JPH0639631B2 - Metal melting furnace - Google Patents

Description

The present invention relates to a high melting point metal (including an alloy; the same applies hereinafter) and one or more low melting point metals (including an alloy. The same applies hereinafter. .) Is the main constituent material, and the waste (including industrial waste; the same applies hereinafter) such as equipment parts and members is heat-treated to separate it into a low-melting metal melt and a high-melting metal remnant. Of the melting furnace.

In recent years, weight reduction is a major issue for automobile parts, electric parts, and the like, and therefore resins such as industrial plastics and aluminum or aluminum alloys have been used in large amounts. In addition to aluminum or aluminum alloy for weight reduction, a large amount of copper as a conductive wire is used in electric products, particularly motors. Therefore,
The need to recover expensive low-melting-point metals from such waste is increasing, and (a) a furnace with high thermal efficiency and high operating efficiency, and (b) separate collection of two or more low-melting-point metals. The emergence of possible furnaces is highly anticipated.

[Conventional technology]

Despite the long-awaited demand of the industry as described above, the present invention relates to a method and apparatus for heat-treating waste mainly composed of metal such as waste engine, and separating it into molten metal of low melting point aluminum or aluminum alloy and debris of steel material. The invention was in Japanese Examined Patent Publication Sho 56-5018.
No. 4, No. 57-4694, Jikkou No. 57-6950, No. 57-25114
As disclosed in Japanese Utility Model Publication No. 57-104296 and the like, all of them are batch type, so that not only the treatment takes a long time, but also the thermal efficiency is not good.

The invention of Japanese Examined Patent Publication No. 57-4694 is an aluminum recovery melting furnace for melting and extracting only aluminum from machine parts and automobile parts that have been recovered as waste products, and the furnace bottom is inclined to allow the molten aluminum to flow down. However, this is a so-called batch furnace in which one to several objects to be processed at one time are all replaced for each heat treatment, and the objects to be processed from room temperature to the melting temperature of aluminum for each batch processing. Since it needs to be heated up to the above and mainly uses reflected heat, there is a drawback that not only the thermal efficiency is poor, but also it takes a long time to process each object to be processed.

[Problems to be solved by the invention]

The present invention seeks to overcome such drawbacks of the prior art.

That is, since the conventionally known metal fractionation and melting and recovery furnace is a batch type, it not only has poor thermal efficiency and takes a long processing time per object, but also when there are two or more low melting point metals, It was almost impossible to separate this. The present invention intends to solve these problems all at once.

[Means for solving problems]

The present invention is an inclined furnace having two or more hearths. (A) In the lowest hearth (hereinafter referred to as the lower hearth), the object to be treated reaches its lower end due to its own weight or its inertia and movement inertia. Giving a position and inclination to slide or fall, and to one or more other hearths (hereinafter referred to as the upper hearth), the object does not slide or fall only by its own weight or its inertia and movement inertia. Along with this, a surface state and a slope are provided that are easily moved by a downward force, and (b) a molten metal receiving port at the lower part of the upper hearth for receiving a low melting point metal that melts from the object to be processed and flows down on the hearth, A molten metal reservoir is provided so that the molten metal can be taken out, for example, by allowing it to flow out when necessary. (C) The upper and lower ends of the tilting furnace are equipped with appropriate doors or doors for the objects to be processed. And (d) the upper end of the tilt furnace Outside the furnace, the processing object feeding table and the processing object on the table are sent into the furnace, and the processing objects on the upper hearth are sequentially moved downward to move the processing object at the bottom. Equipped with an extruding device for moving onto the lower hearth, sliding down or sliding down on the hearth, and discharging the (e) flame from the bottom to the top of the tilt furnace and / or combustion gas Cover your body,
Further, a burner and an exhaust gas duct are provided at positions suitable for maintaining the temperature of the molten metal, and (f) a complete combustion chamber for completely burning gas, soot, etc. exhausted from the duct is provided, if necessary. A metal melting furnace for separating and recovering a low melting point metal from an object to be treated which is substantially composed of one or more low melting point metal and a high melting point metal.

In the present invention, the low melting point metal, a metal having a melting point of 1100 ° C. or lower, that is, tin, lead, zinc, magnesium, aluminum, barium, strontium, germanium, silver,
Gold, copper and the like means alloys based on these and the like, and the high melting point metal, a metal having a melting point of 1400 ° C. or higher, that is, silicon, nickel, cobalt, iron, titanium, platinum, zirconium, chromium, Indium, niobium, tantalum, tungsten and the like and alloys based on them have a melting point of 1400 ° C. or higher.

