JP5762335B2 - Dezincing equipment - Google Patents

Description

  The present invention relates to a dezincing apparatus that heats a galvanized steel sheet to evaporate and remove zinc.

  2. Description of the Related Art Conventionally, in the casting industry, the proportion of scrap steel plates that are melted into raw materials for cast iron has increased, and galvanized steel plates are typical of scrap steel plates that are reused. An electric furnace melting method is commonly used as a means for melting scrap steel plates, but there are various problems when melting galvanized steel plates. For example, if a galvanized steel sheet is melted as it is, zinc penetrates and passes through the furnace refractory, damages the heating coil, shortens the life of the melting equipment, and increases maintenance costs. In addition, zinc has a low boiling point and easily evaporates, which may lead to deterioration of the working environment due to zinc vapor, and may deteriorate the quality due to zinc being mixed into the product.

  Therefore, an induction heating type dezincing apparatus as shown in Patent Document 1 has been proposed. According to this induction heating type dezincing apparatus, the zinc coil is melted by energizing the heating coil by inductively heating the galvanized steel sheet, and the zinc white produced by evaporation of a part of the molten zinc is externally discharged from the material discharge port. Can be exhausted.

  However, in the induction heating type dezincing apparatus described above, heat does not reach the galvanized steel sheet located in the center of the heating cylinder, and the zinc is not sufficiently removed and conveyed to the induction melting furnace in a state where zinc is oxidized. Zinc may be mixed into the product. In particular, the zinc during processing is easily oxidized when exposed to the atmosphere. When zinc oxide is generated on the surface of the steel plate scraps with a distorted shape, the zinc oxide powder accumulates and is applied to a sieve or applied vibration. However, it cannot be easily removed. In addition, the sublimation point of zinc oxide is about 1725 ° C., which exceeds the melting point of iron (about 1535 ° C.), and it is difficult to volatilize and remove zinc oxide with the above apparatus.

  For such a problem, a dezincing device of Patent Document 2 has been proposed. According to this dezincing device, a hollow alloy steel pipe standing at the center of the induction heating vessel is heated to heat the galvanized steel plate near the center of the vessel, enabling uniform heating in the vessel. Yes.

JP-A-8-83676 JP 2011-42850 A

  However, the dezincing apparatus of Patent Document 2 has a problem that the amount of dezincing treatment of the galvanized steel sheet is limited. If the container is enlarged to increase the throughput, sufficient heat is not transferred to the galvanized steel sheet located away from the heating coil on the outer periphery of the container and the heating source of the hollow pipe in the container, making uniform heating difficult. This is because there is a risk of becoming.

  In addition, in the heating by the heating coil on the outer periphery of the container and the hollow pipe in the container, if a galvanized steel sheet having greatly different attributes such as size, mass, and shape is introduced, all these uniform heating becomes difficult. is there. For example, if a small galvanized steel sheet is introduced near the heating source and a large galvanized steel sheet is introduced away from the heating source, there is a difference in the degree to which both are heated. Since the galvanized steel sheet subjected to the dezincing process is scrap, the size and mass of each individual are different, and in particular, the shape that affects the heat transfer is often different, which can be a factor that inhibits soaking in the container. .

  In order to solve these problems, it is conceivable that the container is rotated and the galvanized steel sheet is stirred so as to equalize the temperature in the container. However, since a heating coil or the like is provided, it can be said that rotating the container is difficult in terms of equipment configuration. Moreover, even if it can be agitated, since an induced current flows through the galvanized steel sheet, a spark discharge is generated by contact between the steel sheets, and a new explosion such as a small explosion of gas in the container or fusion between the steel sheets. Cause problems.

  Therefore, the present invention has been made in view of the above problems, and provides a dezincing apparatus that can cope with an increase in throughput and can achieve uniform heating regardless of the attribute of the galvanized steel sheet. The purpose is to do.

  In order to solve the above-described problems, a dezincing apparatus according to the present invention includes a cylindrical heating container having an opening for charging a galvanized steel sheet, a rotation driving unit that rotates the entire heating container, and the heating Arc generating means for generating an arc for heating the galvanized steel sheet by means of an electrode inserted from one end of the heating container on the rotating shaft of the container.

  According to this, since the galvanized steel sheet put into the container is indirectly heated by the arc while being stirred by the rotation of the container, it does not stay in a certain position. Therefore, a dezincing apparatus that can uniformly heat the inside of the container even when the processing amount is increased is realized. Moreover, since the temperature inside the container is equalized by stirring, uniform heating can be realized regardless of the attribute of the galvanized steel sheet.

  Here, the electrode is preferably a carbon electrode.

