JPS6056989B2 - metal melting furnace - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a metal melting furnace for melting metals such as aluminum, iron, etc., particularly recovered metal waste, for recycling.

Conventional melting furnaces for melting aluminum waste include one in which the aluminum waste is placed in an iron kettle and the iron kettle is heated to melt the aluminum waste therein, and one in which the aluminum waste is placed in the furnace and a burner In some cases, combustion gas from aluminum is directly blown onto aluminum waste to dissolve it.

However, in the former case, the iron content liberated from the iron kettle contaminates the recycled aluminum and reduces its purity, while in the latter case, it is not possible to dissolve a large amount of aluminum waste at the same time. In addition, the recycled aluminum was forcibly oxidized by the combustion gas, producing a large amount of oxides. The present invention has been made to eliminate these drawbacks, and involves placing metal waste in a melting tank made of non-metallic refractories such as castable refractories, and indirectly discharging the metal waste through this melting tank. It is designed to be heated.

In addition, such a melting tank is installed in a heat storage type insulation chamber, and a heating space is formed between the bottom wall of the melting tank and the inner bottom surface of the heat insulating layer, and a vertical flame path is formed on the side wall of the melting tank to burn the fuel. By guiding the combustion gas generated indoors to the heating space and from there to the flame duct, the metal waste in the melting tank can be heated and melted with high thermal efficiency. moreover,
A preheating space for accommodating the material to be melted (metal waste) is formed in the heat insulating chamber above the melting tank in order to effectively utilize heat and shorten the melting time. An embodiment of the present invention will be described in detail below based on the drawings.

This metal melting furnace includes a melting tank 2 with an open top inside a heat storage type heat insulation chamber 1, and a fuel combustion chamber 3 outside the heat storage type heat insulation chamber 1.

The heat storage type insulation room 1 has a heat insulation layer 5 made of a heat insulating material such as asbestos or ceramic on the inside of an exterior 4 made of reinforced concrete.
In addition, an interior 6 made of brick and having a heat storage effect is formed inside it. In the center of the upper wall of the heat insulating chamber 1, an input port 7 is formed into which metal waste to be melted, such as aluminum waste M, is input. This inlet 7 is opened and closed by two outer cover plates 8, front and rear. These outer cover plates 8 are fitted onto a pair of rails 9 laid on the upper surface of the upper wall of the heat insulating chamber 1 so as to be slidable back and forth, and are opened and closed by air cylinders or hydraulic cylinders 10, respectively. As shown in FIGS. 1 and 4, two left and right inner cover plates 11 are pivotally mounted on the lower side of the inlet 7 so as to be movable up and down.

When these inner cover plates 11 are closed, aluminum waste M
The space between these and the outer cover plate 8 serves as a preheating space 12 for accommodating and preheating the aluminum waste M. The inner cover plate 11 can be opened and closed from the outside of the heat insulation chamber 1 by means of a rotating shaft 13 extending through the heat insulation chamber 1 . The aluminum waste M in the preheating space 12 is thrown in by opening the inner cover plate 11 when the molten metal M'' in the melting tank 2 is taken out to the outside and becomes half, for example. Since the outer cover plate 8 can be closed, hot air will not escape.The melting tank 2 is made of castable refractory material (
For example, it is made of a mixture of alumina or cyanite aggregate and hydraulic cement), and is molded on a heat-resistant stainless steel plate 14 installed almost horizontally within the interior space of the heat insulating chamber 1. The space between the stainless steel plate 14 and the inner bottom surface 15 of the heat insulating chamber 1 (the inner bottom surface of the interior 6) is a heating space 16 for heating the melting tank 2 from below. This heating space 16 is communicated with the fuel combustion chamber 3 via a combustion gas inlet passage 17 at its rear end. Both the left and right side walls 18 and the front side wall 19 of the dissolution tank 2 are the insulation chamber 1.
While the rear wall 20 is in contact with the interior 6 of the rear wall 20, the rear wall 20 is separated from the interior 6 and forms an exhaust space 21 therebetween.

This exhaust space 21 communicates with the atmosphere via a flue 22. A plurality of vertically elongated flame paths 23 are provided on the left and right side walls 18 and the front side wall 19 of the dissolution tank 2, respectively. Each flame path 23 is formed by embedding a stainless steel rectangular tube 24 in the side walls 18 and 19, and the upper end of each rectangular tube 24 projects upward from the upper end of the melting tank 2. A pair of hoppers 26 are connected to the fuel combustion chamber 3 via a screw feeder 25, and the solid fuel fed into the hopper 26 is fed into the fuel combustion chamber 3 by the screw feeder 25. . As a solid fuel, waste paper pressed and cut into cubes several d in size is preferred because it is lightweight, convenient to handle, and can be obtained at low cost, but coal,
Ogarite etc. may also be used. As shown in FIG. 5, a valve plate 27 is pivotally mounted at the outlet of the screw feeder 25 so as to close under its own weight. When the screw conveyor 28 rotates, the solid fuel pushes the valve plate 27 open and flows into the fuel combustion chamber. Enter within 3.

