WO2017051586A1

WO2017051586A1 - Aluminum chip melting apparatus and melting method

Info

Publication number: WO2017051586A1
Application number: PCT/JP2016/069969
Authority: WO
Inventors: 秀昭楢原; 俊治岩崎; 洋二青木; 峻輔蒔田
Original assignee: 株式会社広築
Priority date: 2015-09-26
Filing date: 2016-07-06
Publication date: 2017-03-30
Also published as: JPWO2017051586A1; JP6452182B2

Abstract

The present invention provides an aluminum chip melting apparatus that melts chips, which are aluminum metal or alloy cuttings, to obtain molten aluminum. This aluminum chip melting apparatus is characterized by being provided with: a centrifugal oil-water separating apparatus that reduces oily water in the cutting oil adhering to aluminum chips; a drying/preheating means for eliminating water in the cutting oil adhering to the aluminum chips; a charging means for charging the dried/preheated aluminum chips into the molten metal in a crucible melting furnace; an aluminum melting means for melting the dried/preheated aluminum chips using the crucible melting furnace, and producing molten aluminum; and an oil gasification combustion means for gasifying the oil remaining in the dried/preheated aluminum chips using the crucible melting furnace, and burning the result with a combustion burner.

Description

Aluminum chip melting apparatus and melting method

The present invention relates to an aluminum chip melting apparatus and a melting method, and in particular, in obtaining a molten aluminum by melting chips that are cutting scraps of aluminum metal or alloy, pay attention to environmental protection, and provide safe and energy-saving operation. The present invention relates to an aluminum chip melting apparatus and a melting method that can be achieved.

Aluminum metal requires a large amount of power for its production, so its production cost is high. Therefore, as long as scrap and scrap generated when processing into an aluminum product take the form of aluminum metal, the value is great in consideration of the manufacturing cost. Therefore, it is usual to recycle and melt aluminum scraps, cans and the like to obtain molten aluminum, and then to make aluminum products, and aluminum metal cutting scraps, so-called aluminum chips, are similarly treated.

It is desirable from the viewpoint of resource saving and energy saving that aluminum chips are remelted and recycled as aluminum. For this reason, it is desirable from the viewpoint of environmental conservation such as the quality of the molten aluminum and the prevention of smoke generation during production that the cutting oil adhering to the chips is removed by heating and evaporation before the chips are dissolved. As an example, as shown in the flow chart of FIG. 12, aluminum chips after remaining cutting oil and the like are calcined in a rotary kiln so that the aluminum is not oxidized and removed by volatilizing oil and moisture, and then aluminum. There is one that obtains molten aluminum by charging chips into an aluminum melting furnace. The volatilized oil is burned in a reburning furnace and diffused to the atmosphere through a dust collector. This equipment is good in that aluminum chips can be reused, but the equipment requires a large variety of equipment, etc., and when it is dried and calcined, it is used in dust collectors and ducts with aluminum dust generated from the rotary kiln. There were problems such as the risk of ignition and explosion.

In addition to the above, return materials, cans, and briquettes containing chips such as aluminum are indirectly heated in the preheating tower using the combustion exhaust gas from the melting and holding furnace to burn off the oil, etc. Prior art for charging to obtain molten metal is disclosed.

Japanese Patent Laying-Open No. 2005-121289 ([0006-0007], [0013], [FIG. 1])

The above prior art is excellent in that it is preheated so as not to oxidize the return material and briquette material containing chips by indirect heating, but the oil adhering to the material to be melted such as chips is heated and evaporated in the inner case. After that, it is said that it is possible to effectively suppress flue gas generation because it can be removed by entrapping and burning new air at the upper end of the preheating tower, but it is difficult to completely prevent flue gas generation, and oil etc. are retained There were problems such as not using latent heat energy.

The present invention solves these problems, leaving only the oil by pretreatment of the aluminum chips accompanying the cutting oil, and then melting it in an aluminum melting furnace to obtain a high-quality molten aluminum, An object of the present invention is to provide an aluminum chip melting apparatus and a melting method capable of saving energy and preventing air pollution by substituting fuel for gasification of oil in a melting furnace, inviting it to a heating burner of the melting furnace, and burning it. It is what.

In order to achieve the above object, an aluminum chip melting apparatus according to claim 1 of the present invention comprises a drying / preheating means for removing moisture in the cutting oil adhered to the aluminum chip, and the dried / preheated aluminum chip. Aluminum for producing molten aluminum by melting the dry and preheated aluminum chips using charging means for charging the powder into the molten metal of the crucible melting furnace and the crucible melting furnace indirectly heated by a combustion burner Melting means, and when the aluminum chips are melted in the crucible melting furnace, the oil remaining in the dried and preheated aluminum chips is gasified and attracted to the combustion burner to be burned. An oil gasification combustion means is provided.

As the cutting oil used for producing aluminum products by cutting aluminum, an emulsion obtained by diluting water-soluble cutting oil with water is often used. Therefore, since the aluminum chips that are cutting scraps are accompanied by 10 to 20 wt% of cutting oil with respect to the oil-containing chips, a mixture of oil and water is attached. The breakdown is 5 to 15 wt% of oil and 1 to 5 wt% of water. By adopting the structure of the first aspect, moisture is removed by heating and evaporation from the cutting oil accompanying the aluminum swarf, and only the oil is left and then charged into a melting furnace to obtain a molten aluminum. At the same time, the oil can be gasified and combusted as a partial substitute fuel for the heating burner of the melting furnace. As a result, it is possible to recover aluminum as a fuel for the melting furnace without recovering resources from the aluminum chips and gasifying the accompanying cutting oil to cause pollution such as air pollution.