  According to this, since the carbon electrode is consumed and the CO gas is generated with the generation of the arc, the inside of the container can be made a reducing atmosphere, and generation of zinc oxide can be suppressed and efficient zinc removal can be achieved.

  Moreover, it is preferable that the electrode protection member which protects the upper direction of the said electrode is inserted on the rotating shaft of the said heating container.

  According to this, the electrode can be protected from the scratch wear of the galvanized steel sheet that falls when it is put into the container or contacts when the container rotates, and the durability of the electrode can be improved.

  Furthermore, it is preferable that the electrode is provided with an electrode swinging means that periodically and repeatedly moves the rotation axis of the heating container.

  According to this, since the generation | occurrence | production of an arc is continued by periodically perturbing an electrode during apparatus operation, it can always be made to function as a heating source.

  As described above, according to the dezincing apparatus according to the present invention, the galvanized steel sheet in the container is indirectly heated by the arc while being stirred by the rotation of the container, so that the galvanized steel sheet does not stay in one place. , Uniform heating in the container becomes possible. Therefore, even if the processing amount is increased, the temperature inside the container can be equalized, and a dezincing apparatus that can be heated uniformly regardless of the attribute of the galvanized steel sheet is realized.

It is a figure which shows the outline of a dezincification apparatus. It is sectional drawing in the AA of FIG.

  Hereinafter, a dezincing apparatus according to the present invention will be described with reference to the drawings.

  FIG. 1 is a diagram showing an outline of a dezincing apparatus, and FIG. 2 is a cross-sectional view taken along line AA in FIG.

  The dezincing apparatus according to the present embodiment is an apparatus for evaporating and removing zinc from a galvanized steel sheet using indirect heating by an arc, and includes a heating container 10 and an arc generator 12.

  The heating container 10 is a cylindrical container that heats the scrap steel plate 20 charged therein. Here, a cylindrical shape is illustrated and described as a cylindrical shape, but it may be a polygonal cylindrical body. The heating container 10 includes an opening 11 for introducing the scrap steel plate 20.

  The opening 11 can be shielded and sealed after the scrap steel plate 20 is charged. After the dezincing treatment, the opening 11 is opened again and functions as a discharge port for the scrap steel plate 20 after the treatment. In addition, it is preferable that the refractory construction is given to the heating container 10 in the whole inner surface of steel can iron skin. This is because it can be expected to prevent the dissipation of heating energy, which contributes to the soaking of the temperature in the container.

  Here, the heating container 10 is a rotation kiln type by a rotation driving means, and rotates at a constant rotation speed, for example, a speed of 5 to 15 rpm, so that the scrap steel plate 20 put into the container is agitated. It has become. As a result, the individual scrap steel plates 20 are agitated without being fixedly arranged in one place, so that it is possible to achieve uniform temperature throughout the container.

  And the arc generator 12 is provided in the one end side of the heating container 10, and it is the structure which heats the scrap steel plate 20 in a container by the indirect heating by the arc whose center temperature is about 15,000 degreeC.

  The arc generator 12 includes a bipolar carbon electrode composed of an anode 14 and a cathode 13, and an arc is generated by this electrode to act as a heating source. By using the anode 14 and the cathode 13 as carbon electrodes, the carbon electrode is gradually consumed as the arc is generated, and carbon monoxide is generated at that time. With this carbon monoxide, the inside of the container is made into a reducing atmosphere, suppressing the generation of zinc oxide, and enabling efficient zinc removal while keeping the temperature condition necessary for zinc evaporation low.

  The anode 14 and the cathode 13 are inserted in the center of the heating container 10, that is, on the rotation axis of the heating container 10. Further, as shown in FIG. 1, the member to which the anode 14 and the cathode 13 are fixed is oscillated by electric means in the direction perpendicular to the rotation direction of the heating container 10 (arrow B). That is, the anode 14 and the cathode 13 can be repeatedly moved on the rotating shaft of the heating container 10, and periodically swing during the operation of the dezincing apparatus, and always function as a heating source. The speed at which the anode 14 and the cathode 13 repeatedly move is preferably about 300 to 500 mm / min.

