JPS6396202A - Production of dustproof active metal powder - Google Patents

Abstract

PURPOSE:To produce active metal powder which is improved in dustproof and explosionproof characteristics by adding and mixing a specific amt. of particulate PE glycol to and with raw material grains of an active metal in the stage of crushing and subjecting the mixture to dry pulverization to a specific grain size in an inert gaseous atmosphere. CONSTITUTION:The dustproofing agent of the particulate PE glycol and/or PE oxide is added and mixed at 0.01-0.5pt.wt. to and with 100pts.wt. raw material grains of the active metal formed to about <=15mm grain size in the stage of the crushing. The active metal includes Ca, Mg, Al, Si, Zr, Ti, Fe, etc. The mixture is then subjected to the dry pulverization continuously in the inert gaseous atmosphere so that >=50% thereof is <=100mesh fine powder. The fine dustproof powder which is eliminated of the danger for dusting and exploding during handling is thereby obtd. at a low cost without deteriorating the characteristics of the active metal powder.

Description

[Detailed description of the invention] [Industrial application field] The present invention is a deoxidizing agent for steel manufacturing, a refractory additive, and a paint.

Reaction catalyst, metal refining 1 exothermic agent, fireworks,? 8 contact rod etc. are widely used such as Ca, Mg, A7. Si, Zr, Ti
The present invention relates to a method for producing active metal powders such as Fe or their alloys with improved dust and explosion resistance without compromising any of their properties.

[Conventional technology]

When manufacturing these active metal powders, atomization processing or mechanical pulverization using impellers, stamps, ball mills, etc. are often used, so explosion-proof measures are extremely important in addition to dust-proofing.

Conventional dust-proof and explosion-proof measures taken when processing active metal powders with strong oxidizing power include processing them together with liquids such as oil and ethylene glycol, or treating these liquids with F! I! It was common practice to thoroughly impregnate the powder.

However, depending on the purpose of use, there may be cases where it is desired to use it as a dry powder.
As described in Japanese Patent Publication No. 877 and Japanese Patent Publication No. 55-24481, there is a method in which active metal powder is mixed with granular polytetrafluoroethylene (PTFE) resin.

[Problem that the invention seeks to solve]

The above-mentioned PTFE is excellent as a dry powder dustproofing agent, but it is expensive in itself, and it is added when the crushing is completed, so it is difficult to obtain the fine powder in the process of obtaining the fine powder. There is a high risk of dust explosion.

The purpose of the present invention is to find a dustproofing agent that is cheaper than PTFE, the conventional dustproofing agent, and to use this dustproofing agent to improve the properties of active metals without affecting the properties of active metals in the pulverization process. To provide a method for producing dust-proof active metal powder that can avoid the danger of three dust particles.

[Means for solving problems]

As a result of various trials and errors, the present invention has found that while powdered polyethylene glycol and polyethylene oxide are cheaper than PTFE, the above object can be achieved by specifying the conditions for their addition.

That is, in order to reduce the risk of dust explosion up to the stage of pulverization that can be dust-proofed, granular polyethylene glycol or polyethylene oxide is added and mixed to the coarsely crushed active powder at the stage of coarsely crushing the active metal, and further, This is a method that makes the raw material dustproof while pulverizing it in an inert gas atmosphere.
This enables the use of an inexpensive dust-proofing agent in place of PTFH, and has succeeded in developing dust-proofing effects in parallel with the progress of explosion-proof crushing without having the same negative effect on the properties of active metals by adding a small amount. .

Of course, granular polyethylene glycol or polyethylene oxide as dustproofing agents can be used in combination with each other or with other dustproofing agents.

Furthermore, in the present invention, by simultaneously adding solid fatty acids such as stearic acid or saponified products thereof together with polyethylene glycol or polyethylene oxide, in addition to the effect of adding polyethylene glycol or polyethylene oxide at the above-mentioned crushing stage, powder It is possible to increase the yield of powder by reducing adhesion to the grinder and agglomeration of particles among themselves.

In terms of explosion protection, it is most efficient if the diameter of the particles in the coarse crushing stage of the active metal at the stage of adding dustproof agent powder such as polyethylene glycol or polyethylene oxide is 15+U or less. 10
The pulverization efficiency is too low to obtain a fine powder with a mesh size of 0 or less. The preferred particle size of the raw material depends on the crusher selected, but for crushers such as impellers, stamps, and ball mills, a particle size of 3 mm or less is most economical.

Next, regarding the amount of powdery polyethylene glycol and/or polyethylene oxide that is a dustproofing agent, 0.00% of the powdery and granular material is added to 100 parts by weight of the coarsely crushed active metal raw material.
It is sufficient to use 01 to 0.5 parts by weight, and the appropriate amount to be added varies somewhat depending on the type of grinding machine and grinding conditions.

Normally, if it is less than 0.01 part by weight, the dustproof effect is weak, and if it is less than 0.01 part by weight,
If the amount exceeds 1 part by weight, the adhesion and cohesive force will be so strong that discharge and classification will become difficult or impossible.

In addition, if 0.05 to 0.5 parts by weight of a solid fatty acid such as stearic acid or its saponified product is added in order to improve the problem, the dust-proofing effect of the dust-proofing agent will not be affected and the adhesion to the crusher will be reduced. Furthermore, it is possible to effectively prevent particles from agglomerating together, thereby improving the yield of treated powder.