In addition, the aluminum chip melting apparatus according to claim 2 is the aluminum chip melting apparatus according to claim 1, wherein the drying / preheating means conveys the aluminum chip by a drying / preheating screw conveyor in which the aluminum chips are sealed, The aluminum chips are dried and preheated by heating the outer peripheral wall of the screw conveyor while adjusting the temperature of the combustion exhaust gas from the crucible melting furnace.

With this configuration, when the outer periphery of the drying / preheating screw conveyor is heated with the melting furnace combustion exhaust gas at a predetermined temperature, the transported aluminum chips inside the screw conveyor evaporate the water in the accompanying cutting oil, while the oil component evaporates. In the state which is not carried out, the aluminum chip is preheated and can be sent to the charging apparatus of the next process.

Further, an aluminum chip melting apparatus according to claim 3 is the aluminum chip melting apparatus according to

claim

1 or 2, wherein the crucible melting furnace is provided with a refractory partition wall in the depth direction of the molten metal pool. The molten metal part is divided into a molten part and a molten part, and further provided with a refractory filter over the entire horizontal cross section below the molten surface of the molten part, and the dried and preheated aluminum chips are It is charged into the molten metal at the lower part of the filter by charging means, and the aluminum chips are melted, and the oil component derived from the cutting oil accompanying the aluminum chips is gasified and the oil gas is taken out from the upper surface of the melting part. The combustion burner is used for combustion.

With this configuration, the aluminum chips accompanying the oil are forcibly inserted into the lower part of the filter of the melting part, and the upward movement of the aluminum chips is suppressed by the filter. Then, the molten aluminum passes under the partition wall and moves to the molten metal part, and finally is discharged from the tapping tank. The partition wall prevents the molten metal from short-circuiting and takes a long residence time. Thus, the slag component, which is an impurity, can be floated and separated, and the molten metal is sufficiently cleaned. The oil is easily gasified because the oil-containing chips are sufficiently heated under the filter, floats through the filter, moves to the space above the melt, and then has a venturi effect on the combustion burner. Attracted and burned to replace the fuel, contributing to energy savings as well as saving fuel from melting aluminum.

An aluminum chip melting apparatus according to claim 4 is the aluminum chip melting apparatus according to claim 3, wherein the melting part of the crucible melting furnace removes the dried and preheated aluminum chips in the lower part of the filter. A stirrer that rotates in proximity to the charging means that is charged into the molten metal and a stirrer capable of injecting an inert gas of nitrogen or argon from the rotating shaft is provided, and the stirrer promotes dissolution of the aluminum chips. It is characterized by that.

With this configuration, the aluminum chips charged by the charging means are forcibly stirred and dispersed over a wide range with a stirring blade, and the aluminum chips are dissolved and oil content by finely diffusing the aluminum chips by inert gas injection. Gasification can be promoted.

An aluminum chip melting apparatus according to claim 5 is the aluminum chip melting apparatus according to any one of claims 1 to 4, wherein the charging means is configured so that a discharge end of the drying / preheating screw conveyor is at an upper portion. A connection opening is formed in the upper part of a closed charging hopper provided with a steam discharge valve, and a vertical or inclined charging screw conveyor is provided below the melting part filter of the crucible melting furnace from the lower part of the charging hopper. It is provided so that the lower end is immersed, and the dried and preheated aluminum chips are put into the molten metal by the charging screw conveyor and the inert gas of nitrogen or argon gas from the charging screw conveyor rotary shaft tube. It is characterized by charging in.

By adopting this configuration, when the aluminum chips accompanied by the adhering cutting oil are preheated by the drying / preheating screw conveyor, the moisture is transported in an evaporated state, and when steam is discharged to the charging hopper, Released into the hopper space and dissipated to the atmosphere via a steam discharge valve. Also, preheated aluminum chips containing oil are deposited at the bottom of the charging hopper, and then transported in a filled state by a vertical or inclined charging screw conveyor, and dropped and charged together with an inert gas into the melting part. And bubbling. In addition, the vertical charging screw conveyor is easier to adjust the charging amount than the inclined charging screw conveyor because the charging speed is more likely to change depending on the degree of aluminum chip filling. It is. Further, it becomes possible to enhance the diffusion and melting of the aluminum chips by introducing an inert gas into the rotary screw tube of the charging screw conveyor.

An aluminum chip melting apparatus according to claim 6 is the aluminum chip melting apparatus according to any one of claims 1 to 4, wherein the charging means is configured such that the discharge end of the hermetic screw conveyor is steamed upward. A connection opening is made in the upper part of the closed charging hopper provided with a discharge valve, and an inclined pusher is immersed from the lower part of the charging hopper below the melting part filter of the crucible melting furnace. The dried and preheated aluminum chips are charged into the molten metal by the pusher.

Although it is intermittent by this structure, it becomes possible to forcibly insert the aluminum chips into the molten metal of the melting furnace. Further, according to this pusher, the aluminum chips can be forcibly charged into the melting furnace without being greatly affected by properties such as the particle size of the aluminum chips. In addition, since the charging amount is easily adjusted by the frequency of inserting the pusher, it is easy to control the dissolution amount of the chips.

