JPS6046301A - Method for molding minute metal - Google Patents

Abstract

PURPOSE:To obtain a steel manufacturing stock material generating no bumping in charging the same into a molten metal, by forming a mixture obtained by mixing a phenolic resin type binder and heavy oil with a pulverized minute metal into a lumpy form by compression molding. CONSTITUTION:0.5-1.0wt% of a phenolic resin type binder is added to a pulverized minute metal recovered from a metal trash or steel manufacturing slag. In this case, 0.2-0.5wt% of heavy oil or kerosene is further added. After these components are mixed under stirring, the resulting mixture is put in a mold frame and subjected to compression molding. By this method, the minute metal can be easily formed into a lumpy form. This lumpy substance has such a structure that the voids between metal minute particles are filled with the binder and the surface thereof is perfectly coated with said binder. Therefore, bumping is not generated even if said lumpy substance is charged into a molten metal. In addition, because of high burst strength and falling strength, said lumpy substance is sufficiently reacted with the molten metal in charging.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for molding fine metal particles.

Among the so-called metal scraps generated from various factories, fibrous or linear materials such as dry powder become lumps by simply compression molding them, so they can be used as they are or after heating and processing the lumps. Although it is easy to handle by pressure forming and using it as a raw material for steelmaking, it is not possible to form metal scraps in the form of smaller particles or minute metal objects recovered by magnetic separation from various types of slag in the ironmaking and steelmaking process even if they are simply compressed. First, it requires considerable temperature and pressure, even at high temperatures and pressures. Furthermore, such minute metals tend to retain a lot of moisture (in such cases, they must be dried, but they are easily oxidized during the drying process, so they must be dried in an atmosphere of 002 gas, N2 gas, or inert gas). With the above-mentioned difficulties, even when molding minute metals or molding those minute metals while being housed in a can, there are still many voids inside the molded body, and the voids and/or the can. There is air inside, which causes rust, and furthermore, when it is put into melting, the existing air or the gas generated from the rust expands rapidly, causing a bumping phenomenon.

Recently, methods have been developed to make these minute metals into lumps using a binder. ■
There are methods using polyvinyl alcohol (PVA) and carboxymethyl cellulose (CMC), but each method has advantages and disadvantages and still leaves room for improvement. That is, in the method (■), the amount of binder used is about 10%
This method involves kneading with water and molding under high pressure, but since a large amount of binder is used, the metal quality deteriorates and the processing time increases.Furthermore, these binders solidify due to hydration reaction. Because of this, when it is poured into molten metal, it instantly turns into powder and has little effect on clumping. In addition, the lumps produced by this method have low fall strength, and if dropped from a height of about 3 m, they will crack or turn into powder, making them inconvenient to handle. Next, in method (2), the raw materials are heated to 180-200°C, about 1-5% by weight of binder is added and mixed, and molded.

Although it is desirable that it contains almost no harmful components such as S and P, there are problems in actual operation, such as the fact that the binder is expensive and heating requires time and money. In addition, method (2) adds a small amount of binder (approximately 0.5% by weight), mixes it while sprinkling water, and molds it at room temperature and normal pressure, so that it can be made into a lump by a polymerization reaction, and the surface of the raw material is coated with this binder. Although subsequent oxidation can be prevented, there are still problems in that the binder is too expensive and the resulting lumps have low drop strength.

The present invention aims to provide a method for agglomerating fine metals that solves the above-mentioned problems, and the gist thereof is to add 0.5 to 1.0% by weight of a phenolic resin binder to small metals, and then mix them. A method for molding minute metals characterized by forming them into lumps, and adding 0.4 to 0.7% by weight of a phenolic resin binder to the minute metals and 0.2% of heavy oil or kerosene.
This is a method for molding minute metals, which is characterized by adding ~0.5% by weight and then mixing to form a lump.

The tests that led to the development of the present invention and their results are shown below.

Tests and results> Granular iron recovered from steelmaking slag (hereinafter referred to as granular iron),
Granular iron recovered from pig iron and desulfurization slag (hereinafter referred to as granular pig iron) is used as a raw material, and the binder is tephenol resin-based No.A.
P-P200 and AP-M750 (product name of two-component mixing resin) and Hp-300OA (product name) as well as heavy oil,
Mix kerosene in various proportions, pack it into a mold, and use a concrete pressure tester to change the compressive strength to form a cylinder (approximately 36+++
m f x approx. 30-m), and after curing in the air for 6 to 7 days, a drop test was conducted.For those that obtained good results, the binder amount and compressive strength were determined by large-scale compression* (press pressure 500 tons). cylindrical shape (130m+n f×100~2
In the case of granular iron and granular pig iron, 4 kg/piece and 8 kg/piece) were made and cured in the air for about 4 to 7 days.

After mixing in the same manner, the briquette (33X 33X 10~12m+n) was made by changing the briquetting pressure of the briquette machine, cured in the air for about 4~7 days, and hung up to a height of 5m with a riff mug. , and dropped it onto a steel plate to examine the state of destruction. The molded product was placed in a high-aluminum crucible, placed in a siliconite electric furnace, heated, and poked at intervals of about 100° C. with an iron rod to check the condition until it melted. The chemical analysis values of the raw materials used are shown in Table 1, and the particle size distribution is shown in Table 2.

