JPS6315974B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for treating various types of furnace slag generated during iron and steel manufacturing processes, and more particularly, to a method for treating various types of furnace slag produced in iron and steel manufacturing processes. Regarding processing method.

Most of the blast furnace slag, converter slag, electric furnace slag, etc. generated in the iron and steel manufacturing processes were disposed of by dumping, but in recent years, from the perspective of reducing landfill sites and making effective use of resources, efforts have been made to recover iron in furnace slag and mine slag. is used as aggregate.

In the process of crushing furnace slag, the iron content is recovered as concentrate for iron and steel making using magnetism. Also, efforts have been made to grind the ore using an autogenous grinding mill. Examples of these prior art techniques include Japanese Patent Publication No. 51-33047, Japanese Patent Application Publication No. 147416/1972, Japanese Patent Application Publication No. 151615/1973,
Some are described in various publications such as No. 52-33163.

By the way, the contents of these prior art examples are summarized as follows: (1) The maximum dimension of the furnace slag to be treated is usually 300 mm, and even in special cases it is 500 mm or less.

(2) Furnace slag with a size of 300 mm or less and a high iron content of 50 to 60% is usually converted into concentrate as is, or polished with a rod mill or autogenous grinding mill to increase the iron content to 90% or more. It is made into concentrate.

(3) Furnace slag with dimensions of 300 mm or less and low iron content is
After crushing, magnetic sorting, and sieving, the ore is made into a concentrate as is, or it is ground in a rod mill or an autogenous grinding mill to increase the iron content to some extent and become a concentrate.

(4) Furnace slag with a size of 500 mm or more is sorted using a lifting magnet or visually, and only the furnace slag with a low iron content is crushed to a size of 300 mm or less, and various treatments are carried out.

(5) Furnace slag with a size of 300 mm or more and a high iron content is
There are many unprocessed items that have been piled up, and the processing is outsourced to specialized companies using the following method.

(b) Dropping a weight of about 2 to 5 tons.

(b) Gas cutting.

(c) Drill a hole and treat with dynamite.

(d) Drill a number of holes in a cross pattern and drive steel rods into them.

Therefore, the treatment of bulk furnace slag with a size of 300 mm or more and high iron content by a specialized contractor is an inefficient work that requires human labor, and is also a work with a high risk of scattering of furnace slag and iron pieces. It was hot.

For this reason, there has been a long-awaited development of a method for efficiently processing the above-mentioned lumpy slag and recovering it as concentrate for iron and steel manufacturing.

Therefore, in order to find a method for efficiently processing the above-mentioned lumpy slag, the present inventors conducted a test in which compressive force was applied to slag with a size of 500 mm or more and a high iron content, and the following results were obtained. I got it.

(1) When the iron content is pig iron, the iron content is roughly cleaved from the pig iron itself and the slag involved. At this time, the size of the slag attached to or entangled in the pig iron was distributed on the smaller side compared to the size of the coarsely chopped pig iron.

(2) When the iron content is steel, as the steel deforms,
The slag attached to or entangled in the steel was separated, and the steel itself was coarsely cracked from thin parts, surface irregularities, and defective parts such as internal cavities.

(3) The iron content of the furnace slag coarsely divided in items (1) and (2) above always increased, and in some cases exceeded 90%.

It is generally thought that it is impossible to roughly split the raw metal in furnace slag, but its properties are not homogeneous like that of steel plates, cast steel, and cast iron, and have many unevenness and sharp cracks on the surface. It contains many shrinkage cavities and blowholes, which are often referred to as casting defects. Therefore, if a compressive force is applied to the metal in the furnace slag as in the test described above, stress concentration will occur on the surface and internal defects of the metal, and the compressive strength will be several times higher than the compressive strength inherent to the iron content. Rough splitting is performed with one-fold compression force, and since slag is involved in the metal, the greater the ratio of slag to the rough cracked surface, the smaller the force required for rough splitting. It is recognized that

The present invention has been made with this point in mind.
It is an object of the present invention to provide a furnace slag treatment method that can efficiently recover concentrate for iron and steel manufacturing with a high iron content.

The furnace slag processing method of the present invention will be explained below based on the drawings. The figure shows the processing process for furnace slag. First, the bulk furnace slag with a size of 300 to 500 mm or more, such as blast furnace slag, converter slag, and electric furnace slag generated in the iron and steel manufacturing process, is used as a raw material. This is processed into a magnetic separator. Magnetic separation is performed to separate lumpy furnace slag with a high iron content of 50 to 60% or more and iron content of 50% or more.
Separate into low lumpy slag ~60% or less. Next, the lumpy furnace slag with a high iron content of 50 to 60% or more is put into a rough cracker, and compressive force is applied to it. If the iron content is pig, it will be coarsely cracked, and if the iron content is steel, it will be deformed. Alternatively, rough cracking is performed to reduce the size to 300 to 500 mm or less, and a part of the slag is exfoliated to increase the iron content. The aforementioned lumpy slag with a low iron content of 50 to 60% or less is finely processed using a compression crusher (oscillating crusher) similar to the conventional rock processing technology.

The furnace slag whose dimensions have been reduced and whose iron content has been increased by the above-mentioned rough splitting or deformation is then magnetically sorted by a magnetic separator to separate it into furnace slag with a high iron content and furnace slag with a low iron content. The furnace slag with a high iron content is recovered as a concentrate for iron and steel manufacturing, and the furnace slag with a low iron content is treated using conventional techniques as described above.

Thus, the iron content at dimensions of 300 to 500 mm or more
50~60% lump slag can be continuously and efficiently
The size is 500 mm or less, and the iron content is increased, and this is recovered as concentrate for iron and steel manufacturing.

In fact, 100 tons of block slag from a blast furnace with a size of 400 mm or more and an iron content of 50 to 60% was processed using the furnace slag processing method of the present invention, and iron was produced with a size of 250 mm or less and an iron content of 80 to 85%. - Concentrate for steelmaking could be efficiently recovered, and the time required for this was 3 hours, and the process was extremely efficient and workability was good.

However, with the conventional method of treating furnace slag by dropping a weight, iron content of 50 to
It took 40 hours to process 100 tons of lumpy slag from a 60% blast furnace, which was extremely inefficient and was highly dangerous due to the scattering of slag and iron pieces. It was hot.

As can be seen from the above explanation, according to the furnace slag treatment method of the present invention, the iron content is 50% when the size is 300 to 500 mm or more.
Concentrates for iron and steelmaking with an iron content of 80% or more can be continuously and efficiently recovered from ~60% lump slag.
Further, the processing of the furnace slag is carried out in a short time and extremely efficiently, and since the furnace slag and iron pieces are not scattered, the work is safer.

If the concentrate treated by the furnace slag treatment method of the present invention is further polished, it will be possible to obtain a concentrate with an iron content close to 100%, which will supply a wider range of raw materials for iron and steel manufacturing. be able to.

[Brief explanation of the drawing]

The figure is a flow sheet of the furnace slag treatment method of the present invention.

Claims (1)

[Claims] 1. In the treatment method for various types of furnace slag produced in the iron and steel manufacturing processes, bulk furnace slag with a size of 300 to 500 mm or more is magnetically sorted and separated into furnace slag with a high iron content and furnace slag with a low iron content. After that, compressive force is applied to the furnace slag with a high iron content, and those with iron content are coarsely cracked, and those with iron content are deformed or coarsely cracked, and the dimensions are reduced to 300 ~ 300. A method for treating furnace slag, which is characterized by reducing the size of slag to 500 mm or less and removing slag to increase the iron content.