JP3711045B2 - Briquette for steelmaking raw materials - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a briquette for a steelmaking raw material, and more particularly to a technique for effectively using ferrous metal ground chips.
[0002]
[Prior art]
Chips generated when grinding ferrous metals such as bearing steel and carburized steel (hereinafter used as concepts including polishing, super-finish polishing, lapping, etc.) are grinding fluids and abrasives containing moisture and oil. It is recovered as a cotton-like (fibrous) agglomerate containing. Since this flocculent aggregate contains a large amount of pure iron, attempts have been made to reuse it as a raw material for steelmaking. However, since this flocculent agglomerate contains a large amount of moisture, if it is put into a blast furnace as it is, it causes a problem that bumping (steam explosion) occurs due to the moisture. Therefore, it is conceivable to remove the water in the flocculent aggregate by centrifugation or the like. In this case, the oil contained in the flocculent aggregate is also removed together with the water, and the flocculent aggregate spontaneously generates heat. Pure iron, which is a component of grinding chips, is transformed into iron oxide. For this reason, in order to reuse this as a steelmaking raw material, it is necessary to reduce it, and the use of a reducing agent increases the cost.
[0003]
Moreover, since the grinding chips to which the oil is attached are difficult to adhere to each other, it is difficult to solidify to a desired strength even if the cotton-like aggregate is compression-molded. Furthermore, for cotton-like aggregates containing a large amount of iron-based metal grinding chips having a carbon content of 0.2% by weight or more, the spring back during compression is large. It is difficult to solidify strongly. Therefore, even if the compression-molded cotton-like aggregate is put into the blast furnace, it flies up while being scattered and the problem is that the majority is collected by the dust collector.
Furthermore, since the fibrous grinding chips contained in the cotton-like aggregates are difficult to grind with a hammer mill or the like, the cotton-like aggregates cannot be finely sheared. For this reason, it is also difficult to process cotton-like aggregates into briquettes or the like.
Therefore, the actual condition is that the flocculent aggregates are disposed of in a landfill outsourced to a waste disposal company without being reused.
[0004]
[Problems to be solved by the invention]
However, landfill disposal of such flocculent aggregates is not preferable from the viewpoint of effective use of resources. There are also problems of causing environmental degradation and high disposal costs.
This invention is made | formed in view of the said problem, and it aims at providing the briquette for the steelmaking raw materials which can recycle | grind cutting chips effectively.
[0005]
[Means for Solving the Problems]
In order to achieve the above object, a briquette of the present invention is a dry briquette containing powdered pure iron and an oil component, and includes a ferrous metal grinding chip and a cotton containing a grinding fluid containing oil and moisture. The brittle molded body, which is obtained by removing excess water and oil content obtained by compression molding of the aggregates and retaining 1 to 5% by weight of pure iron oxidation-preventing oil, is impregnated with an inorganic solidification aid. (Claim 1).
Since the briquette for steelmaking raw material constituted in this way is a dry solid, there is no risk of bumping or rising even if it is put into the blast furnace as it is, and handling such as transportation and storage is easy. Become a thing. Moreover, since oil content is contained, it is prevented that powdery pure iron oxidizes.
[0008]
In the steelmaking raw material briquette (Claim 1 ), the inorganic solidification aid is preferably at least one selected from colloidal silica, sodium silicate, and aluminum phosphate (Claim 2 ). In spite of containing, it becomes solidified firmly.
[0009]
Briquettes for steelmaking raw material described above is preferably to include a solidification assistant 2-30 wt% (claim 3), which makes it more those more firmly solidified.
Wherein the blanking Ricketts is preferably those substantially pillow-shaped (claim 4), by which, it is possible to increase the compressive strength, partial damage is what hardly occurs.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.
FIG. 1 is a partially broken perspective view showing a briquette for a steelmaking raw material according to an embodiment of the present invention. This briquette A contains powdery pure iron and oil, and is obtained by finely shearing a cotton-like aggregate containing iron-based metal grinding chips and oil and water-containing grinding fluid. The powder is solidified by using a solidification auxiliary agent and dried to remove the moisture. The briquette A is formed in a substantially pillow shape.