Further, in the present invention, "a surface state that easily moves by a downward force along the hearth" or "... form so as to easily move" means that a normal cold or hot rolling is performed. It means a surface condition almost equal to that of the manufactured iron plate or steel plate, or a surface condition in which a suitable groove is bored in the surface in a direction that does not hinder the movement of the object to be treated, if necessary. In the present invention, the inclined furnace is a cylindrical furnace installed at a constant inclination angle with respect to the horizontal plane, and the heating method is heating by combustion heat of oil or gas mainly used as fuel.

The constant inclination angle of the inclined furnace is for flowing down the low melting point metal to be melted and separated in a certain direction in order to collect it in the basin, but at the same time, the work to be processed in the furnace has a small amount of work. To provide a means for making it extremely easy to carry out the operation of feeding (energy), moving or stopping it in the furnace, and discharging it to the outside of the furnace after the completion of the treatment (dissolution and separation of low melting point metal). It is a thing.

The inclination angle required for each furnace bottom differs depending on the shape, weight, position of the center of gravity, rough surface sliding condition, etc. of the object to be processed and the rough sliding condition of the furnace bottom. For the body there is an optimum constant tilt angle (especially for the upper hearth).

Therefore, in order to process various objects having different specifications or specifications under optimum conditions, a structure in which the tilt of the tilt furnace is variable is required.

However, it is possible to provide a moving part in a large furnace and change the inclination of the moving part (particularly for the part corresponding to the upper hearth), but it is not possible to actually change the inclination of the furnace. Since it requires as much work as repair work of the furnace that requires attachment and detachment, it is not so easy to generalize the furnace by changing the inclination.

If the energy required to move the object on the upper hearth is allowed to be sacrificed to some extent, the inclination of the upper hearth is set to a certain angle (for example, 10 °) or less, so that Can be generalized.

Also, in the lower hearth, a certain angle (eg 40 °)
By the above, the general purpose of the general use is achieved.

As the furnace length of the gradient furnace of the present invention, in consideration of its efficiency and action, a pre-tropical zone, a heating zone and a soaking zone are provided for each of one or more low melting point metals contained in the object to be treated. In addition, it is necessary to have a sufficient length to form a release zone for releasing the debris after the low melting point metal is eluted to the outside of the furnace.

In the furnace of the present invention, the object to be treated is composed of a metal having a high melting point and a metal having a low melting point, and may be covered with a resin or a fat or oil. The form and the position thereof in the furnace are not particularly limited as long as the melted low melting point metal completely flows out.

As the main burner, an oil-burning type burner with a large calorific value is suitable, and its installation location is most suitable for heating the object to be processed, and it is also necessary to keep the molten metal heat-retaining. , Below the soaking zone or above the lower hearth.

The heat retention of the molten metal held in the molten metal pool can be performed by appropriately inducing the combustion gas of the main burner (the opening to the flue is appropriately provided), but an auxiliary burner for heat retention is used. It does not impede the provision at an appropriate position in the pool. The gas burner is more suitable than the oil combustion type as the auxiliary burner.

Further, as the oil, in addition to ordinary combustion oil, pyrolysis oil of waste tires is preferably used, and as the fuel gas, pyrolysis gas of waste tires is very preferably used.

The doors or doors installed at the upper end of the upper hearth and the lower end of the lower hearth for receiving or releasing the object to be treated may be appropriately selected from sliding doors, hinged doors, open / close doors, etc. An automatic device such as an interlocking device with the, a time difference opening / closing device for the upper and lower doors, and an interlocking device with the timer of the pushing device can be attached.

An ordinary hydraulic pusher is appropriately used as the extrusion device, but as the allowable range of extrusion pressure, strength, etc., it is necessary to design and manufacture with sufficient margin and install it It is important to raise. As a modification of the extrusion device, a belt type, bucket type or gripping type conveyor having a large friction resistance can be considered.

Next, embodiments of the present invention will be described with reference to the drawings, but the present invention is not limited thereto.