An aluminum chip melting apparatus according to claim 7 is the aluminum chip melting apparatus according to any one of claims 1 to 6, wherein the oil gasification combustion means includes a melting section and a molten metal of the crucible melting furnace. A pipe connected to the combustion part of the combustion burner from the upper space of the part, and a venturi part connected to the combustion part at the end of the pipe, and the dried and preheated aluminum chips in the melting part of the melting furnace The oily gas generated during melting is collected and attracted to the combustion burner of the melting furnace for burning.

With this configuration, the oil content in the cutting oil accompanying the aluminum chips is gasified and recovered in the melting part of the melting furnace, and is sent to the combustion burner part via the venturi part by piping (duct). It burns with the flame of a combustion burner. This produces the effect of substituting the fuel for the combustion burner.

An aluminum chip melting apparatus according to claim 8 is the aluminum chip melting apparatus according to any one of claims 1 to 7, wherein the drying / preheating means has a temperature at which the aluminum chip is dried / preheated. The temperature range is from 125 ° C to 145 ° C, preferably 135 ° C.

The aluminum chips of the present invention are accompanied by an oil component derived from cutting oil. Normally, this cutting oil is in an emulsion state of oil and water, and the amount thereof is in the range of 5 to 15 wt% for oil and 1 to 5 wt% for water with respect to the cutting oil containing cutting oil. For the purpose of evaporating moisture and leaving the oil component by heating the cutting oil, thermogravimetric-differential thermal analysis (TG-DTA analysis) of the cutting oil to be treated was performed. As a result, it was found that the water was removed by heating up to around 135 ° C., and the oil component was oxidized and generated heat in the region of 200 to 500 ° C. (see FIG. 9). Based on this, by taking the constitution of claim 10, the oil content remains by setting the drying / preheating temperature of the aluminum chips accompanying the cutting oil in the range of 135 ± 10 ° C., preferably 135 ° C. , The moisture can be evaporated, the melting of the aluminum chips in the melting furnace and the gasification of the oil can be carried out while maintaining the high temperature in the melting furnace, and the hydrogen content of the molten aluminum can be reduced. .

Further, an aluminum chip melting apparatus according to claim 9 is the aluminum chip melting apparatus according to any one of claims 1 to 8, wherein the drying / preheating means includes moisture in the aluminum chip after drying / preheating. Is 5% or less, preferably 1% or less.

By adopting this configuration, in the melting of the aluminum chips and gasification of oil in the melting furnace, the amount of water remaining in the charged aluminum chips is reduced, so the melting capacity is reduced without causing a temperature drop in the molten metal. It can be maintained and improved efficiently. In addition, the amount of aluminum chips charged in the melting furnace and the gasification of oil can be more efficiently improved when the water content of the charged aluminum chips is 1% or less.

An aluminum chip dissolving apparatus according to claim 10 is the aluminum chip dissolving apparatus according to any one of claims 1 to 9, wherein a centrifugal oil-water separator is provided upstream of the aluminum chip dissolving apparatus. A pretreatment for reducing the amount of cutting oil adhering to the aluminum chips is performed by an oil / water separator.

With the pretreatment means of this configuration, the cutting oil can be physically separated by a centrifugal oil / water separator and its content can be easily reduced, and then there is a margin in the ability to heat and dehydrate with a screw conveyor that is a drying / preheating means. As a result, it is possible to mainly reduce the moisture in the cutting oil adhering to the aluminum chips and efficiently preheat the chips. Therefore, by adding this centrifugal oil water separator to the aluminum chip dissolving device, the melting capacity of aluminum chips accompanied with cutting oil is improved, or the dissolution of aluminum chips accompanied by excess cutting oil Processing can be enabled. Further, according to this configuration, it is not necessary to use heat energy such as heating in the deoiled water, which contributes to energy saving in terms of dehydration and preheating, and there is no concern about air pollution.

Further, the aluminum chip melting method according to claim 11 is a method of melting the aluminum chip to which cutting oil is adhered, and the aluminum chip is in the range of 125 ° C. to 145 ° C., preferably 135 ° C. The crucible is dried and preheated by indirect heating using the exhaust gas of the crucible melting furnace to evaporate and remove moisture in the cutting oil, and then the dried and preheated aluminum chips are heated with a combustion burner. By charging and melting in molten aluminum in the melting part of the mold melting furnace, the oil content in the cutting oil is gasified, and the gas is supplemented and used as fuel for indirect heating of the crucible melting furnace. The molten aluminum is characterized in that only the molten metal is transferred from the melting part to the molten metal part of the crucible melting furnace to obtain a clean molten aluminum.

With this configuration, it is possible to obtain a molten aluminum with high thermal efficiency by evaporating the accompanying moisture of the aluminum chips accompanied with the cutting oil and dissolving the preheated aluminum chips. In addition, since the oil can be recovered by gasification in a melting furnace and used as a substitute for melting furnace fuel, the method of the present invention is an aluminum chip melting method suitable for resource saving and energy saving. In addition, the accompanying oil content of aluminum chips can be gasified in a high-temperature melting furnace and recovered as fuel in a closed circuit, so there is a risk of causing pollution such as air pollution compared to conventional methods in which oil is simply burned. It also contributes to the reduction of dissolved fuel.

