace by simulating the RHF process. It was found that the metallization rate of the pellets on the upper layer was greatly higher than that on the middle and lower layers due to the low reduction efficiency and heat transfer efficiency. Various types and amount of reducing agent in carbon containing pellets showed different metallization rate and shrinkage rate, which affected the reduction efficiency and heat transfer efficiency of pellets. By optimization the type and amount of reducing agent, the metallization rates of reduced pellets for each layer of the bed all achieved more than 85% at 1300 °C and holding 20min, the metallization rates of reduced pellets for each layer of the bed reached over 90% at 1300 °C and holding 25 min.