[Example 1] In Fig. 1, reference numeral 1 denotes a tilted furnace main body, which has an outer wall for holding the outer shape of the furnace, a framework (not shown), and the like,
The inner ceiling portion 1'and the side wall portion are covered with refractory bricks. 2 is an upper hearth, and 3 is a lower hearth, and a smooth steel plate is preferably used as a floor plate for both, but in the portion near the side wall of the hearth, the object 4 does not collide with the side wall, or In order to advance the center part of the hearth downward along the hearth without damaging the side wall, the upper part is rounded, raised, or lined with a steel plate in whole or in part (at a predetermined height or (With a width) is preferred. The back side of the hearth is covered with refractory insulation. The inclination of the hearth is such that, in the upper hearth 2, all of the objects to be treated 4 do not slide or fall by their own weight or only inertia of the own weight and movement, but they move smoothly due to the downward force along the hearth. And That is, in the extending direction of the upper hearth to the outside of the hearth, the object transfer table 6 is provided (in one case with the hearth),
An object to be processed 4-1 is prepared in advance in a state of waiting for delivery. The object to be treated is a door or sliding door 5 at the upper end of the hearth.
It is fed into the furnace by opening the pusher plate 8 of the pusher 7 and advancing the pushing plate 8. The feed pressure is sequentially transmitted downward and the row of objects to be processed is moved downward, and the lowest melting point The object to be treated 4-Y from which the metal elution has been completed is slid down from the lower end of the upper hearth to reach the lower hearth 3 and falls or slides down on the lower hearth. At this time, when the inclination of the upper hearth is appropriate, the row of objects to be processed arranged from the upper side to the lower side along the hearth moves smoothly by the force of the relatively small pusher. For example, in the case of an abandoned engine of an automobile, the steel plate angle at the time of starting to fall or slide on the smooth steel plate due to its own weight is about 35 ° with respect to the horizontal plane, and therefore the upper hearth of the present invention in this case is preferable. The inclination is usually 30 ° to less than 35 ° with respect to the horizontal plane, and the most preferable inclination angle is often about 32 °. Aligning the objects to be processed on the upper hearth adjusted to the most preferable inclination angle, the row of the objects to be processed moves smoothly downward when pushed lightly with the pusher, and only the object at the bottom end slides or falls, When the pushers are made to stand still at the time of the drop, the rows of the objects to be processed are also stopped at substantially the same time. Lower hearth 3
Slides or falls from the lower end of the upper hearth 2 (slave metal of low melting point is almost completely eluted) to the door or sliding door 9 at the lower end of the furnace, and opens and closes the sliding door or sliding door 9. By doing so, it plays the role of releasing it to the outside, and the angle is 35 ° or more, preferably 45 in the case of an abandoned engine.
It is about -60 °.

The steel plate for the upper hearth may be mild steel, but casting steel having a relatively high carbon content is preferably used. The surface of the steel sheet is preferably smooth, and guide rails, grooves for guiding the molten metal, etc. may interfere with smooth movement of the object to be treated, and are not necessarily preferable. In the lower part of the upper hearth, a basin that flows down on the upper hearth and receives the low melting point metal 10 that drops or flows from the lower end.
11 is provided, and an auxiliary burner 12 for heat retention can be provided if necessary, and a molten metal outlet 13 is provided at the bottom of the hot water reservoir 11.

An overflow port (not shown) can be provided near the surface of the bath, but it is difficult to operate due to the difficulty of heat retention.

A down arch 14 and a down arm 15 for guiding flames and preventing the invasion of outside air can be provided at the upper part of the tilt furnace.

The main burner 16 is located in the upper space of the lower hearth and is usually operated only by the main burner. The flame of the burner having a temperature of 1200 ° C to 1300 ° C or higher rises mainly while heating the inside of the object to be treated and the gradient furnace, and becomes a hot airflow of 600 ° C or more and enters the flue 18 through the flue inlet 17.

Depending on the situation in which the object to be processed is heat-treated, it can be referred to as a soaking and melting zone, a heating zone and a pre-tropical zone in order from the bottom inside the gradient furnace. The pre-tropical zone has an effect of effectively utilizing the heat quantity of the hot air stream which flows into the flue due to the heat received by the object to be treated at room temperature sent into the furnace, and has the effect of lowering the temperature as much as possible. Next, the preheated object is heated sequentially while moving downward in the heating zone until reaching the melting point of the low melting point metal or higher. The melting of the low melting point metal is continued until the elution is completely completed in the next soaking zone.

Even when the auxiliary burner is not used, it is possible to secure the heat retention of the molten metal by guiding a part of the flame of the main burner 16 through the upper space of the hot water reservoir 11 to the flue 18.

There is a damper 19 in the flue so that the amount of exhaust gas as well as the flame of the burner and the amount of supplied air can be adjusted. A portion of the flue 18 can also be manipulated to form a combustion zone that completely combusts incompletely combusted gases such as oil, plastics, etc. generated in the pre-tropics. Waste gas from the flue is emitted into the atmosphere through the scrubbing tower or as is from the chimney.