The method for melting aluminum chips according to claim 12 is the method for melting aluminum chips according to claim 11, wherein the dried and preheated aluminum chips are charged into molten aluminum in the melting part of the crucible melting furnace. When dissolved, the mixture is stirred and mixed by a mechanical stirrer or inert gas injection to promote dissolution and oil gasification.

With this configuration, the aluminum chips charged in the melting part are forcibly stirred and dispersed over a wide range, and the aluminum chips are finely diffused by inert gas injection to dissolve the aluminum chips and gasify the oil. Can be promoted.

According to the aluminum chip melting apparatus and the melting method according to claims 1 to 12 of the present invention, a high-quality aluminum melt can be obtained using aluminum chips accompanied by cutting oil as a raw material, and the cutting By efficiently gasifying the oil content of the oil in a closed circuit, a part of the fuel of the melting burner can be replaced. As a result, it is possible to replace dissolved fuel by recovering aluminum resources from the aluminum chips and recovering the energy stored in the associated oil, thereby contributing to resource utilization and energy saving. Further, according to the present invention, in the removal of the accompanying cutting oil, unlike the conventional method, it is an apparatus and method that can perform a clean process without fear of pollution such as air pollution. In addition, this aluminum chip melting device is composed of equipment that has been used in a compact manner, has a smaller installation area than conventional ones, and does not require significant equipment costs. Also excellent equipment.

FIG. 1 is a schematic front sectional view of an aluminum chip melting apparatus according to an embodiment for carrying out the present invention. FIG. 2 is a schematic side cross-sectional view in FIG. FIG. 3 is a schematic cross-sectional view of a flue gas system connected to the drying / preheating device in FIG. 4 is a schematic cross-sectional view taken along the line AA in FIG. FIG. 5 is a schematic front sectional view of an aluminum chip melting apparatus according to another embodiment for carrying out the present invention. FIG. 6 is a schematic front sectional view of an aluminum chip melting apparatus according to another embodiment for carrying out the present invention. FIG. 7 is a schematic cross-sectional view of a flue gas system connected to the drying / preheating device in FIG. 5 or FIG. FIG. 8 is a schematic cross-sectional view taken along the line AA in FIG. It is a typical example of the thermogravimetric-differential thermal analysis chart of the cutting oil for aluminum. It is a figure which shows the effect of the nitrogen gas injection in aluminum chip melt | dissolution. It is a flowchart which shows the melt | dissolution process of the aluminum chip of this invention. It is a prior art example, and is a flowchart which shows the pre-processing method of aluminum chips.

Referring to the flow chart of FIG. 11, the aluminum chip accompanied by the cutting oil according to the present invention will be described based on the flow chart of FIG. 11. Accordingly, the amount of oil and water is reduced by applying to a centrifugal oil-water separator (a). Next, drying and preheating step (b) of the aluminum chips accompanied with cutting oil, charging step (c) of charging the dried and preheated aluminum chips into the melting furnace, and in the melting furnace holding the molten aluminum heated, It comprises a melting step (d) in which chips are charged and melted, and an oil gasification combustion step (e) in which oil gas obtained by gasifying oil in an aluminum melting furnace is burned in a melting furnace combustion burner.

An aluminum chip melting apparatus 1 according to the present invention will be described with reference to FIGS. The aluminum chip melting apparatus 1 is equipped with a drying / preheating device 4 that removes moisture in the cutting oil adhered to the aluminum chip, and the dried / preheated aluminum chip is charged into the molten metal M of the crucible melting furnace 2. An aluminum melting device for producing a molten aluminum M by melting dry and preheated aluminum chips using a chip charging device 5 and a crucible type melting furnace 2 indirectly heated by a combustion burner 6, and dried and preheated aluminum It comprises an oil gasification combustion apparatus in which the oil remaining in the chips is gasified when the aluminum chips are melted in the crucible melting furnace 2 and then attracted to the combustion burner 6 for combustion.

In addition, a centrifugal oil / water separator (not shown) is provided in the preceding stage of the aluminum chip melting apparatus 1 to perform pretreatment to reduce the amount of cutting oil adhering to the aluminum chip, that is, the amount of excess oil moisture. . With this pretreatment means, the excess oil and water content in the cutting oil adhered to the aluminum chips can be easily reduced without physical heating with a centrifugal oil / water separator, and then the aluminum chip melting apparatus 1 is dried and preheated. Since it can be further heated and dehydrated by the screw conveyor 4-2 as a means, the moisture in the cutting oil adhering to the aluminum chips can be efficiently reduced and preheated. Further, according to this apparatus, it is not necessary to use heat energy such as heating in the deoiled water, so there is no concern about air pollution associated therewith.

The aluminum swarf according to the present invention is mainly composed of cutting waste generated when an aluminum product is manufactured by cutting aluminum or an aluminum alloy. Therefore, the aluminum chips are accompanied by 10 to 20 wt% of the cutting oil with respect to the cutting oil containing chips 100, and normally, the cutting oil is an emulsion of oil and water, so that the amount of 5 to 15 wt% is used. A mixture of oil and 1-5 wt% water is adhered. The aluminum chip melting apparatus 1 of the present invention removes moisture by heating and evaporating from the cutting oil associated with the aluminum chip, leaving only the oil content, and then charging it into the melting furnace 2 to melt the aluminum melt M. In addition, the oil is gasified and combusted as a partial alternative fuel for the heating burner 6 of the melting furnace 2. As a result, it is possible to recover aluminum from the aluminum chips and to recover energy as fuel without causing pollution such as air pollution with the accompanying cutting oil.

