KR940007139B1 - Electric wave absorbent - Google Patents

Abstract

The radio wave absorber produced by dispersing dust of electric furnace of steel-making factory and inorganic materials into a binder is provided. Also, a radio wave absorber produced by dispersing dust of electric furnace, inorganic material and one or more divalent metal in a binder is provided.

Description

[Name of invention]

Radio wave absorber

[Detailed Statement of Invention]

The present invention relates to a radio wave absorber, and more particularly to a radio wave absorber using an electric dust and inorganic materials.

Radio wave absorbers cause radio interference such as radio waves from electronic devices, which recently increased rapidly, leak out of electronic devices, causing malfunctions of other devices, and adversely affect the human body and animals and plants. Since the radio waves are reflected from large structures, tanks, large vehicles, and buildings, it has been used to prevent crosstalk of various radio waves or military targets.

In order to absorb the radio wave, a carbon wave absorber using a conductive loss, a wave absorber using a dielectric loss and a ferrite wave absorber using a magnetic loss have been known, and in recent years, a carbon ferrite wave absorber combining the above conductive loss and magnetic loss has been known. There has been much progress in its thickness and radio absorption capability.

However, ferrite, which is a magnetic loss material used in the ferrite wave absorber and the carbon ferrite wave absorber, is a general formula MO · Fe ₂ O ₃ (where M is a divalent metal such as manganese, nickel, copper, zinc, magnesium, and cobalt). As can be seen, the ferrites synthesized with the metal oxides used here are expensive, and iron oxides obtained by treating acid-cleaned wastewater generated in steel mills, plating plants, etc. may be used in combination with other metal oxides. It is not satisfactory in terms of price because it separates and uses the included pickling wastewater, and there is a lot of room for improvement in the radio absorption ability, in particular, a narrow bandwidth.

As a result of many tests and studies on the above-mentioned radio wave absorber, the present inventors found that there are problems such as magnetic materials (ferrite), dielectric materials, and conductive materials, which are currently used for radio wave absorption.

In other words, the high frequency loss materials currently used, for example, magnetic materials, are used to select the highest purity of the principal component compounds to increase the initial permeability and minimize the magnetic loss. Therefore, the lower the magnetic loss, the better the performance. Although it is suitable for use, it has been found that a radio wave absorber for the purpose of improving the radio wave absorbing capacity and the expansion of the frequency bandwidth exhibits a good performance when the high frequency loss is large, and thus is not suitable for use as a radio wave absorber.

However, high frequency loss materials known to date have been developed for use in cores and the like, so making a radio wave absorber using them is indispensable, that is, the radio wave absorption capacity, thickness, and major fruit bandwidth are not satisfactory.

SUMMARY OF THE INVENTION In view of the above facts, an object of the present invention is to provide a radio wave absorber having an improved radio wave absorption capability, a wider frequency bandwidth, and an economical radio wave absorber by mixing the steelmaking dust and steel materials for steelmaking.

The present invention is characterized in that the steelmaking electric dust and inorganic materials for steelmaking are dispersed in a binder or at least one divalent metal and a conductive loss material or dielectric loss material are added.

The present invention considers the principle of improving the radio-absorption capacity of the electric dust, and by forming a multi-radiation structure by the radiopaque inorganic material to increase the loss of radio waves, the radio wave absorption capacity is improved, to obtain a radio wave absorber having a wide frequency band Can be.

The chemical composition of the electric furnace dust for steelmaking used in the present invention is as shown in Table 1, it has a crystal structure of spinal ferrite, it is generally difficult to treat it as a waste, only the foreign matter other than dust that is recovered from the dust collector Use separately.

TABLE 1

In addition, the inorganic material used in the present invention is used as a ceramic material, such as silica sand, kaolin, feldspar, clay, bentonite, chamotte, zircon sand, eu kryptite, cordierite, olivine, steatite, mulite, petarite and waste One or more kinds of industrial waste pulverized materials such as pottery are used, and as the conductive loss material, well-known ones such as carbon powder, graphite, carbon black, and carbon fiber are used, and dielectric loss materials such as barium titanate can also be used.

In addition, at least one of the above-mentioned divalent metals added in the present invention is also used, and the composition ratio, the particle size and quantity of the inorganic material, etc. are designed and changed according to the frequency characteristics of the radio waves absorbed and deteriorated. In addition, a known inorganic binder and an organic binder (including a vehicle for coating) are used as the binder, and the above-described inorganic materials can be used as the binder.

It demonstrates by an Example below.

Example 1

70g of electric furnace dust for steelmaking (chemical composition is shown in Table 2) and 30g of commercial Cordierite powder manufactured by Dairy Industries Co., Ltd. are dispersed in 20g of polypropylene resin to make 2.4mm thick plate. As a result of measuring the radio absorbance at GHz, the attenuation characteristic was obtained up to -15dB.

TABLE 2

Example 2

60 g of iron oxide, 20 g of magnesium oxide, 20 g of kaolin powder, and 10 g of clay were uniformly mixed with 60 g of the same electric furnace dust as in Example 1, and made into a 6 mm thick tile, fired at 1350 ° C., and then radio wave absorption capacity was measured using a network analyzer. The reflection attenuation of -24dB in the frequency S-band was obtained.

Example 3

6 g of graphite powder was added to the same composition ratio as in Example 1 to form a 2 mm plate, and the electron absorption capability was measured at 2.45 GHz as a network analyzer, thereby obtaining a maximum amount of reflection attenuation of -20 dB.

Example 4

9 g of graphite powder was added to the same composition ratio as in Example 2 to form a tile having a thickness of 5.6 mm, and the reflection attenuation was measured using a network analyzer. A reflection attenuation was obtained over a frequency range of 2.5 GHz to 5.5 GHz. It was -18dB and -18dB attenuation bandwidth reached 0.7GHz.

Example 5 (Comparative Example 1)

75 g of Mn-Zn ferrite powder and 25 g of polyethylene resin were uniformly mixed to form a plate with a thickness of 2.4 mm. As a network analyzer, radio wave absorbing capacity was measured at a frequency of 2.45 GHz.

Example 6 (Comparative Example 2)

70 g of Ni-Zn ferrite powder and 9 g of graphite powder were uniformly mixed with 25 g of polypropylene resin, and then made into a plate having a thickness of 2 mm, and the radio wave absorption capacity was measured at a frequency of 2.45 GHz using a network analyzer.

As can be seen in the above embodiment, by uniformly mixing and dispersing the electric dust and the inorganic material in the binder, the multi-radiation structure is added to the electric wave absorbing ability of the electric dust to increase the loss of electric wave, thereby improving the electric wave absorbing ability. It is possible to obtain a radio wave absorber with a wide bandwidth, and is economical by utilizing waste, and contributes to preventing pollution, and also has a simple effect on the production process.

Claims (5)

Electric wave absorber which disperse electric furnace dust and inorganic material of steelmaking plant in binder. The radio wave absorber according to claim 1, wherein a loss member selected from a conductive loss member and a dielectric loss member is added. The radio wave absorber according to claim 1, wherein the inorganic material and the binder are the same. An electric wave absorber in which electric furnace dust, an inorganic material, and one or more divalent metals in a steel mill are dispersed in a binder. The radio wave absorber according to claim 4, wherein a loss member selected from a conductive loss member and a dielectric loss member is added.