  Above the anode 14 and the cathode 13, a protector 15, which is a member that protects the electrode from dropping of the scrap steel plate 20 when thrown into the container and movement of the scrap steel plate 20 due to stirring of rotational motion, is installed. As shown in FIG. 2, the protector 15 is a heat-insulating refractory material because the wear-resistant layer 16 using the wear-resistant steel plate and the inner side receive heat from the electrodes in order to prevent scratch wear due to the falling scrap steel plate 20. It has a two-layer structure of a refractory layer 17 made of The protector 15 needs to cover at least the upper part of the anode 14 and the cathode 13. However, not only above the anode 14 and the cathode 13, but also as shown in FIGS. 1 and 2, the front and sides are covered to protect the electrode from abrasion caused by the stirring of the scrap steel plate 20, and the anode 14 and It is preferable to open the lower side of the electrode 13 without covering it so as not to hinder indirect heating by the arc. In FIG. 2, the shape of the protector 15 is an arc shape in order to reduce the drop impact of the scrap steel plate 20, but the cross section may be a U shape.

  A zinc vapor discharge port 18 is provided at the opposite end of the heating container 10, that is, on the opposite side of the arc generator 12. Zinc removed from the scrap steel plate 20 by indirect heating of the arc in the container becomes zinc vapor and is discharged from the zinc vapor discharge port 18 to the outside of the container by suction of the dust collector 40. Further, the degree of reduction atmosphere in the container can be determined by detecting the reduction degree of the gas discharged from the zinc vapor discharge port 18 by the CO concentration meter 30. Then, the reducing atmosphere in the container can be controlled by injecting an inert gas from the air blowing port 19 provided in the heating container 10 or adjusting the suction of the dust collector 40. Further, since the anode 14 and the cathode 13 are carbon electrodes, it is possible to adjust the carbon monoxide concentration in the container by controlling the electrical output conditions to the electrodes. At this time, since the current affects the consumption of the carbon electrode, it is necessary to adjust the carbon monoxide concentration by controlling the current, and when the current is reduced, the output decreases and the desired temperature in the container cannot be secured. For this, it is preferable to perform automatic control so as to keep the output constant by decreasing the current and simultaneously increasing the voltage.

  On the other hand, the scrap steel plate 20 from which zinc has been removed is discharged from the opening 11 to the outside of the container, and is carried to the unloading device 60 through the unloading guide 50.

  According to the dezincing apparatus configured as described above, the scrap steel plate 20 charged in the container is heated by indirect heating by an arc while being stirred by the rotation of the heating container 10. That is, unlike the case of the induction heating method, even if the scrap steel plate 20 in the container is agitated, there is no possibility of causing a spark discharge, and the scrap steel plate 20 does not always move and stay at a certain position and is heated uniformly. Therefore, it is possible to enlarge the container in order to increase the processing amount. Similarly, since the temperature inside the container is equalized by stirring, uniform heating can be performed even if the scrap steel plate 20 has different attributes such as size, mass, and shape.

  As described above, according to the dezincing apparatus according to the present embodiment, the heating container is rotated, the scrap steel plate charged in the container is stirred, and an arc is generated on the rotating shaft of the heating container. Since the non-rotating electrode to be inserted is inserted and the scrap steel plate is heated by indirect heating with an arc, the scrap steel plate in the container can always move in the container and receive uniform heating. Moreover, since the scrap steel plate in a container moves without staying at a fixed location, it is heated uniformly irrespective of attributes, such as a magnitude | size and a shape, of a scrap steel plate. Furthermore, unlike the induction heating method, since one scrap steel plate is not always located away from the heating source, it is possible to enlarge the container in order to increase the amount of dezincing treatment. .

  As mentioned above, although the dezincing apparatus based on this invention was demonstrated based on embodiment, this invention is not limited to this, In the range which can achieve the objective of this invention and does not deviate from the summary of invention. Various design changes are possible and all are included within the scope of the present invention.

  The dezincing apparatus according to the present invention is suitable as a zinc removing apparatus for scrap steel sheets plated with zinc.

DESCRIPTION OF SYMBOLS 10 Heating container 11 Opening part 12 Arc generator 13 Cathode 14 Anode 15 Protector 16 Wear-resistant layer 17 Fire-resistant layer 18 Zinc vapor outlet 19 Blower outlet 20 Scrap steel plate 30 CO concentration meter 40 Dust collector 50 Unloading guidance part 60 Unloader

Claims (4)

A cylindrical heating container having an opening for charging a galvanized steel sheet;
Rotation driving means for rotating the entire heating container;
An arc generating means for generating an arc for heating the galvanized steel sheet by means of an electrode inserted from one end of the heating container onto the rotating shaft of the heating container. The dezincing apparatus according to claim 1, wherein the electrode is a carbon electrode. 3. The dezincing apparatus according to claim 1, wherein an electrode protection member that protects the upper part of the electrode is inserted on a rotating shaft of the heating container. The dezincification apparatus according to any one of claims 1 to 3, further comprising electrode peristalizing means that periodically and repeatedly moves the electrode on a rotation axis of the heating container.