The drying / preheating device 4 in the aluminum chip melting apparatus 1 is a drying / preheating screw conveyor 4-2 in which aluminum chips are rotated from a charging hopper 4-1 by a variable speed drive geared motor 4-2e. The screw conveyor 4-2 is inserted into the drying / preheating chamber 4-3, and the screw conveyor outer cylinder 4-2b is passed through the combustion exhaust gas duct 8 from the crucible melting furnace 2. During the course, the aluminum chips are dried and preheated by adjusting the temperature with the cold air from the dilution air inlet 8-1 and introducing it into the drying / preheating chamber 4-3 and heating. The flow rate and temperature of the drying / preheating gas are determined by the values of the indoor pressure gauge 4-3d and the thermometer 4-3c provided in the drying / preheating chamber 4-3, and the damper and combustion exhaust gas at the dilution air inlet 8-1. The degree of opening / closing of the damper 8-2 of the duct 8 can be adjusted.

At this time, the temperature for drying and preheating the aluminum chips is in the range of 125 ° C. to 145 ° C., preferably 135 ° C. Normally, aluminum chips are accompanied by oil and moisture derived from cutting oil. Therefore, in the present invention, cutting oil used for the purpose of evaporating moisture by heating and leaving the oil (trade name: cedar cut) Thermogravimetric-differential thermal analysis (TG-DTA analysis) of CS-68DN-2) was performed. As a result, as shown in FIG. 9, it was found that moisture was removed by heating up to around 135 ° C., and the oil was oxidized and generated heat in the region of 200 to 500 ° C. Based on this, when the drying / preheating temperature of the aluminum chips is in the range of 135 ± 10 ° C., preferably 135 ° C., the oil remains and the water can be removed in an evaporated state. Subsequently, when the aluminum chips are used for melting in the melting furnace 2 and gasifying the oil, the melting furnace 2 can maintain a high temperature without lowering the melting temperature, and the hydrogen content of the molten aluminum M can be reduced. It leads to reduction.

Further, as shown in FIG. 3, the crucible type melting furnace 2 of the aluminum chip melting apparatus 1 has a melting furnace combustion chamber 7 surrounded by a furnace wall refractory 7-1 and a furnace lid refractory 7-2. It is installed on the furnace mounting table 2-5. The melting furnace combustion burner 6 is provided at a corner near the bottom of the melting furnace combustion chamber 7, and the combustion exhaust gas outlet is located above the melting furnace combustion chamber 7 as shown in FIGS. Since the axis is shifted, the flame of the combustion burner 6 heats the crucible melting furnace 2 as a swirling flow licking the outer wall of the crucible melting furnace 2 from bottom to top. The crucible melting furnace 2 is mainly formed of a carbonaceous refractory in a bowl shape, holds an aluminum melt M having a melting point of about 660 ° C. inside, and a swirl flow flame from the bottom to the top of the melting furnace combustion burner 6. Therefore, the melting furnace 2 is indirectly heated by the combustion burner 6. Since the melting furnace combustion chamber 7, the furnace upper space 2-4, and the inside of the melting furnace 2 are isolated by the refractory of the melting furnace 2, the atmosphere state is completely different. Usually, the combustion chamber temperature of the melting furnace is in the range of 700 ° C to 1000 ° C. The size of the crucible melting furnace 2 is about 600 mm in diameter and about 500 mm in height when the melting amount of aluminum chips is 50 to 100 kg / hr.

As shown in FIGS. 4 and 8, the crucible melting furnace 2 of the aluminum chip melting apparatus 1 is connected to the molten metal pan 3 by a refractory partition wall 2-2 in the depth direction of the molten metal M pool. 1 is divided into a melted portion 2-b and a melted portion 2-a, and further below the surface of the melted portion 2-a as shown in FIGS. A refractory filter 2-3 is provided over the entire horizontal cross section. As for the melting of the aluminum chips, the dried and preheated aluminum chips are accompanied by an inert gas such as nitrogen or argon by the vertical or inclined charging screw conveyor 5-2 of the charging device 5 or the inclined pusher. 5-4 is charged into the molten metal M at the lower part of the filter 2-3 of the melting furnace 2 to melt the aluminum chips and gasifies the oil derived from the cutting oil accompanying the aluminum chips. -A is discharged from the upper surface, oil gas is taken out through the furnace upper space 2-4, and supplied to the auxiliary combustion of the combustion burner 6 through the oil recovery duct 9.

Further, in the melting part 2-a of the crucible type melting furnace 2, a stirring blade rotating in the vicinity of the charging means 5 for charging the dried and preheated aluminum chips into the molten metal M below the filter 2-3. A stirrer 3 including a 3-1 and a rotating shaft 3-3 is provided. Further, the stirrer 3 can inject an inert gas of nitrogen from the rotating shaft 3-3, and the aluminum chips charged by the stirrer 3 are forcibly dispersed with a stirring blade 3-1 over a wide range. At the same time, by finely diffusing the aluminum chips by inert gas injection, dissolution of the aluminum chips and gasification of the oil can be promoted.