Since the screw conveyor 28 does not span the entire length inside the screw feeder 25 and is interrupted in the middle, a portion of the solid fuel is distributed between the tip of the screw conveyor 28 and the valve plate 2.
The fuel is stored in a space " between the fuel combustion chamber 3 and the fuel combustion chamber 3, and acts as an insulator against the heat from the fuel combustion chamber 3.Furthermore, the screw feeder 25 is cooled by a water-cooled vibe 29 surrounding its outer peripheral surface. In the combustion chamber 3, a nozzle 30 is installed substantially horizontally, and a plurality of air supply pipes 31 having a large number of air holes are arranged substantially vertically.

These nozzles 30 and air supply pipes 31 are connected to blowers 32 and 33 on the outside of the fuel combustion chamber 3, respectively, and dampers 34 and 35 are installed inside each of them. In order to ignite the solid fuel in the fuel combustion chamber 3, the exhaust valve 36 (FIG. 5) is opened and the exhaust fan 38 is operated to ignite the solid fuel through the ignition window 39.

Ash produced by combustion is discharged by rotating an impeller 40 attached to the lower end opening of the fuel combustion chamber 3 and collected in an ash collector 41. The high-temperature combustion gas in the fuel combustion chamber 3 is sent into the combustion gas inlet passage 17 by air injected through the nozzle 30 and is completely combusted, and then is sent into the heating space 16 to heat the melting tank 2. It heats from below, ascends through the flame duct 23 and heats the melting tank 2 from both left and right sides and from the front, and then enters the space 42 above and directly heats the aluminum waste inside the melting tank 2. At the same time, after the aluminum waste M in the preheating space 12 is preheated, it is discharged into the atmosphere through the exhaust space 21 and the flue 22.

Therefore, the aluminum waste in the melting tank 2 is thermally efficiently and uniformly heated and melted. The molten aluminum M' is taken out to a required vessel outside the heat insulating chamber 1 through the outflow path 43 (FIG. 2). The inner bottom surface of the dissolution tank 2 is inclined downward toward the inlet side of the outflow path 43. Although a slight oxide film may be formed on the upper surface of the molten aluminum M'', the oxide film is scraped out by opening the lid 45 of the extraction passage 44 and using an appropriate scraping tool. In the above, the fuel combustion chamber 3 is provided separately outside the heat insulation chamber 1, but it may also be provided inside the heat insulation chamber 1 and at the center of the lower side of the heating space 16.

Furthermore, the melting tank 2 may be made of a non-metallic refractory other than castable refractories. As described above, the present invention has the following effects. 1. Metal waste is placed in a melting tank made of non-metallic refractories such as castable refractories, and the metal waste is indirectly heated and melted through this melting tank.
High purity recycled metal can be obtained.

2. A melting tank is installed in a heat storage type heat insulation chamber, and a heating space is formed between the bottom wall of the melting tank and the inner bottom surface of the heat insulation chamber, and a vertical flame path is formed on the side wall of the melting tank. The generated combustion gas is guided into the heating space to heat the melting tank from below, and is also raised through the flame duct to heat the melting tank from inside its side walls, making it possible to efficiently heat the metal waste inside the melting tank. And it can be heated and dissolved uniformly.

3. Since a preheating space is formed in the heat storage type heat insulating chamber and above the melting tank, the metal waste can be preheated before being put into the melting tank, making effective use of heat and shortening the melting time.

[Brief explanation of drawings]

The drawings show an embodiment of the invention, with FIG. 1 being a vertical sectional view;
2 is a horizontal sectional view, FIG. 3 is a plan view, FIG. 4 is a sectional view of the metal waste input section, and FIG. 5 is a sectional view of the fuel supply and combustion section. DESCRIPTION OF SYMBOLS 1... Heat insulation chamber, 2... Melting tank, 16... Heating space, 23... Flame duct, 3... Fuel combustion chamber, 12... Preheating space.

Claims (1)

[Claims] 1 A melting tank made of a non-metallic refractory such as a castable refractory is provided in the heat storage type insulation chamber, and a heating space is formed between the bottom wall of the melting tank and the inner bottom surface of the heat insulation chamber, and the side wall of the melting tank is A vertically elongated disaster path communicating with the heating space is formed, and the heating space is communicated with the fuel combustion chamber, and a preheating space for accommodating undissolved materials is provided in the heat insulation chamber and above the melting tank. A metal melting furnace characterized by forming.