Table 1 Chemical analysis values (wt%) Binder was blended with granulated pig iron and/or granulated iron in the proportions shown in Table 3, and the molding pressure was 3.5 tons as described above.
Table 4 shows the properties of the cylinders and aggregate minerals obtained in /c+/.

Table 3 (Weight %) Table 4 In Table 4 above, strength indicates compression strength and is the average value of five samples, and the unit is kg/cd.

The bulk specific gravity of these 13 samples was 5.40 for No. 1, and 5.46 for No. 2 to No. 13.

Next, in order to find the optimum value of the binder density, we varied the amount and measured the compression strength and drop test conditions.
．． They are shown in Table 7.

Table 5 Table 6 (Binder, 0.8% by weight of Hp-300OA added) Table 7 (Binder, 0.3% by weight of kerosene.

(Addition of 0.8% by weight of Hp-300OA) Next, the binder was changed and the results of a heating melting test of the molded product in an electric furnace are described below.

b) Observation results from heating to melting No. 5 shown in Table 5. No, 9. No, 14+N
o, 18 specimens were placed in a clay crucible and silicone 1. The specimens were heated in an electric furnace (oxidizing atmosphere) and poked with an iron rod at approximately 100°C to check whether they would break or not.

At approximately 300°C, the surface of the specimen appears to be slightly softened and bubbly, similar to the softening of synthetic resins, but no smoke or combustion phenomena are observed, and even when poked with a stick up to 1350°C, no bubbles appear on the surface of the specimen. It doesn't stick and is very hard. However, 1430℃
Dissolution started from the surface and side parts, and everything was dissolved.

In addition, No. 5.
No, 9°No, 14. 5 each of No. 18 specimens
Although 0 g was added at a time, no breakage was observed, and the solution was dissolved in about 2 minutes while moving slightly in the hot water.

Mouth) Results of dissolution yield test: Approximately 500g of specimen was placed in a clay crucible and heated to 1200℃2.
After heating for 5 minutes, the mixture was held at 1500° C. for 5 minutes, taken out of the furnace and cooled in air, and the melting yield was measured and is shown in Table 8.

(8) Particularly, since the resin polymerizes and coats the surface of the minute metal, it is less likely to be oxidized, and the dissolution yield also improves.

Next, an example will be shown in which it is actually used as a raw material for steel manufacturing.

<Example 1> Put RMzst into a hopper with a pay roller, take it out with a baby conveyor, weigh 500 kg each, and put it in the play ME.
Add binder Hp-30 to the mixer and stir while stirring.
Pour 40kg of 0OA, stir for about 3 minutes, then cut into the hopper in front of the molding machine, put about 8kg into the rotary cylindrical form (13emfX 30cm) of a 5oot press, and compression mold at 3.5t/cwt. Then, after being rotated, it was successively molded using an extrusion method, and after curing (drying) in the air for about 5 to 6 days, it was hung with a riff mug and loaded onto a truck, where it was used as a raw material for steelmaking.

<Example 2> After weighing grains @ 250 kg each, on a baby conveyor,
Pour into a small planetary mixer and add 0.70- kerosene while stirring.
After stirring for about 2 minutes, add binder Hp-
After adding 0.125 kg of 100OA, it was stirred for 3 minutes, taken out to a popper in front of the briquette machine, and continuously molded using a high pressure briquette machine (hole type, 33X33X12 ceramic wire pressure, 3t).
After curing (drying) in the air for about 5 days, it was hung with a riffmag similar to Example 1, loaded onto a truck, and used as a raw material for chain making.

In addition, a comparative test was carried out by a steel manufacturer using the molded products of Examples 1 and 2 using the same amount of mold pig iron, and there was no difference in superiority or inferiority, and there were no problems.

Before use, a drop test was carried out on steelmaking raw materials or in a scrapyard where the product was hung from a riff mug and dropped from about 4 to 5 meters without any problems.

Note that the molded product may be cured in air for 4 to 7 days, but
If heat of about 50° C. to 100° C. is used, the curing polymerization time will be very fast, and sufficient strength can be obtained within about 3 hours.

As described above, according to the present invention, minute metals such as two grains of iron, dust, and minute abrasive powder can be easily agglomerated at room temperature, and the amount of binder used can completely eliminate the voids between the minute metals. Since the surface of the minute metal is completely coated, no additional energy is required for drying or agglomeration, and the binder used is also inexpensive, requiring only a small amount, resulting in low manufacturing costs. The resulting product has a low binder content, so the metal quality is high, and the surface is V1111! Since the product is coated with molten metal, it will not rust, and since there is little empty space in the product, it will not contain air and will not cause bumping even if it is poured into molten metal. Furthermore, the product of the present invention has a high compression strength and high drop strength, so when it is thrown into molten metal for convenience, it has the excellent effect of causing a sufficient reaction with the molten metal, making it useful as a raw material for steelmaking and as a coolant. It is something.

Patent applicant: Japan Magnetic Separation Co., Ltd. Agent Noriharu Ariyoshi C-

Claims (1)

[Claims] 1. Adding 0.5 phenolic resin binder to minute metal
A method for molding minute metals, which comprises adding ~1.0% by weight and then mixing to form a lump. 2. Add 0.4 phenolic resin binder to minute metal
~0.7% by weight and 0.2~0.5% of heavy oil or kerosene
A method for forming fine metals, which is characterized by adding % by weight and then mixing to form a lump.