FIG. 10 shows the result of confirming the effect of nitrogen (N ₂ ) injection on the dissolution of the above-described aluminum chips in the molten aluminum M in an experimental furnace. As the aluminum chips, chips having a water content of 1% or less and an oil content of 1.5 to 2% after drying were used. As a result, in the case of no nitrogen injection, the elapsed time after charging aluminum chips was 10 to 20 minutes, and the dissolved ratio (dissolution efficiency) was 50 to 65%. A dissolution rate (dissolution efficiency) of 65 to 85% was obtained in 3 to 10 minutes after the charging. From these, by performing nitrogen (N ₂₎ injection in the aluminum melt M, the dissolution of aluminum chips was confirmed the possibility of achieving in a short time efficiently.

Further, the chip charging device 5 of the aluminum chip melting apparatus 1 is opened by connecting the discharge end 4-2d of the drying / preheating screw conveyor 4-2 to the upper part of the hermetic charging hopper 5-1. In addition, a steam discharge valve 5-3 is provided in the upper lid portion of the charging hopper 5-1. Also, a vertical or inclined charging screw conveyor 5-2 that is rotationally driven by a variable speed drive geared motor 5-2d from the lower portion of the charging hopper 5-1 is a melting part filter of the crucible melting furnace 2. 2-4 is provided so that its lower end is immersed, and dried and preheated aluminum chips are charged into the molten metal M by the charging screw conveyor 5-2, and nitrogen, which is an inert gas, is used at that time. Is injected from the nitrogen inlet 5-2e through the tubular charging screw conveyor rotary shaft 5-2c and injected into the molten metal M from the nitrogen outlet 5-2f to dissolve the charged aluminum chips. And promote the gasification of oil. Moreover, the degassing action from the molten metal M is also brought about. Further, since the outer casing 5-2b and the screw blade 5-2a of the charging screw conveyor 5-2 are in contact with the molten aluminum M, fire resistance is required. When the vertical or inclined charging screw conveyor 5-2 is adopted, the aluminum chips fill up the spiral space of the screw blade 5-2a. Since the inlet hopper 5-1 and the melting furnace 2 are completely sealed, the air and water vapor of the charging hopper 5-1 do not flow into the melting furnace 2, so that the quality of the molten metal M is not adversely affected. In addition, the vertical charging screw conveyor is more susceptible to changes in the charging speed depending on the degree of aluminum chip filling compared to the inclined charging screw conveyor. Adjustment is easy.

In addition, as shown in FIG. 6, an inclined pusher 5-4 can be provided in place of the vertical or inclined charging screw conveyor 5-2. The inclined type pusher 5-4 is used for melting the crucible melting furnace 2 from the lower part of the charging hopper 5-1 to which the hermetic screw conveyor 4-2 is connected to the upper part of the hermetic charging hopper 5-1. The lower end of the partial filter 2-3 is provided so that its lower end is immersed, and dried and preheated aluminum chips can be charged into the molten metal M by the pusher 5-4. Although it is intermittent by this inclined type pusher 5-4, it becomes possible to forcibly insert aluminum chips into the molten metal M of the melting part 2-a of the melting furnace 2. Further, according to the inclined pusher 5-4, it is possible to forcibly charge the aluminum chips into the melting furnace 2 without being greatly affected by the properties such as the particle size of the aluminum chips. Further, it is preferable that the inclined pusher 5-4 is driven by an air-driven rodless cylinder 5-4a. Also, the pusher tip 5-4b of the inclined pusher 5-4 is cut obliquely so that the aluminum chips can be easily pushed into the molten metal M. Further, since the charging amount can be easily adjusted by the charging frequency of the pusher 5-4, it is easy to control the dissolution amount of the chips.

Further, the oil gas that has been gasified in the melting furnace 2 of the aluminum chip melting apparatus 1 and accumulated in the furnace upper space 2-4 is recovered from the gas from the furnace upper space 2-4 to the combustion part of the combustion burner 6. Since the duct 9 is provided and the venturi section 9-1 connected to the combustion section is provided at the end of the oil gas recovery duct 9, the oil gas generated from the melting furnace 2 is attracted and guided, and the melting furnace combustion burner 6 Can be burned in a flame. Thereby, a partial replacement of the fuel for the melting furnace combustion burner 6 becomes possible.

Moreover, when the melting operation | work using the aluminum chip melting apparatus 1 which concerns on this invention is described generally, the cutting oil containing aluminum cutting powder can select the pre-processing of a centrifugal oil-water separator according to the amount of cutting oil contained. Then, the aluminum chips accompanied with the cutting oil are dried and preheated by indirect heating to a range of 125 ° C. to 145 ° C., preferably 135 ° C., to evaporate and remove moisture in the cutting oil, and then the drying -The preheated aluminum chips are charged into the melting part 2-a of the crucible melting furnace 2 heated by the combustion burner 6 and melted, whereby the oil in the cutting oil is gasified and the gas is melted into the crucible. The molten aluminum is used as a fuel for the combustion burner 6 of the furnace 2, and the molten aluminum is transferred only from the melting part 2-a of the crucible melting furnace 2 to the molten metal part 2-b to obtain a clean molten aluminum M It is get those.

