JP2005240087A - Briquette for raw material for steelmaking and method for manufacturing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for manufacturing briquettes for a raw material for steelmaking in which shot residue can be effectively recycled, and to provide a method for manufacturing the same. <P>SOLUTION: Grinding sludge B which contains grinding-wheel swarf of ferrous metal and grinding fluid containing oil and water is mixed with shot residue S to obtain a flocculent agglomerate M. The flocculent agglomerate M is compacted to prepare a brittle compact C where the grinding-wheel swarf in a fibrous state is roughly sheared and excess water and oil are removed. The brittle compact B is impregnated with an auxiliary agent D for solidification to undergo solidification, followed by drying. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a briquette for a steelmaking raw material and a method for producing the same, and more particularly to a technique for effectively using shot soot generated when shot blasting is performed on an iron-based metal.

Chips generated when grinding ferrous metals such as bearing steel and carburized steel (hereinafter used as a concept that includes polishing, superfinishing polishing, lapping, etc.) are used for grinding fluids and abrasives containing moisture and oil. It is recovered as a cotton-like (fibrous) grinding sludge. Since this grinding sludge contains a large amount of pure iron, it has been attempted to reuse it as a raw material for steelmaking. For example, Patent Document 1 discloses a technique in which the grinding sludge is compression-molded and then impregnated with a solidification auxiliary and reused as a briquette for a steelmaking raw material.
On the other hand, since the shot soot produced when shot brass is applied to an iron-based metal generally contains iron powder and used shot balls (steel balls), it can be an effective resource as a steelmaking raw material. However, since this shot soot is easy to ignite or scatter, handling such as transportation and storage is difficult, and it is disadvantageous in terms of technology and cost to reuse. For this reason, the actual situation is that the shot culvert is disposed of as industrial waste.
JP 2002-129248 A (FIG. 1)

However, such landfill disposal of shot dredging is not preferable from the viewpoint of effective use of resources. There are also problems of causing environmental degradation and high disposal costs.
The present invention has been made in view of the above problems, and an object of the present invention is to provide a briquette for a steelmaking raw material and a method for producing the same, which can effectively reuse shot straw.

The briquette for steelmaking raw material of the present invention for achieving the above object is a dried briquette containing iron and oil, and a solid agglomerate containing iron metal grinding chips and shot soot is solidified. It is characterized by being solidified using a solubilizing aid.
Since the briquette for steelmaking raw material constituted in this way is a dry solid substance, handling such as transportation and storage is easy. Moreover, since oil is contained, it is prevented that the pure iron in a briquette oxidizes. Therefore, the grinding chips and shot iron can be reused as high-quality steelmaking raw materials.

  It is preferable that the briquette for steel making contains 5 to 25% by weight of shot wrinkles, thereby ensuring appropriate bulk density and mechanical strength. That is, if the shot soot is less than 5% by weight, the bulk density becomes small, and depending on the type of the blast furnace, there is a possibility that the briquette does not fall smoothly when it is put into the blast furnace. If the shot wrinkle exceeds 25% by weight, when the shot wrinkles are unevenly distributed, the briquettes easily break from the unevenly distributed shot wrinkles.

  The shot trough is preferably a steel shot ball. In this case, since the iron oxide content is low, it is more suitable as a raw material for steelmaking. That is, the shot basket generally contains steel shot balls and powder, the shot balls contain 90% by weight or more of pure iron, and the powder contains 60 to 65% by weight of oxidized iron powder. Therefore, the higher the content of the powder in the briquette, the higher the content of iron oxide. For this reason, it is necessary to increase the amount of reducing agent used during steelmaking, which is disadvantageous in terms of cost, but if shot balls from which the powder is removed are used as shot troughs, the content of iron oxide in briquettes Therefore, the amount of reducing agent used can be reduced accordingly.

  In addition, the method for producing briquettes for steelmaking raw materials of the present invention obtains a flocculent aggregate by mixing shot sludge with grinding sludge containing ferrous metal grinding chips and a grinding fluid containing oil and moisture. A step of compression-molding the flocculent aggregate to obtain a brittle molded body having a predetermined shape in which fibrous grinding chips are sheared and excess water and oil are removed; and the brittle molded body is solidified. It comprises a step of impregnating the solubilizing aid and a step of drying the brittle shaped body impregnated with the solidifying aid in this order.

  According to the manufacturing method of briquettes for steelmaking raw materials having the above-described configuration, the fibrous grinding chips that have been difficult to shear conventionally are roughly sheared by compression molding of the flocculent aggregate, and can be easily performed together with shot iron. It can be solidified. Further, the solidification aid impregnated in the brittle shaped body can be solidified to a desired strength simply by compression molding the brittle shaped body. There is no need to grind finely.

