Process for producing direct reduced iron with coal as reducer

Abstract

The invention provides a process for production of direct reduced ferrum with coal as a reducer: covering the surface of pellet with a protective layer made up of inorganic inert substance with disk cuber or cylinder cuber after the iron material is made into pellet basing on the present technology, then covered pellets being produced, sending the covered pellets into the kiln to run reduction reaction, after reduction sending the covered pellets into cooling barrel and cooling them rapidly, then disintegrating or grinding and letting the inorganic inert substance release the pellets, the direct reduced ferrum pellets being obtained after sifting. Producing direct reduced ferrum with the method, pellets don't bind with each other, or with retort, and the temperature of the inside of kiln can be raising to 1100 to 1250 deg, as a result, the reduction reaction rate and metallising ratio are highly increased, and the productive efficiency and productive cost improved.

Description

technical field [0001] The invention relates to an iron metallurgical method, in particular to a method for producing direct reduced iron using coal as a reducing agent. Background technique [0002] There are many specific implementation methods for the production method of producing direct reduced iron with coal as a reducing agent, such as cooling pellets-one-step method of rotary kiln, preheating and roasting of ordinary pellet chain grate machine-one-step method of rotary kiln, etc. The basic process route is to first make iron-containing raw materials into pellets. When preparing pellets, thermal adhesives or adhesives and reducing agents can be added in a certain proportion to form pellets, and at the same time provide the reducing agent required by the process. , and then send the pellets into the kiln for high-temperature reduction reaction. According to the process requirements, a certain proportion of reducing agent and desulfurizer can be sent into the heating ki...

AI Technical Summary

Problems solved by technology

The equipment capacity of this production method is greatly affected by the temperature in the kiln. When the temperature is low, the carbon monoxide content is small, the time required for reduction is long, the metallization rate is low, and the production efficiency is low. Therefore, a higher kiln should generally be used. However, under the existing technology, when the temperature in the kiln is high, the pellets will stick to each other and form large pieces of material, which will seriously affect the smooth discharge of materials, and even completely block the kiln, and the kiln has to be shut down for treatment. , the fallen fine-grained mineral powder, etc. will also form low copolymers, stick to the refractory bricks inside the rotary kiln, form the ring, and also block the material passage in the kiln. For example, when the ball is put into the reaction tank, the ball The ball will stick to the inner wall of the tank, and it is difficult to take it out after the reaction