In the drying / preheating process of the aluminum chips that are the raw material, the outer cylinder 4-2b of the drying / preheating screw conveyor 4-2 is heated with melting furnace combustion exhaust gas at a predetermined temperature, so that the conveying aluminum cutting of the screw conveyor 4-2 is performed. The powder is accompanied by evaporation of moisture, while the oil is not evaporated, and the aluminum chips are preheated and sent to the charging hopper 5-1 of the next-stage chip charging apparatus 5. When the dried and preheated aluminum chips from the drying / preheating screw conveyor 4-2 are discharged to the charging hopper 5-1, the water vapor is discharged into the hopper space and passes through the steam discharge port 5-3. To the atmosphere. The preheated aluminum chips containing oil are deposited in the charging hopper 5-1 and then charged into the melting furnace 2.

Aluminum chips accompanied by oil are conveyed in a filled state from a charging hopper 5-1 by a vertical or inclined screw conveyor 5-2, and are moved to the lower area of the filter 2-3 of the melting part 2-a of the melting furnace 2. Then, it is charged together with an inert gas ejected through the screw rotating shaft 5-2c. Further, the aluminum chips are bubbling of the inert gas injection and the diffusion of the stirrer 3 by the stirring of the stirrer blade 3-1 of the stirrer 3 and the injection of the nitrogen gas outlet 3-3 of the rotating shaft 3-2. As a result, the oil melts more quickly to become the molten metal M, and the oil is gasified. Next, the molten aluminum M passes under the partition wall 2-2 and moves to the molten metal part 2-b, and finally is discharged from the hot water tank 2-1. At this time, the molten metal M is prevented from flowing due to a short circuit by the partition wall 2-2, and by taking a long residence time, the molten metal M is sufficiently cleaned by levitating and separating impurities such as slag components. Further, the oil component is heated in the region under the filter 2-2 under the bubbling of the inert gas to be gasified without being oxidized, passes through the filter 2-2, floats up, and passes through the furnace upper space 2-4. Then, the fuel is replaced by the fuel by being attracted by the venturi section 9-1 in the combustion zone of the combustion burner 6 via the oil gas recovery duct 9 and burned, thereby contributing to energy saving and fuel saving.

Separately, the aluminum chips accompanied with oil are intermittently forced from the charging hopper 5-1 by the inclined charging pusher 5-3 to filter the aluminum chips in the melting part 2-a of the melting furnace 2. 2-3 Can be charged into the molten metal M in the lower area. In addition, the charged aluminum chips are rapidly melted by diffusion by the stirring of the stirring blade 3-1 of the adjacent stirrer 3 and the injection of the nitrogen gas outlet 3-3 of the rotating shaft 3-2. As it becomes M, the oil is gasified. Next, the molten aluminum M passes under the partition wall 2-2 and moves to the molten metal part 2-b, and finally is discharged from the hot water tank 2-1. At this time, the molten metal M is prevented from flowing due to a short circuit by the partition wall 2-2, and by taking a long residence time, the molten metal M is sufficiently cleaned by levitating and separating impurities such as slag components. Further, the oil component is heated in the region under the filter 2-2 under the bubbling of the inert gas to be gasified without being oxidized, passes through the filter 2-2, floats up, and passes through the furnace upper space 2-4. Then, the fuel is replaced by the fuel by being attracted by the venturi section 9-1 in the combustion zone of the combustion burner 6 via the oil gas recovery duct 9 and burned, thereby contributing to energy saving and fuel saving.

The cutting oil contained in the aluminum chips includes cutting oil mainly composed of oil that does not contain water, apart from the oil composed of the oil and water targeted by the present invention. The aluminum chip melting apparatus and the melting method of the present invention can be sufficiently applied to aluminum chips containing cutting fluid having no moisture. In this case, there is no need for energy to evaporate water as much as it does not contain water, the preheating temperature of the aluminum chips themselves is likely to rise, the processing capacity of the aluminum chips by this device is easy to improve, and the heat required for melting It becomes easy to save energy.

As described above, the molten aluminum M can be obtained with high thermal efficiency by using the aluminum chips accompanied with the cutting oil as a raw material, evaporating the accompanying moisture, and dissolving the preheated aluminum chips. In addition, since the oil component is gasified and recovered in the melting furnace 2 and can be used as a substitute for the fuel in the melting furnace 2, the present invention is an aluminum chip melting apparatus and method suitable for resource saving and energy saving.

Not only can it be used in the field of processing aluminum chips, but it can also be applied in the field of processing of zinc, magnesium metal and their alloy chips.

1: Aluminum chip melting device
2: crucible melting furnace 2-a: melting part 2-b: molten metal part 2-1: tapping pot 2-1b: molten metal pan 2-2: partition wall 2-3: filter 2-4: furnace upper space 2-5 : Furnace mounting table 3: Stirrer 3-1: Stirring blade 3-2: Rotating shaft 3-3: Nitrogen gas outlet 3-4; Nitrogen gas pipe 4: Drying / preheating device 4-1: Charge hopper 4- 2: Screw conveyor 4-2a: Screw blade 4-2b: Conveyor cylinder 4-2c: Loading section 4-2d: Discharge end 4-2e: Drive geared motor 4-3: Drying / preheating chamber 4-3a: Gas Inlet 4-3b: Gas outlet 4-3c: Thermometer 4-3d: Indoor pressure gauge 5: Chip charging device 5-1, charging hopper 5-2: charging screw conveyor 5-2a: screw blade 5-2b : Conveyor outer cylinder 5-2c: Screw rotating shaft 5-2d: Drive geared motor 5-2e Blowing nitrogen inlet 5-2F: nitrogen blowing mouth 5-3: steam discharge valve 5-4: loading pusher 5-4A: driving rodless cylinder 5-4B: pusher tip 6: melting furnace combustion burner
7: Melting furnace combustion chamber 7-1: Furnace wall refractory 7-2: Furnace lid refractory 8: Combustion exhaust gas duct 8-1: Dilution air inlet 8-2: Damper 9: Oil gas recovery duct 9-1: Induction Venturi M: Molten metal