  In the manufacturing method of the briquette, it is preferable to mix 10 to 30% by weight of the shot basket. If the shot wrinkle in the flocculent aggregate is less than 10% by weight, it is difficult to obtain briquettes having a large bulk density. Further, when the shot wrinkle in the cotton-like aggregate exceeds 30% by weight, it becomes difficult to solidify this, and when the shot wrinkles are unevenly distributed, the briquettes are easily broken from the unevenly distributed shot wrinkles.

  It is preferable to use steel shot balls as the shot trough. In this case, since the content of iron oxide is reduced, a briquette more suitable as a raw material for steelmaking can be obtained.

  As the solidification aid, it is preferable to use at least one selected from sodium silicate, colloidal silica, aluminum phosphate, and asphalt emulsion. Thereby, the brittle molded object containing an oil component can be solidified easily and firmly.

According to the briquette for steelmaking raw material of the present invention, it is possible to reuse the grinding chips and shot iron as a high-quality steelmaking raw material, which is useful for environmental conservation and reduces the disposal cost of these grinding chips and shot iron. can do.
In addition, according to the method for producing briquettes for steelmaking raw materials of the present invention, the brittle molded body can be simply compression molded without finely pulverizing the flocculent aggregate with the solidification aid impregnated in the brittle molded body. Since it can solidify to desired intensity | strength, the briquette for steelmaking raw materials can be manufactured easily and cheaply.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.
FIG. 1 is a process diagram showing a method for producing briquettes for steelmaking raw materials according to one embodiment of the present invention. In manufacturing the briquette A, first, grinding sludge B (see FIG. 1A) generated when iron-based metal is ground is shot on the grinding sludge B while being conveyed by the belt conveyor 1. The cocoon S is lowered to obtain a flocculent aggregate M (see FIG. 1 (b)). The grinding sludge B is a cotton-like one containing grinding chips and grinding fluid. Further, the shot cage S is generated when shot brass is applied to an iron-based metal, and includes a used shot ball thinned to a predetermined particle size or less by shot and 60 to 65% by weight of oxidized iron powder. It consists of powder. The mixing amount of the shot basket S is 10 to 30% by weight. When the shot wrinkle S in the cotton-like aggregate M is less than 10% by weight, it is difficult to obtain the briquette A having a large bulk density. Further, if the shot basket S in the cotton-like aggregate M exceeds 30% by weight, it becomes difficult to solidify in a subsequent process, and when the shot basket S is unevenly distributed, the briquette A is easily broken from the unevenly distributed shot S portion. Become.

  Next, the cotton-like aggregate M is pressurized and compressed to preliminarily adjust the contents of water and oil, which are components of the grinding fluid contained in the grinding sludge B. The pressure-compression of the cotton-like aggregate M is performed, for example, by being sandwiched between a pair of rolls 2 provided near the conveyance end of the belt conveyor 1 (see FIG. 1B). At this time, the flocculent aggregate M is preferably adjusted so that the water content does not exceed 50% by weight and the oil content does not exceed 10% by weight. Handling such as storage becomes easy.

Further, the flocculent aggregate M in which the moisture and oil contents are adjusted is compression-molded by a press using the mold 3 to obtain a brittle molded body C (see FIG. 1 (c)). By this compression molding, the spiral fibrous grinding chips contained in the grinding sludge B are roughly sheared. Further, excess water and oil are removed, and the moisture content of the brittle shaped body C is adjusted to 2 to 12% by weight and the oil content is adjusted to 1 to 5% by weight. Thereby, it is possible to effectively prevent the grinding chips from being oxidized by the minimum residual oil. In addition, since the water content of the grinding sludge B is adjusted in advance in a range not exceeding 50% by weight and the oil content not exceeding 10% by weight in the previous process, the moisture and oil content ratios of the brittle molded body C are compression molded. It can be adjusted easily and appropriately only by this.
The brittle molded body C is formed in a shape that is easy to handle, such as a cylindrical shape, a spherical shape, and a prismatic shape, and is hardened to such an extent that it does not collapse during transportation to the next process.

  Next, the brittle shaped body C is impregnated with a liquid solidification aid D. The impregnation of the solidification auxiliary D is performed, for example, by immersing the brittle molded body C in the solidification auxiliary D injected into the tank 8 while being conveyed by the belt conveyor 7 (see FIG. 1 (d)). . As the solidification aid D, it is preferable to use at least one selected from sodium silicate, colloidal silica, and aluminum phosphate. In this embodiment, sodium silicate is mainly used. This solidifying auxiliary D is preferably impregnated in an amount of 2 to 30% by weight. Thereby, the brittle molded object C can be solidified easily and firmly. In addition, as said solidification adjuvant D, organic binders, such as vinyl acetate, can also be used.

