JP2732898B2 - Agglomeration method of powdered metal - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial application field] The present invention is intended to effectively use iron ore powder or granular metal particles recovered from various slags for washing, steelmaking raw materials and the like. And a method for providing a water-resistant, easy-to-handle form.

[Conventional technology]

A fibrous or linear material can be easily agglomerated because it can be agglomerated simply by compression molding, but finer granular metal cannot be agglomerated by simply compressing it.

As a method of agglomerating such fine and granular metal, the following method is generally used.

That is, a method using an inorganic binder such as cement or bentonite.

A method using polyvinyl alcohol or carboxymethyl cellulose.

Method using starch.

Method using molasses, tar, ethylene bottom.

A method using a polyurethane-based thermosetting resin.

A method using a phenolic resin.

Etc.

[Problems to be solved by the invention]

The above-mentioned methods have various problems, and their improvement has been strongly desired.

That is, the method of (1) reduces the amount of binder to about 10% by weight (hereinafter simply referred to as%
Abbreviated as "), and the amount of binder is increased by kneading after adding water and kneading, whereby the quality of the metal is reduced and the S content is increased by sulfur (S) contained in the binder. In addition, in the case of powdered and granular metal to which oil adheres, the adhesion of the binder is poor and the solidification strength in the normal state does not increase. Is required. In addition, since this method is hardened by hydration reaction, its drop strength is small, it is easily broken or broken, and handling is inconvenient. Effect is not sufficiently exhibited.

The next method is a method of adding and mixing about 0.5% of a binder and water, and mixing and molding. However, if fats and oils are adhered, they do not cure, so they are also removed by burning using a kiln or other means. Oil and fat must be removed.

This method causes the same problem as the method using β-type starch.However, when α-type starch is used, agglomeration is relatively easy and the solidification strength is normal, but the water resistance is poor. Therefore, there is a drawback that the agglomerates cannot be stored outdoors.

Further methods have the same problems as
The working environment is significantly impaired in terms of odor.

Another method is to heat the raw material to 180 to 200 ° C., add 1 to 5% of a binder and mix and mold the mixture. Since the binder is expensive and the raw material to which the oil adheres, the oil is vaporized at the time of heating, There are disadvantages such as the need to use a special device such as a kiln.

In addition, the method of (1), although the water crush resistance after the heat treatment is remarkably good, it is difficult to agglomerate because the normal strength is weak,
The agglomerate is broken in the deburring machine and is difficult to handle.

[Means for solving the problem]

In the present invention, the above-mentioned problems are solved, and even if the raw material to which the fats and oils are attached is inexpensive and can be easily agglomerated, and as a result of intensive studies on a method for imparting water resistance,
It was found that more favorable effects could be obtained by adding, mixing, and press-molding an organic natural product and a thermosetting resin, followed by heat treatment, and completed the present invention.

That is, the present inventors consider that organic natural products
The present invention relates to a method for agglomerating powdery and granular metal, which comprises adding, mixing, and press-molding a mixture of 0.1 to 10% and a thermosetting resin of 0.1 to 5%, followed by heat treatment.

[Detailed Disclosure of the Invention]

 The present invention will be described more specifically.

The fine-grained metal used in the present invention refers to fine-grained iron ore and fine-grained metal recovered from various slags.

The organic natural product contains at least starch in the components, and the content of the starch is not particularly limited. Such organic natural products may be wheat flour, barley flour, rye flour, flying flour, starch, or a mixture thereof.

The addition amount of the organic natural product is 0.1 to 10 with respect to the granular metal.
% Is appropriate, preferably 0.5 to 5%. If it is less than 0.1%, the moldability is poor, and the molded article is brittle and fragile due to low normal strength. Conversely, if it exceeds 10%, the water resistance is remarkably reduced, and the dissolution loss during outdoor storage is large, which is not advisable.

Next, examples of the thermosetting resin used in the present invention include urea resins, melamine resins, phenol resins, and co-condensation resins thereof.

The urea resin used is one obtained by condensing formaldehyde (F) and urea (U) at a molar ratio of F / U of 1.0 to 3.0, and the melamine resin is formaldehyde (F)
And melamine (M) are condensed at a ratio of 2.0 to 3.5 as F / M, and the phenolic resin has a formaldehyde (F) and phenol (P) mole ratio of F / P
Those condensed at a ratio of 1.0 to 3.0 are used. Also,
These resins may be co-condensed or simply mixed and used.