Claims

Drying / preheating means for removing moisture in cutting oil, charging means for charging the dried / preheated aluminum chips into the molten metal of the crucible melting furnace, and indirect heating with a combustion burner An aluminum melting means for producing a molten aluminum by melting the dried and preheated aluminum chips using the crucible melting furnace, and the oil remaining in the dried and preheated aluminum chips is removed from the crucible. An aluminum chip melting apparatus comprising oil gasification combustion means that gasifies and melts the aluminum chips in a mold melting furnace and induces them into the combustion burner for combustion.
The drying / preheating means conveys the aluminum chips by a dry / preheating screw conveyor in which aluminum chips are sealed, and heats the outer peripheral wall of the screw conveyor by adjusting the temperature of the combustion exhaust gas from the crucible melting furnace. The aluminum chip melting apparatus according to claim 1, wherein the chip is dried and preheated.
The crucible type melting furnace is divided into a molten metal part connected to a tapping pot by a refractory partition in the depth direction of the molten metal pool, and a molten part, and a horizontal cross section below the molten metal surface of the molten part A filter made of refractory material is provided throughout, and the dried and preheated aluminum chips are charged into the molten metal under the filter by the charging means to dissolve the aluminum chips, and the aluminum chips. 3. The aluminum chip melting apparatus according to claim 1, wherein an oil component derived from a cutting oil accompanying the powder is gasified and the oil component gas is taken out from the upper surface of the melting portion and used for combustion of the combustion burner.
The melting part of the crucible melting furnace is in close proximity to the charging means for charging the dried and preheated aluminum chips into the molten metal under the filter, and a rotating stirring blade and nitrogen or argon from the rotating shaft An aluminum chip melting apparatus according to claim 3, further comprising a stirrer capable of injecting said inert gas, wherein the stirrer promotes dissolution of the aluminum chip.
The charging means has a discharge opening of the drying / preheating screw conveyor connected to an upper portion of a closed charging hopper provided with a steam discharge valve at an upper portion, and is formed in a vertical or inclined manner from the lower portion of the charging hopper. A mold charging screw conveyor is provided so that its lower end is immersed below the melting part filter of the crucible melting furnace, and the dried and preheated aluminum chips are fed into the charging screw conveyor by nitrogen or argon gas. 5. The aluminum chip melting apparatus according to claim 1, wherein both of the inert gas are charged into the molten metal from the charging screw conveyor rotary shaft tube.
The charging means has a discharge opening of the closed screw conveyor connected to an upper portion of a closed charging hopper provided with a steam discharge valve at an upper portion, and an inclined pusher is provided from the lower portion of the charging hopper. 5. The crucible type melting furnace is provided so that a lower end thereof is immersed below a melting part filter, and the dried and preheated aluminum chips are charged into the molten metal by the pusher. The aluminum chip melting apparatus according to any one of the above.
The oil gasification combustion means includes a pipe connected to the combustion part of the combustion burner from an upper space of the melting part and the molten metal part of the crucible melting furnace, and a venturi part connected to the combustion part at the end of the pipe The oil gas generated when the dried and preheated aluminum chips are melted in the melting section of the melting furnace is collected and attracted to the combustion burner of the melting furnace to be burned. To 6. The aluminum chip melting apparatus according to any one of 6 to 6.
8. The drying / preheating means for drying / preheating the aluminum chips in a range of 125 [deg.] C. to 145 [deg.] C., preferably 135 [deg.] C. Aluminum chip melting equipment.
The aluminum according to any one of claims 1 to 8, wherein the drying / preheating means makes the moisture of the aluminum chips after the drying / preheating treatment 5% or less, preferably 1% or less. Chip melting device.
The centrifugal oil / water separator is provided in the preceding stage of the aluminum chip dissolving device, and the pretreatment for reducing the amount of cutting oil adhering to the aluminum chip is performed by the centrifugal oil / water separator. An aluminum chip melting apparatus according to claim 1.
A method for melting aluminum chips to which cutting oil is adhered, wherein the aluminum chips are indirectly heated to 125 ° C. to 145 ° C., preferably 135 ° C., using the exhaust gas from a crucible melting furnace. Then, the moisture in the cutting oil is evaporated and removed, and then the dried and preheated aluminum chips are charged into the molten aluminum in the melting portion of the crucible melting furnace heated by a combustion burner. As a result, the oil in the cutting oil is gasified and used as a fuel for indirect heating of the crucible melting furnace, and the dissolved aluminum is used as a melting part of the crucible melting furnace. A method for melting aluminum chips, wherein only molten metal is transferred from a molten metal to a molten metal portion to obtain a clean molten aluminum.
When the dried and preheated aluminum chips are charged and melted in the molten aluminum in the melting part of the crucible melting furnace, they are stirred and mixed by a mechanical stirrer or inert gas injection to dissolve and gasify the oil. The method for melting aluminum chips according to claim 11, wherein the method is promoted.