HK1198965B - Method for recovering metal copper from copper wires coated with chlorine-contained synthetic resin - Google Patents

Description

Method for recovering metallic copper from copper wire coated with chlorine-containing synthetic resin

Technical Field

The present invention relates to a method for recovering metallic copper from wastes including chlorine-containing synthetic resins and copper, and more particularly, to a method for recovering metallic copper from waste covered copper wires (unnecessary covered wires) using oil such as waste oil. The present invention provides a technique for recovering metallic copper useful as a method for treating waste copper wires using a chlorine-containing resin such as a vinyl chloride resin (chlorine-containing resin causes environmental pollution when incinerated, and deterioration of an incinerator), and the present invention is a technique for heating waste oil as a heat medium to dechlorinate the resin and carbonize the resin, thereby facilitating separation of the resin from the metallic copper.

Background

Since a large amount of various plastics are used in China, the development of a technology for recycling used plastics by treating the used plastics is an important issue. As a method for recycling used plastic products, there have been developed: a method of reusing the resin material as the same product or another plastic product, a method of producing a chemical raw material such as synthetic gas or decomposed oil by thermal decomposition at a high temperature, a method of reusing the resin material by converting the resin material into another chemical substance such as a monomer by chemical decomposition, or a method of using the resin material as a fuel for steam, power generation, a cement kiln, or the like.

Among various plastics, the handling and recycling of chlorine-based plastic articles is particularly problematic. In our country, about 170 ten thousand tons of polyvinyl chloride resin is produced in one year, and polyvinyl chloride resin has excellent properties such as flame retardancy, durability, oil resistance, chemical resistance, electrical insulation, strength, flame retardancy, weather resistance, freedom of coloring, low cost, and adhesion welding, and is often used in building materials, wire coatings, and electric appliances by being integrated with metals. In the 90 s of the 20 th century, chlorine-based plastics including polyvinyl chloride resins were considered as a main generation source of dioxins, and thus have been a social problem. At present, dioxin is considered to be generated not only from chlorine-based plastics but also from incomplete combustion in incineration treatment of wastes containing chlorine and aromatic compounds. As a countermeasure, there have been proposed a method of reducing the incomplete combustion rate by improving the performance of the incinerator, a method of separating chlorine-containing garbage without incineration (expansion of the recycling system), a method of reducing the amount of chlorine-containing plastics used, and the like. However, since polyvinyl chloride resins have very different chemical properties compared to other general hydrocarbon resins, recycling of resins is likely to cause an obstacle if polyvinyl chloride is mixed therein.

If organic chlorine-based resins such as polyvinyl chloride are incinerated, the generated hydrogen chloride may damage the apparatus. In particular, since the hydrogen chloride gas flows into the vicinity of the condenser together with the low-molecular decomposition gas in the thermal decomposition device, the region of damage caused by the hydrochloric acid is wide. Therefore, this processing apparatus cannot perform a thermal decomposition process on an organochlorine resin such as a vinyl chloride resin. Therefore, several techniques for dechlorinating a vinyl chloride resin and techniques for treating a vinyl chloride resin without high-temperature treatment have been proposed.

For example, as a method for dechlorinating waste plastics, which can dechlorinate at a relatively low temperature in a short time and selectively decompose bonds between carbons in a molecule, thereby reducing a residual chlorine concentration and improving a fuel yield, the following method for dechlorinating plastics is proposed: waste plastics containing chlorine-based resins such as polyvinyl chloride and polyvinylidene chloride are melt-kneaded, and the waste plastics in a molten state are irradiated with ultraviolet rays by a mercury lamp to discharge hydrogen chloride generated by a photodecomposition action and a thermal decomposition action (patent document 1).

In addition, when hydrochloric acid and oil are separated and recovered from an organochlorine resin, a dechlorination device for separating chlorine gas by heating the organochlorine resin to 300-350 ℃ and a gasification modification device for decomposing low-molecular-weight oil by heating the residue to 400-450 ℃ in a catalyst are separated, and the chlorine gas separated in the dechlorination device is cooled by water in a hydrochloric acid recovery device and recovered as hydrochloric acid. An organochlorine resin treatment apparatus has been proposed which is capable of evaporating a part of oil, burning a combustible gas in a gas combustion chamber, and reusing the combustion exhaust gas as a heat source for each part, and which is simplified, reduced in size, low in cost, and energy-saving (patent document 2).

Further, there are reports that: a method of dechlorinating a plastic mixture by heating the plastic mixture to 200 to 350 ℃ in an aliphatic hydrocarbon (heavy oil, light oil, kerosene) or an aromatic hydrocarbon (naphtha, creosote, anthracene oil, coal tar) or the like which is a solvent capable of dissolving or swelling the plastic (patent document 3); in recycling waste plastics containing chlorine-based plastics such as polyvinyl chloride, the dechlorination effect of triethylene glycol is the most excellent in dechlorination treatment using ethylene glycol, diethylene glycol, triethylene glycol, and propylene glycol as solvents and KSCN as a nucleophile in the presence of alkali.