These amino resins are polyvinyl alcohol,
Those modified with a modifying agent such as carboxymethyl cellulose and hydroxyethyl cellulose are preferred. The reason is that amino resin having appropriate viscosity and tackiness can be obtained by modifying, so that the modified amino resin can impart strong normal consolidation strength between powder metal particles. is there.

The amount of these resins to be added is 0.1 to 5%, preferably 0.5 to 3%, as a resin solid content, based on the powder metal. If it is less than 0.1%, a significant decrease in water resistance is caused, and conversely 5%
Exceeding the above results in a molded article having a weak strength immediately after molding, which is liable to breakage, and also raises the cost, which is economically disadvantageous. The amount of the resin added is calculated on a solid content basis.

These amino resins can be used alone or in combination,
Since the amino resin generally has a solid content of 40 to 80%, it may be diluted with an appropriate amount of city water. The amino resin has a pH value in physical properties of 7 or more measured by a pH meter from the preservability of the resin, and is kneaded together with the organic natural product and the granular metal because it is in an alkaline region. The starch in the organic natural product is gelatinized by the alkali properties of the amino resin, so that the cohesive force can be further increased, so that the moldability is good and the handling becomes easy.

In the present invention, it is an essential requirement to use an organic natural product and a thermosetting resin in combination, and by satisfying this requirement, not only the moldability but also the normal consolidation strength immediately after molding is remarkably improved, and handling in the subsequent steps The loss can be reduced, and a great economic effect can be expected.

The thus obtained kneaded material is subjected to heat treatment after being subjected to pressure molding, so that a stronger fixing strength can be obtained.

The pressure for the pressure molding is carried out by applying a pressure of 0.1 to 5 t / cm ^{2 by} a compression tester, but is preferably carried out at a pressure of 1 to ³ t / cm ² . If the pressure of the pressure molding is less than 0.1 t / cm ² , strong fixing strength cannot be obtained and the density is not sufficient. If it exceeds 5 t / cm ² , both the adhesive strength and the density are sufficient, but it cannot be said that it is preferable for maintenance of the compression tester, and it is economically lossy.

The pressurization time depends on the type and amount of the organic natural product and the thermosetting resin to be used, the molding pressure, and the like, but is usually from 1 second to 30 seconds.

The heat treatment temperature is usually from 50 to 200 ° C, but preferably from 100 to 150 ° C. If the pressurizing temperature is lower than 50 ° C, the curing of the amino resin will be insufficient and sufficient water resistance and fixing strength will not be obtained.On the other hand, if it exceeds 200 ° C, the decomposition of the amino resin will be promoted and it will be used as a binder. Cannot be effective.

The heat treatment time depends on the heat treatment temperature and the pressure of pressure molding, but is usually 10 to 40 minutes.

(Examples and Comparative Examples)

Hereinafter, the present invention will be specifically described with reference to Examples and Comparative Examples.

Example 11 Three stainless steel containers were prepared, and 500 parts by weight (hereinafter simply abbreviated as "parts") of powdered iron as shown in Table 1 were added thereto. After adding 2.5 parts, 10 parts and 17.5 parts of Nisshin Flour Red Flower, respectively, and mixing well, urea resin (Euroid U-70 manufactured by Mitsui Toatsu Chemicals, Inc.) was added.
(1 solid content 50%) was slowly added to 7.5 parts of each, and mixed well for about 10 minutes to obtain a mixture. The mixture is 30 m in diameter
130 g was placed in a mold having a height of 60 mm and a height of 60 mm, and the mixture was pressurized with a compression tester from above at a pressure of 1.0 t / cm ² for 20 seconds to obtain a molded product of the mixture. As a result, a cylindrical specimen having a diameter of 30 mm, a height of 35 mm, and a density of 5.2 g / cm ³ was obtained. The above operation was repeated three times, and three cylindrical specimens were obtained under the same test conditions, for a total of nine specimens. A specimen was obtained. 9 specimens
After being placed in a dryer at 110 ° C. and left for 20 minutes to perform a heat treatment, the product was taken out of the dryer to obtain a molded product. As a result of evaluating various physical properties of the molded product, it was as shown in Table 2.

