JPH0112804B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for reusing a reducing agent in a reduction iron manufacturing process using a carbonaceous solid reducing agent.

In this type of reduction ironmaking process, coke powder is charged into a reduction furnace as a carbonaceous solid reducing agent, but in order to prevent dust generation, coke powder with a particle size of less than 1 mm is removed before being charged. In this case 1mm
Smaller particle size coke powder is used as sintering coke in sintering machines. Therefore, there is a problem in that such a method cannot be applied to a general plant construction site that does not have blast furnace peripheral equipment such as a sintering machine.

This invention has been proposed to solve the above-mentioned problems, and its purpose is to provide a method for reusing reducing agent in which all of the nu-fied reducing agent can be used.

The reducing agent reuse method according to the present invention classifies the carbonaceous reducing agent before inputting it into the reduction furnace, directly inputs the carbonaceous reducing agent with a predetermined particle size or more into the reduction furnace, and granulates the carbonaceous reducing agent with a particle size smaller than the above-mentioned particle size and then reduces it. Put it into the furnace,
Classifying the mixture of unconsumed carbonaceous reducing agent and desulfurizing agent discharged from the reduction furnace and from which metallized iron has been separated;
The mixture having a predetermined particle size or more is recycled to the reduction furnace, and the mixture having a particle size smaller than the above-mentioned size is granulated and then recycled to the reduction furnace.

The present invention will be described below based on an illustrated embodiment. The reduction iron manufacturing process according to the present invention includes a crusher 1, a classifier 2, an underwater granulator 3, a reduction furnace 4, a separator 5, a classifier 6, an underwater granulator 7, a dehydrator 8, a dryer 9, and a roaster. It consists of 10.

In such a process, the carbonaceous solid reducing agent C is first pulverized to a predetermined particle size by a pulverizer 1, and then classified by a classifier 2.
It is directly put into the reduction furnace 4 as a reducing agent. 1
Those smaller than mm are granulated in an underwater granulator 3 to a size of 1 mm or more using asphalt A as a binder, and then fed into a reduction furnace 4 as a reducing agent.

Iron ore pellets IO and desulfurization agent Fl of 3 mm or less are charged into the reduction furnace 4. What is discharged from the reduction furnace 4 is metallized iron Fe, unconsumed reducing agent C, and desulfurizing agent Fl, which are separated by a separator 5 into a mixture of metallized iron Fe, unconsumed reducing agent C, and desulfurizing agent Fl. Ru.

A mixture of these unconsumed reducing agent C and desulfurizing agent Fl is sent to a classifier 6, and those with a diameter of 3 mm or more are recycled to the reduction furnace 4 as a reducing agent, and those smaller than 3 mm are sent to an underwater granulator using asphalt A as a binder. It is granulated by 7. Here, the unconsumed reducing agent C is separated from the desulfurizing agent Fl and granulated, and recycled to the reduction furnace 4 as a reducing agent.

The separated desulfurizing agent Fl is dehydrated in a dehydrator 8, dried in a drier 9, and sent to a roaster 10.

In addition, in the above-mentioned process, as shown by the dotted line in the figure, the carbonaceous reducing agent C with a particle size smaller than 1 mm classified by the classifier 2 is sent to the underwater granulator 7, and the carbonaceous reducing agent C is classified by the classifier 6. It is also possible to separate and granulate the mixture of the unconsumed reducing agent C and the desulfurizing agent Fl. Further, a part of the particles with a particle size smaller than 3 mm classified by the classifier 6 can be directly sent to the roaster 10 and used as a heat source.

As mentioned above, according to the present invention, it is possible to use all of the nu-fed reducing agent, and by making the reducing agent introduced into the reduction furnace have a particle size of 1 mm or more, dusting in the reduction furnace can be reduced. . In addition, by granulating New Feed with a particle size smaller than 1 mm underwater to eliminate fine powder, scattering loss in the kiln is reduced. Furthermore, underwater granulation increases the recovery rate of unconsumed reducing agent.

[Brief explanation of drawings]

The drawings are process diagrams showing manufacturing steps for carrying out the reducing agent reuse method according to the present invention. 1...Crusher, 2...Classifier, 3...Underwater granulator, 4
...Reduction furnace, 5...Separator, 6...Classifier, 7...Underwater granulator, 8...Dehydrator, 9...Dryer, 10...Roaster.

Claims (1)

[Claims] 1. When introducing iron ore pellets, desulfurization agent, and carbonaceous reducing agent into a reduction furnace, the carbonaceous reducing agent is classified, and those with a predetermined particle size or more are directly introduced into the reduction furnace, and those with a particle size smaller than the above are produced. After being granulated, it is put into a reduction furnace, the mixture of unconsumed carbonaceous reducing agent and desulfurization agent discharged from the reduction furnace and from which metallized iron has been separated is classified, and the mixture having a predetermined particle size or more is recycled to the reduction furnace. A method for reusing a reducing agent in a steel manufacturing process, characterized in that the particles having a particle size smaller than the above are recycled to a reduction furnace after being granulated.