  Next, the brittle molded body C impregnated with the solidification aid D is cured (see FIG. 1 (e)) and dried to remove the contained water (see FIG. 1 (f)). Briquette A for raw material is obtained (see FIG. 1 (g)). This curing is preferably performed for about 2 days because the contained water can be removed reliably. In the curing, normal temperature or cooled air may be blown to rapidly cool the air. The briquette A thus obtained contains 5 to 25% by weight of the shot basket S.

  As the shape of the briquette A, in addition to the above-described columnar shape, etc., the peripheral portion has a round shape such as an oval shape, an almond shape, a rugby ball shape, and the thickness gradually increases from the peripheral portion toward the central portion. It may have a substantially pillow shape (see FIG. 2). By molding into such a shape, it is possible to obtain a briquette A that is not easily disintegrated strongly against a compressive load and that is difficult to cause partial breakage at corners or the like.

Since the briquette A obtained as described above is a porous material obtained by solidifying the brittle molded body C, the contained water can be easily and reliably removed by curing. For this reason, there is no possibility that bumping will occur or it will rise and be discharged even if it is put into the blast furnace as it is.
Moreover, since the content of the shot soot S in the briquette A is 5 to 25% by weight, it has an appropriate bulk density and mechanical strength. That is, the briquette A for the steelmaking raw material is required to drop smoothly without being raised at the time of charging into the blast furnace. For this reason, depending on the type of blast furnace, 0.2 or more may be required as a bulk density, but if the shot soot in Briquette A is less than 5% by weight, this requirement may not be satisfied. Further, when the shot wrinkle in the briquette A exceeds 25% by weight, when the shot wrinkle is unevenly distributed in the briquette A, the briquette A is easily broken from the shot wrinkle portion.

Furthermore, in the manufacturing method of the briquette A, since processing is performed in a state in which a part of the oil of the grinding fluid is always held, oxidation of pure iron is effectively prevented. For example, it has been confirmed that briquette A manufactured using grinding sludge B containing grinding chips of bearing steel (SUJ-2) contains 60 to 90% by weight of pure iron. Therefore, the melting yield is as high as 80% or more, and can be provided to steel makers as a high-quality steelmaking raw material for a fee. In addition, it is easy to transport and handle in solid form.
And since the said manufacturing method can solidify the said cotton-like aggregate M, without requiring the process which grind | pulverizes and refines | miniaturizes the cotton-like aggregate M, the briquette A can be manufactured efficiently.

  The above-described method for producing briquette A is particularly suitably applied to reuse grinding chips containing 0.2 wt% or more of carbon. Such grinding chips have a large spring back and are difficult to solidify. By applying the manufacturing method of the present invention, the briquette A solidified by eliminating the influence of the spring back can be obtained. Can be easily obtained. In addition, as a representative example of the grinding chips containing 0.2 wt% or more of carbon, there can be mentioned grinding chips of bearing steel.

  In the above-described embodiment, the shot basket S having a used shot ball and a powder containing oxidized iron powder is used, but only the shot ball is obtained by selectively removing the powder. It may be used. In this case, since the content of iron oxide in the briquette A is reduced, it is possible to reduce the amount of reducing agent used during steel making. For this reason, it becomes a more suitable thing as a raw material for steelmaking raw materials.

It is process drawing which shows the manufacturing method of the briquette for the steelmaking raw materials which concerns on one Embodiment of this invention. It is a partial missing perspective view of a briquette.

Explanation of symbols

A Briquette B Grinding sludge C Brittle shaped body D Solidification aid M Cotton-like aggregate S Shot glaze

Claims (7)

  A dry briquette containing iron and oil, which is obtained by solidifying a flocculent agglomerate containing iron-based metal grinding chips and shot straw using a solidification aid. Briquette.   The briquette for steelmaking raw materials of Claim 1 containing 5-25 weight% of said shot straws.   The briquette for a steelmaking raw material according to claim 1, wherein the shot trough is a steel shot ball. A step of mixing a cotton cake with a grinding sludge containing a ferrous metal grinding chip and a grinding fluid containing oil and moisture to obtain a flocculent aggregate,
A step of compression-molding the cotton-like aggregate to obtain a brittle molded body having a predetermined shape in which fibrous grinding chips are sheared and excess water and oil are removed;
Impregnating the brittle shaped body with a solidification aid;
And a step of drying the brittle shaped body impregnated with the solidification aid in this order.   The manufacturing method of the briquette for the steelmaking raw materials of Claim 4 which mixes 10-30 weight% of said shot straws.   The method for producing briquettes for a steelmaking raw material according to claim 4, wherein the shot trough is a steel shot ball.   The method for producing briquettes for a steelmaking raw material according to claim 4, wherein the solidification aid is at least one selected from sodium silicate, colloidal silica, aluminum phosphate, and asphalt emulsion.

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