Reduced iron powder production process

Abstract

The invention relates to a reduced iron powder production process which is characterized by including the steps: (1) distributing and weighing powdered iron, reduced pulverized coal and lime powder according to the weight ratio of 75-85:12-18:3-7, adding the powdered iron, the reduced pulverized coal and the lime powder into a damp mill for mixing and grinding after distribution to form wet materials by stirring; (2) conveying the wet materials to a ball press for pressing the wet materials into balls; (3) conveying finished balls into a grate for drying and transforming green balls into direct reduced iron-metalized pellets in a rotary hearth furnace; (4) enabling the pellets to directly enter a quenching tank or a quenching bath for rapid cooling after discharge, grinding the pellets into powder and then removing impurities in the powder to obtain primary iron powder; and (5) drying the primary iron powder in a dryer and then conveying the primary iron powder into a secondary reduction furnace for secondary fine reduction. In the novel process, direct reduced iron prepared by the rotary hearth furnace is used as the primary iron powder, primary iron powder produced by a tunnel kiln can be replaced, and accordingly, the problems in production of a current tunnel kiln are solved.

Description

technical field [0001] The invention relates to a production process of reduced iron powder. Background technique [0002] Reduced iron powder is the raw material for the powder metallurgy industry to manufacture iron-based metal parts. At present, the preparation process of reduced iron powder at home and abroad still uses the traditional tunnel kiln + fine reduction two-step process, that is, the first step is to reduce the iron concentrate powder into direct reduced iron in the tunnel kiln. The direct reduced iron becomes primary iron powder after crushing, grinding, screening and magnetic separation to remove the gangue and other impurities; the second step is to carry out fine reduction in the crawler-type reduction furnace with hydrogen as the reducing gas, and the unreduced The reduced residual iron concentrate powder is subjected to deep reduction, and a higher reduction temperature is used to remove the internal stress existing in the iron powder during the primary...

AI Technical Summary

Problems solved by technology

However, the production of reduced iron in tunnel kilns has serious problems of high production cost, high energy consumption, long time, heavy pollution and poor working conditions for workers.