In addition, in the treatment of a product in which an organic chlorine-based resin and a metal are mixed or integrated, a more difficult step of separating the resin and the metal is required in addition to the dechlorination treatment.

A technique for treating waste or products in which organic materials such as plastics and valuable metals such as ferrous or non-ferrous metals are mixed basically comprises treatment of organic materials and recovery of valuable metals. Among the dry methods which have been widely used in the past, there are incineration methods and thermal decomposition methods as organic material treatment techniques, and there are magnetic separation methods for recovering iron, eddy current separation methods for recovering nonferrous metals, and wind separation methods for separating copper and aluminum as valuable metal recovery techniques. However, these conventional methods cannot actually separate metal and plastic completely and efficiently, and cannot selectively recover a copper wire such as a coated copper wire or an enameled wire. It is conceivable to add a step of discriminating by wind, a specific gravity liquid, a metal detector, a stainless steel with a super strong magnet, a wind shaker type specific gravity, etc., but the problem that the copper wire cannot be recovered is not solved. In recent years, unnecessary covered wiring has increased year by year. Since the coated wiring having a large diameter has high recycling efficiency, the metal is recycled by burning at high temperature or mechanically removing the coating, but the amount of metallic copper that can be recovered in the case of thin wires is small, and the cost is not cost-effective by the above method, and therefore the wiring is currently disposed of as industrial waste.

As a technique of the wet method, a wet oxidation method, a supercritical water decomposition method, a supercritical water oxidation method, or the like is known as a technique of treating an organic matter. As for the treatment of organic substances, there is a problem in the use for organic chlorine resins, in which decomposition treatment using high-temperature hot water such as supercritical water oxidation requires pulverization of organic substances such as plastics to have a particle size of about 0.1mm due to decomposition in water, and also requires separation and removal of valuable metals such as nonferrous metals and copper wires having a particle size of 5mm or less, which are difficult to separate in a conventional separation apparatus, in advance with high efficiency in order to prevent accumulation and clogging in a reaction vessel, and also requires removal of chlorine-containing plastics such as polyvinyl chloride in advance with high efficiency. As described above, no practical technique has been developed so far for separating industrial waste containing organochlorine resins and metals into metals and resins and effectively utilizing both.

On the other hand, a large amount of waste oil is produced in China, and the treatment and regeneration technology thereof becomes an important subject. For example, lubricating oils are widely used in driving devices such as internal combustion engines, vehicles, machine tools, and industrial machines, and in particular, in recent years, automobiles have been popularized due to motorization (motorization), and operations have been mechanized to solve insufficient human hands, so that the consumption of engine lubricating oils, cylinder oils, hydraulic oils, extreme pressure lubricating oils, cutting oils, and the like has increased dramatically. These lubricating oils become waste oils when their properties deteriorate after a considerable period of use, but the following methods are adopted: a method of removing deteriorated components and contaminants of deteriorated oil (cutting oil, gear oil, quenching oil, etc.) and reusing them as a lubricant; a method of performing treatment to enable it to be used as a substitute for heavy oil; a method for use as an auxiliary fuel for a kiln or the like; a method of performing incineration treatment or the like.

For example, when used lubricating oil is used as fuel, various additives including heavy metals are mixed in the lubricating oil, and therefore, when used lubricating oil containing heavy metals is directly reused as boiler fuel or the like, heavy metals are contained in ash, which causes environmental pollution. Therefore, a technique for removing heavy metals from used lubricating oil has been proposed (for example, see patent document 4).

Documents of the prior art

Patent document

Patent document 1: japanese patent laid-open publication No. 2002-53697

Patent document 2: japanese patent laid-open No. 2001-170608

Patent document 3: japanese laid-open patent application No. 2001-72794

Patent document 4: japanese laid-open patent publication No. 5-9492

Disclosure of Invention

Problems to be solved by the invention

Before dioxin becomes a problem, a technique of burning and removing the coated vinyl chloride resin by general incineration and taking out the remaining metallic copper is generally employed. After the damage of dioxin was just pointed out, metallic copper was taken out by burning under high temperature condition of 900 ℃ or higher without generating dioxin. However, this method not only increases the cost of the incinerator, but also causes the durability of the furnace material inside the incinerator to be insufficient, resulting in high fuel costs. Further, if the incinerator is stopped halfway, dioxin is generated at the time point when the temperature in the incinerator is reduced to 900 ℃ or lower, and therefore, the operation must be maintained at all times. In recent years, a device for mechanically stripping a coating of a large-diameter coated copper wire has been used, but the efficiency of a thin wire is too low, and thus the thin wire cannot be practically used. In addition, in the case of low-temperature incineration, a technique of optimizing the atmosphere and pressure in the furnace and a technique of reducing the generation of dioxin by using a catalyst have been disclosed, but a large-scale vacuum system is required to increase the size of the incinerator itself, or the catalyst is expensive, so that it is impossible to prevent an increase in cost. In addition, there is a problem that separation of the treated copper metal and the coated modified product is difficult.