On the other hand, the remains of the iron ingot released from the lower end of the furnace are transported and deposited at a deposition site (not shown) by an appropriate transportation means.

The inclination of the upper hearth of the metal melting furnace shown in FIG. 1 is about 30 to 32 °, and the inclination of the lower hearth is about 50 to 52 °.
This angle is an angle suitable for achieving the object of the present invention when an engine of about 220 kg is used as the object to be processed, and from the angle of about 25 ° in the case of the upper hearth depending on the shape and external friction. It varies up to about 35 ° (of course, 20 ° or 15 ° or less can be used by increasing the power of the pusher, but it is not preferable). In this case, while keeping the furnace temperature constant for each of the zones,
The object to be processed can be continuously fed and discharged, usually 2
Every ~ 3 minutes, in the most efficient operation, one object can be processed every 1.7 minutes. In this case, the number of objects to be treated held in the furnace was 20, and the retention time in the furnace was 34 minutes on average. Further, the amount of the object to be treated, which was treated by continuous operation for 8 hours, was about 55 tons, and the amount of the molten aluminum obtained by separation was about 5 tons. This efficiency requires 40 to 60 minutes for one cycle (8 to 12 cycles in 8 hours, the amount to be processed of the object is about 2 to 2.5 tons) in the case of a batch method such as Japanese Patent Publication No. 56-50184. In comparison, it is a significant improvement in efficiency.

In addition, the pusher also has a cylinder diameter of approximately 150 mm and is 20 kg / c.
A hydraulic cylinder type of about m ² is used well. The furnace length is determined by the processing speed and the retention time of the object to be processed,
When iron and aluminum are separated, the results of this example are sufficiently informative values.

Dry fuel gas or oil of a waste rubber tire was preferably used as the fuel oil or gas, and the calorific value of the total fuel consumed in the continuous operation for 8 hours was 15 × 10 ⁶ kcal.

[Embodiment 2] FIG. 2 shows a metal melting furnace for separately melting and separating a target object containing two kinds of low melting point metals (aluminum and copper) like a motor.

In FIG. 2, reference numeral 1 denotes a tilted furnace main body, which has an outer wall for holding the outer shape of the furnace body, a framework (not shown), etc., and an inner ceiling 1'and side walls covered with refractory bricks. It is being appreciated. 2-A is an upper hearth in the upper stage, 2-B is an upper hearth in the lower stage, and 3 is a lower hearth. In each case, a smooth steel plate is preferably used as the floor plate, but in the portion close to the side wall of the hearth, the object to be processed 4 advances downward along the hearth without colliding with the side wall or damaging the side wall. It is preferable to round, bulge, or attach steel sheet lining to all or part of the sidewall (at a predetermined height or width). The back side of the hearth is covered with refractory insulation.

In the upper hearths 2-A and 2-B, the inclination of the hearth is
All of the objects to be processed 4 do not slide or fall by their own weight or only inertia of their own weight and movement, but they are to be smoothly moved by a downward force along the hearth. For example, in the direction of extension of the upper hearth 2-A to the outside of the furnace, the processing object feeding table 6
(In some cases integrated with the upper hearth), the objects 4-1 and 4-2 to be processed are prepared for the next feeding. The object to be treated is fed into the furnace by opening the door or sliding door 5 at the upper end of the upper hearth 2-A and advancing the extrusion palm portion 8 of the pusher 7, but the feeding pressure is gradually lowered. While transferring the object to be processed and moving the row of the objects to be processed downward, the objects to be processed 4-Y-1 and 4-Y-2 in which the low melting metal or alloy at the bottom of the lower upper hearth is eluted Lower hearth 3 by sliding it from the lower end of the upper hearth 2-B
Allow it to reach the top and slide or fall on the lower hearth. At that time, when the inclination of the upper hearth is appropriate, the objects to be processed which are lined up from the upper part along the hearth move smoothly in each order by a relatively small pusher force. . For example, in the case of a motor, the angle of the steel plate when it starts rolling or sliding on a smooth steel plate is about 12 to 15 ° with respect to the horizontal plane.
The preferable inclination of the upper hearth in the present invention is usually 10 to 12 ° with respect to the horizontal plane, and it is most preferable to install it at about 11 °. In such a case, pressing lightly with the pusher causes the object to be processed to smoothly move downward in the same order, and is located at the bottom end of the lower upper hearth 2-B (the number corresponding to the number sent). Only the object to be processed slides or falls, but when the pusher is stopped during the fall, the row of objects to be processed also stops at the same time.

