KR20020073804A - Recycling method of dust from steel refining furnace - Google Patents

Abstract

PURPOSE: A dust recycling method is provided which improves productivity, reduces treatment cost and prevents environmental pollution by recycling dust generated from electric arc furnace and refining furnace of steelmaking industry. CONSTITUTION: In a method for recycling dust by reinjecting dust generated from electric arc furnace and refining furnace of steelmaking industry into the refining furnace, the dust recycling method comprises the steps of collecting dust generated from the electric arc furnace and refining furnace of steelmaking industry; uniformly kneading the materials after adding cement and water to the collected dust; forming the kneaded dust mixture into a certain solid shape; drying the formed solid; and injecting the dried dust solid into the refining furnace, wherein an organic binder and a lubricating agent are further added in the kneading step in addition to the dust, cement and water, the kneaded dust mixture is continuously extrusion molded in a rod shape in the forming step, and the kneaded dust mixture is pressed using a press in the forming process.

Description

Steelmaking Furnace, Refining Furnace Dust Recycling Method {RECYCLING METHOD OF DUST FROM STEEL REFINING FURNACE}

The present invention relates to a method for recycling dust in a steelmaking furnace and a refining furnace, and more particularly, to collect dust generated in the steelmaking furnace and a refining furnace, and to form the collected dust into a solid having a predetermined shape and to re-refine it in a refining furnace. By input, it relates to a method for recycling the steel scrap and secondary raw materials contained in the dust.

In general, in order to make a variety of steel from iron ore, it is generally divided into four stages of steelmaking, steelmaking, casting and rolling process. Among these, the iron making process is a process in which iron ore is put in a blast furnace, and coke is burned to remove oxygen in iron ore and dissolve to make pig iron. Pig iron produced through such a steelmaking process has a high carbon content and contains a considerable amount of impurities such as phosphorus (P), sulfur (S), and silicon (Si), and thus has high hardness and brittleness. To make these pig irons stretch well and make them strong, the high-pressure and high-purity oxygen must be blown through the refining process to reduce the amount of carbon and remove harmful impurities.

Currently, in the smelting and steelmaking process, an electric furnace is mainly used as a refining furnace for steelmaking and refining. An electric furnace is a furnace for manufacturing steel by using heat transfer, and an electric conductor is used to supply current through an electrode. There are a variety of methods such as an arc furnace for melting scrap iron by arc heat generated between the scrap iron, an induction furnace for refining the resistance heat by induction current through electric heat to a coil wound around the crucible, and a reflection furnace.

1 is a schematic diagram showing the configuration of a general steelmaking furnace, in particular an arc furnace and a dust collecting device, with reference to this drawing will be described the dust collection process of the steelmaking furnace, refining furnace according to the prior art.

First, steelmaking scraps and subsidiary materials 10, such as pig iron, scrap metal, and limestone, are charged into the arc furnace 100 in which the refractory 110 is installed inside, and current flows through the electrode 120 to make steel scraps by arc heat. While the subsidiary material 10 is melted, refining is performed by introducing an inert gas such as high purity high pressure oxygen and argon gas through the gas injection port 130. Through this steelmaking process, and through the secondary refining furnace to obtain the steel (steel) by adjusting the amount of carbon contained in the steel scrap and secondary raw materials and other component changes.

In such a steelmaking process, intense melting occurs in the arc furnace 100 due to the arc heat, and the molten steel scrap and the subsidiary material 10 not only come out of the outside but also generate a large amount of dust. Since the dust contains toxic components harmful to the human body, a separate collecting device 200 is installed on the upper part of the arc furnace 100 to collect dust collected through the collecting device 200 in a separate container 300. do.

Conventionally, in order to process the dust generated in the above-mentioned steelmaking refining process, the dust collected by the dust collector is consigned to a specialized waste company, and the waste company transports the dust collected in the container to a landfill landfill. The dust treatment was performed.

However, for example, dust generated in the steel refining process contains about 60% of iron oxides and other components, which is very inefficient in terms of productivity and the cost of dust consignment. In addition to enormous consumption, there is a difficulty in landfilling due to the limited amount of landfill space for landfilling, and this landfill treatment has a fatal problem of causing environmental pollution.

On the other hand, if the dust generated in the refining process is re-introduced into the refining furnace, the dust may be utilized.However, as described above, the arc of the rough condition inside the steel refining furnace and the high pressure applied as necessary. Since dust is scattered to the outside of the refining furnace by gases such as oxygen, argon gas, etc., there is a limit that it cannot be added in the form of dust.

After all, an object of the present invention, by recycling the dust generated in the steelmaking furnace, refining furnace, to improve productivity, reduce consignment costs, dust recycling, which can actively contribute to the prevention of environmental pollution In providing a method.

In order to solve the above-mentioned problems of the prior art, the inventors of the present invention have been searching for a method for recycling dust in various angles, and when the collected dust is made into a solid body and re-introduced into the refining furnace, such as dust scattering. As a result of discovering that the object of the present invention can be achieved without causing problems, the present invention has been completed as a result of intensive studies.

1 is a schematic view showing the configuration of a general steelmaking furnace and a dust collecting device.