From the results, the crushing, water resistance, hot and drop strength were both satisfactory and practically sufficient.

The values of the evaluation results in Table 2 are all results of the average value of three molded articles.

Examples 2 to 4 According to the method of Example 1, a thermosetting resin and an organic natural product were added and mixed in the amounts shown in Table 2 to obtain a mixture. The mixture was subjected to heat treatment at the heat treatment temperature and time shown in Table 2 to obtain a molded product. As a result of evaluating various physical properties of the molded product, it was as shown in Table 2.

As a result, as in the case of Example 1, the crushing, the water resistance, the hotness, and the falling speed were satisfactory, and the material was sufficiently practical for use as a raw material for steelmaking.

Comparative Example 1 7.5 parts of starch (Japanese corn starch) and 5 parts of city water were added to and mixed with 500 parts of the granular iron in the same manner as in Example 1, and mixed in the same manner as in Example 1. The heat treatment was performed at the heat treatment temperature and time shown in (1) to obtain a molded product.
As a result of evaluating various physical properties of the molded product, it was as shown in Table 2.

Comparative Example 2 The same powdery and granular iron as in Example 1 was used, and 500 parts of the powdery and granular iron were mixed with 10 parts of a phenolic resin (HP-3000H) and mixed in the same manner as in Example 1 to obtain the heating shown in Table 2. Heat treatment was performed at the treatment temperature and time to obtain a molded product. As a result of evaluating various physical properties of the molded product, it was as shown in Table 2.

Comparative Example 3 7.5 parts of a urea resin and 60 parts of flour (red flower) were added to 500 parts of the granular iron using the same granular iron as in Example 1, and mixed.
In the same manner as in Example 1, heat treatment was performed at the heat treatment temperature and time shown in Table 2 to obtain a molded product. As a result of evaluating various physical properties of the molded product, it was as shown in Table 2.

As shown in Table 2, the results of Comparative Examples 1 to 3 show that both the crushing strength and the hot strength are smaller than those of Examples 1 to 4, and that the water resistance is greatly reduced, which is fatal and not practical.

Note-1) The strength measured with an Olsen universal testing machine immediately after molding. The compression strength was measured at a compression speed of 6 mm / min. Hereinafter, measurement was performed under the same measurement conditions.

Note-2) The molded product was cured at room temperature for 3 days and then in city water (20 ° C).
Compressed strength measured by Olsen universal tester after immersion for 24 hours.

Note-3) Compressive strength of the molded product after curing at room temperature for 3 days, placing it in an electric furnace at 400 ° C for 10 minutes, burning it out, cooling it to room temperature and immediately measuring it with an Olsen universal testing machine.

Note-4) Drop on a steel plate with a thickness of 20 mm from a height of 2 m. ◎: Not damaged ○: Partly damaged part in contact with iron plate ×: Partly damaged in part in contact with steel plate Divide by ~ 1/2.

〔The invention's effect〕

As described in detail above, the present invention is a method for agglomerating a granular metal. The present invention uses an organic natural product and a thermosetting resin in combination as compared to conventional binders, and furthermore, by performing a heat treatment, a higher degree of water resistance can be obtained. Is no longer necessary, saving significant construction costs.

Since an excellent powdery or granular metal which can significantly improve the normal strength immediately after molding can be obtained, an improvement in the yield in the post-process can be greatly expected.

In addition, the agglomerate formed by the method of the present invention has high strength, and does not cause bumping even when it is directly poured into the molten metal, and since the surface is coated with a resin, the metal or the like is not used. Has the effect that it does not rust.

Claims (3)

(57) [Claims] An organic natural product in an amount of 0.1 to 10 with respect to a granular metal.
A method for agglomerating a powdery or granular metal, comprising adding, mixing, and press-molding a mixture of 0.1% to 5% by weight of a thermosetting resin, followed by heat treatment. 2. The organic natural product is selected from the group consisting of wheat flour, barley flour, rye flour, flying flour, and starch flour.
The described method. 3. The thermosetting resin is a urea resin, a melamine resin,
The method according to claim 1, wherein the method is selected from the group consisting of phenolic resins and co-condensation resins thereof.