The lower hearth 3 slides or falls from the lower end of the lower upper hearth 2-A (irons that have almost completely eluted the two low melting metals) to the door or sliding door 9 at the lower end of the furnace. It plays a role of discharging to the outside by sliding or falling and opening and closing the door or sliding door in conjunction with the operation of the pusher or the sliding of debris.The angle of the waste motor is 15 ° or more, preferably 25 ° or more. It is about 60 °.

Steel for casting is preferably used as the steel sheet for the upper hearth, and the surface thereof is preferably smooth. Metals 10-A (aluminum in this case) and 10-B (copper in this case) with a low melting point that flow down on the upper hearth to the lower parts of the upper hearths 2-A and 2-B, and drop or flow down from the lower end , 11-B and 11-B, respectively, which can be provided with auxiliary burners 12-A and 12-B for heat retention if necessary, and 11-A and 11-B The molten metal outlets 13-A and 13-B are provided in the lower part of the.

Down arches 14-1 and 14-2 and a down arm 15 for guiding flames and preventing invasion of outside air can be provided in the upper part of the gradient furnace.

The main burner 16-A is located in the upper space at the top of the lower upper hearth, and the main burner 16-B is located in the upper space of the lower hearth, and is usually operated only by these main burners. . In the furnace corresponding to the upper hearth of the upper stage, pre-heat zone, heating zone,
The soaking zone is formed and the aluminum is melt-separated, and this part is the preheating zone for the heating zone and the soaking zone for the copper melt separation performed in the furnace corresponding to the lower upper hearth. It also has a role. The temperature of the melting and soaking zone in the furnace is aluminum (melting point 660 ° C) and copper (melting point 1), respectively.
Since it is necessary to maintain a high temperature to efficiently melt (0.83 ° C.), the outside of the door or the sliding door 9 is, for example, for airtightly receiving the debris from which the metal having a low melting point is eluted in order to keep the airtightness when opening and closing the door or the sliding door 9. It is necessary to provide an airtight chamber (not shown) to prevent heat loss and to maintain the temperature of the lower end of the lower upper hearth 2-B and maintain the thermal efficiency of the entire furnace as compared with the case of the furnace of FIG. Will also be significantly higher. Although the heat loss is a little larger than that of the airtight chamber, it is not an extrusion plate at the tip of the pusher 7, but an extrusion palm such as 8 in FIG. The heat loss at the time of feeding the object to be processed can be reduced by using the structure of the extruding part that minimizes the gap for hitting the door and sucking the atmosphere.

Although most of the operation is performed by the main burners 16-A and 16-B, the auxiliary burner 12-B is used more frequently than 12-A to maintain its hot water temperature because of the high melting point of copper.

In order to operate this furnace smoothly, the main burner 16-A and
Not only regulates combustion (energy) of 16-B, but also keeps dampers 19-A, 19-B (not shown, lateral feed-in damper corresponding to flue 18-B) and 19-C properly It is necessary and requires considerable experience and skill to carry out the operation properly.

The gas or smoke generated by incomplete combustion of oil, plastic, etc. in the pretropical zone above the upper hearth of the upper stage
It is easy to carry out an operation such that complete combustion is performed in A. Waste gas from the flue 18-C is discharged into the atmosphere either through the scrubbing tower or as is from the chimney.

On the other hand, the remains of the iron ingot released from the lower end of the furnace are transported to a deposition site (not shown) by an appropriate transportation means (not shown).
Is deposited.

The inclination of the upper hearth of the metal melting furnace shown in FIG. 2 is about 11 to 12 °, and the inclination of the lower hearth is about 48 to 50 °, but this angle covers a motor of about 2 kg. In the case of the treated body, it is an angle suitable for achieving the object of the present invention, and in the case of the upper hearth depending on the state and the state of external friction, it is about 10 to about 10.
Change up to 15 ° (Of course, it is possible to operate at 8 ° or 5 ° or less, but this is not preferable, and there is a lot of wasted power, and turbulence in the transfer of objects in the furnace such as row disturbance due to increased friction. May occur.).

The temperature inside the furnace is 600 to 650 ℃, 650 to 750 ℃ in the pre-tropical zone above the upper hearth, the heating zone, and the soaking and melting zone, respectively.
750 to 900 ° C, and 900 to 1300 ° C and 1300 to 1400 ° C in the heating zone and the soaking and melting zone on the lower upper hearth.