[0011]
FIG. 2 is a process diagram showing a manufacturing method of the briquette A. In the production of this briquette A, first, the cotton-like aggregate B (see FIG. 2 (a)) of the grinding chips generated when grinding the ferrous metal is pressed and compressed, and the cotton-like aggregate B is then compressed. The contents of water and oil, which are the components of the grinding fluid contained in, are preliminarily adjusted. The pressure-compression of the cotton-like aggregate B is performed, for example, by being sandwiched between a pair of rolls 2 while being conveyed by the belt conveyor 1 (see FIG. 2B). At this time, the flocculent aggregate B is preferably adjusted so that the moisture content does not exceed 50 wt% and the oil content does not exceed 10 wt%. Handling such as storage becomes easy.
[0012]
Next, the flocculent aggregate B whose water and oil contents are adjusted is compression-molded by a press using the mold 3 to obtain a brittle molded body C (see FIG. 2 (c)). By this compression molding, the spiral fibrous grinding chips contained in the cotton-like aggregate 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 moisture content of the cotton-like aggregate B is adjusted in advance in a range that does not exceed 50% by weight and the oil content does not exceed 10% by weight, respectively, the moisture and oil content of the brittle molded body C is adjusted. It can be adjusted easily and appropriately only by compression molding.
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.
[0013]
Next, the brittle shaped body C is put into a mixer (or Henschel type mixer) 5 with a chopper mill equipped with a rotating blade 4 together with the solidification auxiliary D and pulverized (see FIG. 2 (d)). Thereby, the grinding chips of the brittle shaped body C can be further finely sheared (finished shear) to obtain a powder E containing pure iron powder and a solidification auxiliary D (see FIG. 2 (e)). . The major axis of the pure iron powder is about 3 to 1000 μm. When the brittle shaped body C is pulverized, the fibrous grinding chips in the brittle shaped body C are coarsely sheared in advance, and can be finished and sheared without any trouble. When the fibrous grinding chips in the brittle shaped body C are not coarsely sheared, it is very difficult to pulverize them with the mixer 5, and it is impossible to obtain a fine powder E. Is possible.
[0014]
Examples of the solidifying aid D include rice bran (rice bran spirit), molasses such as sugarcane, starches such as straw starch and corn starch, quicklime, colloidal silica, sodium silicate, aluminum phosphate, vinyl acetate sludge, asphalt emulsion, bentonite One or more selected from among these are preferably used. Such a solidification auxiliary D is preferably contained in an amount of 2 to 30% by weight. In particular, the rice bran and molasses can be effectively prevented from changing the quality of pure iron powder contained in a large amount in the powder E, and the price thereof is also low, which makes it extremely suitable as a solidification aid D. is there. Further, when the asphalt emulsion is kneaded and then separated into asphalt and water, caking occurs and strength is developed. As this asphalt emulsion, an anionic asphalt is preferably used.
[0015]
Next, a predetermined amount of the powder E is compression-molded by a press using the molding die 6 (see FIG. 2 (f)) to obtain a substantially pillow-shaped water-containing briquette F containing a large amount of pure iron. When the powder E is compression-molded, the solidification aid D and the moisture in the powder E can solidify the powder of pure iron to which oils and fats adhere to each other. In particular, when using powder E containing 5 to 6% by weight of water, 4% by weight of rice bran and 2% by weight of molasses, and 7 to 15% by weight of water and 2 to 10% by weight of vinyl acetate sludge, The water-containing briquette F solidified more firmly can be obtained.
The “substantially pillow shape” is a shape having a rounded periphery and gradually increasing in thickness from the periphery to the center, and includes an egg shape, an almond shape, a rugby ball shape, and the like. By forming into such a shape, it is possible to obtain briquette A that is not easily disintegrated strongly against a compressive load and that is difficult to cause partial breakage at corners and the like.
[0016]
Then, normal temperature or cooled air is blown onto the water-containing briquette F immediately after compression molding to rapidly cool it (see FIG. 2 (g)). Thereby, the said water-containing briquette F can be solidified easily and stably. Then, the briquette A for steelmaking raw materials can be obtained (refer FIG.2 (i)) by curing (drying) the water-containing briquette F and removing the water content (refer FIG.2 (h)). This curing is preferably performed for about 2 days because the contained water can be removed reliably.