Explanation of symbols on the main parts of the drawings

10: scrap steel and auxiliary materials 20: slag

100: Acro 110: Refractory

120: electrode 130 gas inlet

200: collecting device 300: collecting container

In order to achieve the above object, the dust recycling method of the steelmaking furnace, refining furnace according to the present invention,

Collecting dust generated in the steelmaking furnace and refinery;

Adding cement and water to the collected dust and kneading uniformly,

Shaping the kneaded dust mixture into a predetermined solid shape,

Drying the molded solid body,

And injecting the dried dust solid into the refining furnace.

At this time, in the kneading step, in addition to dust, cement and water, by adding an organic binder (Binder) such as PVA and a lubricant, the molding process can be carried out more easily when the dust is formed into a solid body, It can extend the life.

At this time, instead of the above cement, limestone, steelmaking slag may be used as the inorganic binder.

As the molding process, known methods such as pressing and extrusion may be used, and in particular, the kneaded dust mixture may be continuously extruded in a rod form and cut into a predetermined size suitable for feeding into a refining furnace.

According to the present invention, when the dust is formed into a solid body and re-introduced into the refining furnace to carry out a refining process, the dust is maintained in a solid state until the melting point of the steelmaking scrap and the subsidiary raw material increases, so that the dust is a high pressure oxygen gas There is no fear of scattering due to the like, and the cement contained in the solid body can be easily absorbed into the slag again during the refining process and can be easily removed, and thus does not adversely affect the performance of the refining process and the quality of the final product.

Hereinafter, the present invention will be described in more detail with reference to a preferred embodiment of the method for recycling dust of a steelmaking furnace and a refining furnace according to the present invention. The following examples are merely to illustrate the present invention, and the present invention is not limited by these examples.

Example 1:

Scrap iron and secondary raw materials were charged inside the electric furnace, and high-purity oxygen was added to refine | purify, flowing an electric current through the electrode, melting the steelmaking iron and secondary raw materials. Dust was collected inside the container through a collecting device installed at the top of the furnace.

100 g of collected dust samples were analyzed using an atomic absorption spectrometer, and it was confirmed that the dust samples contained about 65% of iron oxide components.

700 kg of dust collected in the above process was put into a kneader, and 300 kg of cement and 300 kg of water were added to knead and mixed for 30 minutes uniformly. The kneaded dust mixture was introduced into an extruder manufactured by Hitachi, Inc. and extruded using a die having a circular outlet, whereby a rod-shaped solid body was obtained. The molded solid was cut to a size of about 100 cm, dried at room temperature, and then the dried dust solid was cut into a size of 10 cm and put into an electric furnace under refining to perform refining.

Example 2:

In addition to dust, cement and water, refining was carried out in the same manner as in Example 1 except that 10 kg of PVA and 1 kg of lubricant were further added.

Example 3:

300 kg of collected dust and 100 kg of water were added to uniformly kneaded and uniformly kneaded to prepare a mixture. The kneaded mixture was refined by the same procedure as in Example 1 except that the mixture was molded into a size of 10 × 10 × 5 cm using a press. Was performed.

As a result of the refining process as in Examples 1 to 3, the recovery rate of Fe was significantly improved in the main component of scrap metal as a raw material, and the waste generation amount was greatly reduced, thereby greatly reducing the waste disposal cost.

In the present invention described above, the steelmaking industry furnace and the refining furnace are mainly examples of the electric furnace, but the present invention is also applied to the dust treatment generated in the refining process using various decarburization furnaces such as induction furnaces, vacuum furnaces, and reflection furnaces in addition to the electric furnaces. This can be applied, but for convenience, the dust treatment during the refining of ordinary steel as an example, the present invention can also be applied to the refining process of alloy steel or scrap metal, such as special steel, such as low, medium and high carbon steel or stainless steel in addition to the ordinary steel. Moreover, it will be apparent to those skilled in the art that the present invention is applicable to a steelmaking process in addition to the steelmaking process.

In addition, in the present invention, the pressing process and the extrusion process were used as the molding process, but other well-known molding processes may be appropriately selected and used, and in the kneading step, other types of molding aids are added in addition to the binder and the lubricant such as PVA. May be

As described in detail above, according to the present invention, by recycling the dust generated in the steelmaking furnace, refining furnace in a simple process, the productivity is greatly improved by re-recovery of the raw materials, waste treatment by reducing the amount of waste generated Not only can they significantly reduce costs, they can also actively contribute to the prevention of environmental pollution.

Claims (4)

In the method of recycling dust by re-injecting the dust generated in the steelmaking furnace, refining furnace, Collecting dust generated in the steelmaking furnace and refinery; Adding cement and water to the collected dust and kneading uniformly, Shaping the kneaded dust mixture into a predetermined solid shape, Drying the molded solid body, And recycling the dried dust solids into the refining furnace. The method of claim 1, In the kneading step, in addition to dust, cement and water, dust recycling method, characterized in that further adding an organic binder and a lubricant. The method according to claim 1 or 2, In the molding process, a process of continuously extruding the kneaded dust mixture in the form of a rod is used. The method according to claim 1 or 2, The pressing process is used as said molding process, The dust recycling method characterized by the above-mentioned.