A bar such as a round bar made of steel suitable for smoothly transferring the object to be processed from the upper hearth of the upper stage to the upper hearth of the lower stage 20
Can be installed laterally, but is not essential depending on the structure.

In the case of the present embodiment, the feeding and discharging are normally performed every 3 to 5 minutes, and at the time of the best efficiency operation, 42 objects to be treated can be treated per minute. In this case, the number of objects to be treated held in the furnace was 2500, and the staying time in the furnace was 60 minutes on average. Further, the object to be treated after continuous operation for 8 hours was about 100 tons, the molten aluminum obtained by separation was about 1600 kg, and the molten copper was 6.4 tons. The furnace of the present invention is a melting furnace that continuously separates and collects two or more low melting point metals from scrap as in the present embodiment, and is not only a novel one by itself, but also its processing capacity is extremely high. . Further, according to the present invention required for the above-mentioned continuous treatment for 8 hours, the low melting point metal is fractionally recovered from the object to be treated which is substantially composed of one or more low melting point metal and high melting point metal. Although it is a melting furnace for metals, the low melting point metals include not only aluminum and copper but also metals or alloys such as tin, lead, zinc, silver and gold.

The high-melting metal or alloy corresponds to a metal or alloy such as iron, titanium, zirconium.

〔effect〕

As shown in Examples 1 and 2, the metal melting furnace of the present invention is of a continuous type and has a very high processing capacity and very low fuel consumption. (The continuous melting furnace capable of separately melting and recovering two or more kinds of low melting point metals as in the present invention is
It's completely new and I don't see any other examples. )

[Brief description of drawings]

FIG. 1 and FIG. 2 are vertical cross-sectional views showing the structure of the essential part of the melting furnace of the present invention and the operating state thereof when the melting point of the low melting point metal is one and two, respectively. is there. In Fig. 1 and Fig. 2, 1 ... inclined furnace body, 2 ... upper hearth, 2-A ... upper upper hearth, 2-B ... lower upper hearth, 3 ... lower furnace Floor, 4 ... Object to be treated, 5 ... Door or sliding door at upper end of hearth, 6 ... Injecting base for object, 7 ... Pusher 9 ... Door or sliding door at lower end of furnace, 11, 11 -A, 11-B …… hot water pool, 12, 12-A, 12-B …… auxiliary burner 13, 13-A, 13-B …… molten metal outlet 14, 14-1, 14-2 …… furnace Ceiling down arch 15 …… Down arm 16, 16-A, 16-B …… Main burner 17, 17-A, 17-B …… Flue entrance 18, 18-A, 18-B, 18-C… … Flue 19, 19-A, 19-C …… Damper 20 …… Bar

Claims (1)

[Claims] 1. In a cylindrical tilt furnace having two or more tilt hearths, (a) the lowest hearth (hereinafter referred to as the lower hearth) has its own weight or an inertia of movement with its own weight. Gives a position and inclination to slide down or fall to the bottom of the hearth, and the other one or more hearths (referred to as the upper hearth) does not slide down or fall only on its own weight or its own weight and inertia of movement, It gives a surface state and inclination that moves easily by the downward force along the hearth, and (b) accepts a low melting point metal or alloy that melts from the object to be processed and flows down on the bottom of the upper hearth. Provided with a molten metal receiving port and a molten metal reservoir capable of storing the molten metal and taking out the molten metal as needed, (c) the upper end and the lower end of the inclining furnace are each provided with an appropriate door or door. Forming the inlet and outlet of the processing body, Outside the furnace at the upper end, the processing object feeding table and the processing object on the table are sent into the furnace, and the processing object on the upper hearth is sequentially moved downward, and the processing object at the bottom is processed. A body is moved onto the lower hearth, and an extrusion device for sliding down or falling on the hearth and discharging is provided, and (e) on the upper hearth by the flame flow and / or combustion gas from the lower part to the upper part of the tilt furnace. A burner and an exhaust gas duct suitable for covering the object to be treated and maintaining the temperature of the molten metal, a main burner in the upper space of the lower hearth, and an auxiliary burner for heat retention as necessary, (F) The gas discharged from the duct, a complete combustion chamber that completely burns soot, etc. is provided, and one or more kinds of low melting point metal or alloy and high melting point metal or alloy are substantially used. From the object to be processed, the low melting point metal or Metal melting furnace to sort and collect gold.