[0017]
Since the briquette A obtained as described above is a porous material obtained by solidifying the powder E, the contained moisture 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. Further, since the processing is performed in a state where 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 cotton-like aggregate B containing grinding chips of bearing steel (SUJ-2) contains 84 to 95% by weight of pure iron. Therefore, the melting yield is very high at 90% 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.
[0018]
FIG. 3 is a process diagram showing another method for manufacturing the briquette A of the present invention. This manufacturing method is mainly different from the manufacturing method shown in FIG. 1 in that the pulverizing step of the brittle shaped body C is omitted. That is, in this manufacturing method, the brittle molded body C is obtained from the cotton-like aggregate B in exactly the same manner as the manufacturing method shown in FIG. 1 (see FIGS. 3A to 3C).
[0019]
And the brittle molded object C obtained through these processes is impregnated with the liquid solidification auxiliary 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. 3 (d)). . As the solidification aid D used in this production method, it is preferable to use at least one selected from colloidal silica, sodium silicate, and aluminum phosphate, whereby the brittle molded body C can be solidified easily and firmly. Can do.
[0020]
Next, the brittle molded body C impregnated with the solidification aid D is cured (see FIG. 3 (e)) and dried (see FIG. 3 (f)) to obtain a briquette A for a steelmaking raw material ( (See FIG. 3 (g)).
The briquette A obtained as described above can exhibit the same action as the briquette A obtained by the manufacturing method shown in FIG. Moreover, since the manufacturing method shown in FIG. 3 omits the step of pulverizing the brittle molded body C, the briquette A can be manufactured more efficiently.
[0021]
The manufacturing method of each briquette described above is particularly preferably applied to recycle 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.
[0022]
【The invention's effect】
As described above, briquette for steelmaking material according to claim 1 Symbol placement, since those solids which moisture has been removed, be charged directly to the blast furnace, with no risk of or flown up or cause bumping, The handling such as transportation and storage becomes easy. Moreover, since oil content is contained, it is prevented that powdery pure iron oxidizes. Therefore, it can be reused as a high-quality steelmaking raw material, which is useful for environmental conservation and can reduce the cutting waste disposal cost.
[0025]
According to the briquette for steelmaking raw material according to claim 2 , the inorganic solidification aid is at least one selected from colloidal silica, sodium silicate, and aluminum phosphate. It becomes solidified. For this reason, handling such as transportation and storage is further facilitated.
According to the briquette for a steelmaking raw material according to claim 3 , since the solidification aid is mixed in an amount of 2 to 30% by weight, the powder can be solidified more firmly. For this reason, handling such as transportation and storage is further facilitated.
According to the briquette for a steelmaking raw material described in claim 4 , since it is substantially in the shape of a pillow, the compressive strength can be increased and partial breakage hardly occurs. For this reason, handling such as transportation and storage is further facilitated.
[Brief description of the drawings]
FIG. 1 is a perspective view of a briquette partially cut away.
FIG. 2 is a process diagram showing a briquette manufacturing method according to the present invention.
FIG. 3 is a process diagram showing another method for manufacturing a briquette according to the present invention.
[Explanation of symbols]
A Briquette B Cotton-like aggregate C Brittle shaped body D Solidification aid E Powder

Claims (5)

Excess moisture obtained by compression molding a dry briquette containing powdered pure iron and oil, which contains iron-based metal grinding chips and a grinding fluid containing oil and moisture A briquette for steelmaking raw material, which is obtained by impregnating an inorganic solidification auxiliary agent into a brittle shaped body from which oil content is removed and retaining 1 to 5% by weight of oil for preventing oxidation of pure iron . Solidification assistant of the inorganic is colloidal silica, sodium silicate, briquette for steelmaking material according to claim 1, wherein at least one member selected from aluminum phosphate. Briquette for steelmaking material according to claim 1 comprising the solidification assistant 2-30 wt%.   The briquette for a steelmaking raw material according to claim 1, which has a substantially pillow shape. The briquette for a steelmaking raw material according to claim 1, wherein the flocculent aggregate includes grinding chips of bearing steel SUJ-2 and 84 to 95% by weight of pure iron.

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