Reducing roasting method for powdered iron ores in tunnel kiln

Abstract

The invention discloses a reducing roasting method for powdered iron ores in a tunnel kiln, which is designed for solving the problems of low heat transfer efficiency, long reducing time, non-uniform material reduction quality, and the like when powdered iron ores are subjected to reducing roasting in a tunnel kiln. According to the invention, by reasonably selecting the particle size range and distribution of iron ores, iron ores with different particle sizes and reducing coal are mixed and distributed in layers, and then the obtained object is subjected to reducing roasting, so that the iron ores with different particle sizes achieve a same roasting effect, thereby increasing the metal recovery rate of roasted iron ores, improving the quality of roasting, shortening the roasting time, reducing the roasting temperature, and lowering the production cost.

Description

Technical field [0001] The invention belongs to the technical field of metallurgy and relates to a tunnel kiln reduction roasting method of powdered iron ore. Background technique [0002] In the iron ore tunnel kiln direct reduction process, the reduction methods adopted for powdered iron ore include the reduction method of pulverized ore pelletizing, tunnel kiln canning method, pulverized ore and tunnel kiln powder tiling, and pelletizing tiling reduction. law. [0003] The reduction method of pulverized iron ore pelletizing is to mix the pulverized iron ore with reduced coal and mix it into a tunnel kiln for reduction. This method involves indirect contact between pellets and reduced coal and iron The problem of low ore reduction speed and uneven reduction quality. [0004] The tunnel kiln canning method is to put the concentrate powder, coal powder, and limestone powder into the reduction tank according to a certain proportion, and then push the kiln car equipped with the reduc...

AI Technical Summary

Problems solved by technology

Therefore, the heat transferred from the space in the kiln to the surface of the material is difficult to transfer to the material in the lower layer, making it difficult to increase the temperature of the material in the lower layer. , the temperature of the upper material can continue to rise, and the heat can be transferred to the lower material after the temperature of the upper material is increased, so that the temperature of the lower material rises, and the iron ore begins to reduce when the temperature of the lower material reaches above 600 °C; therefore, in iron ore In the stone reduction process, the temperature of the lower material is lower than that of the upper material, and the reduction of the lower material takes a long time; generally, in order to fully restore the lower material, the method of increasing the reduction temperature and reduction time of the tunnel kiln is adopted, but increasing the reduction temperature is restricted by the tunnel kiln. Fuel, kiln equipment constraints, increasing the reduction time is restricted by production energy consumption and product cost