Furthermore, regarding the pulverization conditions, in the method of the present invention, it is sufficient to continuously dry-pulverize the coarsely crushed raw material of 15 ryu or less and obtain 50% or more of 100 mesh or less, and thereby,
It is possible to obtain active metal fine powder that has a sufficient dust-proofing effect.

However, under a scanning electron microscope, the added dustproofing agent and the fatty acid or its saponified product, which will be described later, cannot be clearly identified in the active metal powder aggregate, which has a remarkable dustproofing effect, and the mechanism thereof is also unclear.

Note that there is no particular limitation on the amount and timing of addition of the dustproofing agent, and it is sufficient that the time required for the dustproofing agent to be dispersed throughout is sufficient.

Regarding the classification process, it is not necessary to use a crusher that is equipped with the mechanism, but in the case of unclassified products to be crushed, it is sufficient to classify them according to the target particle size.
It is possible to classify with a sieve mesh down to the mesh level. Since this work is dust-free, it is environmentally friendly and can be carried out safely.

The obtained dust-proof powder has a single particle size of 60 mesh or less, exhibits a rounded granular shape, and a WE aggregate coarse secondary particle size formed by weak adhesion of these particles, which is 60 mesh or less, and 98% or more of the mesh is 100 meshes or less.

〔Example〕

Example 1゜AI and Mg with a purity of 99% or more? A homemade alloy ingot with a weight ratio of 0.1% A1 and 48.9% Mg was crushed using a small show crusher to a diameter of 1011 mm or less to prepare a crushed raw material. Next, the AAl-1I alloy coarse raw material 2k
tr, polyethylene oxide powder manufactured by Meiwa Kasei Kogyo Co., Ltd. (trade name Alcox R150) was used as a dustproofing agent.
) was placed in a magnetic bot mill with an internal volume of 1i, nitrogen gas was charged, and dry pulverization was carried out for 10 hours. Next, 1.82 kg of the obtained material to be crushed was classified using a 100-mesh sieve, and
1.60 kg of a powder product of 0 mesh or less was obtained. Tjl for comparative flow test Y! It was found to be dust-free when measured.

Example 2 A1. with a purity of 99% or more. l! A homemade alloy ingot having a weight ratio of 50.7% Af and 48.0% Mg obtained by welding 1 g of :r' was crushed to a size of 101 diameter or less using a small show crusher to prepare a coarsely crushed raw material. Next, polyethylene oxide powder manufactured by Meiwa Kasei Kogyo Co., Ltd. (trade name Alcox R1) was added to 2 kg of the AI Mg alloy coarse raw material as a dustproofing agent.
50) 10g and 4g of granular stearic acid in an internal volume of 14
Place it in a I2 porcelain pot mill and charge nitrogen gas for 10 minutes.
Dry milled for an hour.

Next, 1.90 kg of the obtained material to be crushed was classified using a 100-mesh silk sieve, and powder products with a size of 100 mesh or less were classified by 1.90 kg.
I gained 80kg. The resulting product with a size of 100 meters or less was dust-free in a comparative flow test. This yield was improved over that of Example 1.

Example 3゜The same homemade alloy ingot as in Example 1 was treated in the same manner as Ion.
The raw material was coarsely crushed to a size smaller than the diameter, and a coarsely crushed raw material was prepared. Next, the At-
To 2 kg of Mg alloy coarse raw material, Sanyo Chemical Industries Co., Ltd. polyethylene glycol powder with molecular weight ff11200 was added.
and 4 g of granular stearic acid were placed in a porcelain pot mill with an internal volume of 14 e, and nitrogen gas was introduced into the pot mill for dry pulverization for 4 hours.

Next, 1.90 kg of the obtained material to be crushed was classified using a 100 mesh sieve, and products with a size of 100 mesh or less were classified by 1.82 kg.
I gained kg. It was found to be dust-free when measured according to Comparative Flow Test Y.

This yield was improved over that of Example 1.

Comparative Example Grinding was carried out in the same manner as in Example 3 under the same conditions except that polyethylene glycol was removed.

Similar to Example 3, 1.91 g of the crushed material, which corresponds to almost the entire amount, was discharged from the pot mill, but a large amount of dust was generated during discharge. The yield of a product of 100 mesh or less obtained in the same manner as in Example 3 was 1.65 kg, but in a comparative flow test, it had no dust resistance at all.

〔Effect of the invention〕

By using the dry process of the present invention to process the pulverization and dust-free treatment of coarsely crushed raw materials in the same process, the amount of dust-proofing agent used can be reduced and the properties of the active metal powder can be maintained without deteriorating to the same extent as in the manufacturing process. It is possible to obtain e=W powder which can completely prevent dust explosion and eliminates the risk of dust explosion during handling.

Claims (1)

[Claims] 1. Add and mix 0.01 to 0.5 parts by weight of a dustproofing agent of granular polyethylene glycol and/or polyethylene oxide to 100 parts by weight of active metal raw material grains at the coarse crushing stage to form an inert powder. A method for producing a dust-proof active metal powder, which comprises continuously dry-pulverizing the powder in a gas atmosphere until at least 50% of the powder has a particle size of 100 mesh or less. 2. Add 0.01 to 0.5 parts by weight of a dustproofing agent of granular polyethylene glycol and/or polyethylene oxide to 100 parts by weight of active metal raw material particles at the coarse crushing stage, and 0.05 to 0.5 parts by weight of a solid fatty acid or its saponified product. 1. A method for producing a dust-proof active metal powder, which comprises adding and mixing parts by weight and dry-pulverizing continuously under an inert gas atmosphere until 50% or more of fine powder of 100 mesh or less is obtained.