The present invention has an object to develop and provide a novel method capable of recovering metallic copper from waste covered copper wire in which organic materials such as chlorine-containing waste plastics and the like are mixed with metallic copper and the like.

Means for solving the problems

In order to solve the above problems, the present invention provides the following means.

(1) A method for recovering metallic copper from waste of a coated copper wire, characterized in that the waste of a coated copper wire containing a chlorine-containing synthetic resin as a coating material is subjected to a heat treatment at 130 to 300 ℃ in an oil and/or in a nitrogen atmosphere or under a reduced pressure of 0.3 atm or less without using an oil, thereby carbonizing the coating material and reducing the chlorine content thereof, and then the coating material and the copper wire are separated to recover the copper wire.

(2) The method for recovering metallic copper from waste covered with copper wire according to the item (1), wherein the heating treatment is performed in oil at 130 to 300 ℃ and then the heating treatment is performed at 130 to 300 ℃ in a nitrogen atmosphere or under a reduced pressure of 0.3 atm or less without using oil.

(3) The method for recovering metallic copper from waste covering copper wire according to the item (1), wherein the heating treatment in oil is carried out in the presence of an alkaline substance when the heating treatment is carried out at 130 to 300 ℃.

(4) The method for recovering metallic copper from waste covered with copper wire according to the above (1), wherein the covering material after the copper wire is recovered is further subjected to a heat treatment in oil to further reduce the chlorine content and is recovered as a carbon-based fuel.

(5) The method for recovering metallic copper from waste covering copper wire according to item (1), wherein the chlorine-containing synthetic resin is polyvinyl chloride, polyvinylidene chloride, a copolymer of vinyl chloride, a chlorinated resin, or a mixture of a chlorine-containing synthetic resin and another resin.

ADVANTAGEOUS EFFECTS OF INVENTION

According to the present invention, dechlorinated chlorine-containing synthetic resin and metallic copper can be recovered from waste containing chlorine-containing synthetic resin and metallic copper. In particular, it is suitable for recovering metallic copper from waste copper-clad wires and oils using chlorine-containing resins (chlorine-containing resins have problems such as environmental pollution and deterioration of incinerators when incinerated). That is, the coating material resin can be carbonized and embrittled by the heat treatment, and the metallic copper can be easily recovered from the carbide-coated copper wire.

In addition, by treating the waste coated copper wire and the waste oil in combination, the metallic copper can be recovered without generating harmful substances such as dioxin. For example, the dioxin concentration in the treated product after the 0.1-atmosphere heat treatment under reduced pressure in the present invention may be 1/100 or less, which is a concentration at which industrial waste treatment can be performed. By boiling the coating resin in oil, the generation of dioxin can be suppressed, and the separation of the coating resin and the metallic copper can be facilitated. The carbide produced can be used as a solid fuel by press molding. Further, the oil such as waste oil used in the present invention can be reused as fuel or the like.

Drawings

Fig. 1 is a flowchart showing an overall outline of the present invention.

FIG. 2 is a graph showing the relationship between the chlorine content in a vinyl chloride resin and the heat treatment time in the case where calcium hydroxide coexists or does not coexist in the heat treatment. In the figure, [ A measurement ] indicates heat treatment at 230 ℃ in a turbine oil; [ B measurement ] indicates a heating treatment at 230 ℃ with lime added to the turbine oil; [ degreasing ] is a treatment of removing oil components adhering to oil by a primary treatment with a surfactant (detergent) by washing. [ prediction (natural logarithm) ] represents a prediction value in terms of a natural logarithm.

Fig. 3 is a flowchart showing an outline of the whole of the present invention in which the carbide is also used as a fuel by adding three treatments.

FIG. 4 is a graph illustrating the chlorine content in the carbide after the three treatments of FIG. 3.

Detailed Description

Conventionally, it has been difficult to develop an economically safe and appropriate treatment method for wastes containing chlorine-containing synthetic resins and metallic copper, and the present invention provides a novel waste treatment technique capable of recovering metallic copper from wastes containing chlorine-containing synthetic resins and metallic copper. Specifically, the present invention is a method for recovering metallic copper from wastes containing chlorine-containing synthetic resins and metallic copper by subjecting the wastes containing chlorine-containing synthetic resins and metallic copper to a heat treatment in oil and/or a heat treatment under non-oxygen conditions to thereby dechlorinate and carbonize the chlorine-containing synthetic resins, and thereafter separating the metallic copper species from the carbonized chlorine-containing synthetic resins.

By carrying out the present invention, by treating waste containing chlorine-containing synthetic resin and metallic copper, not only metallic copper as a useful resource can be recovered, but also when used as a treatment oil, there is an advantage that the waste oil is effectively utilized. Various mineral oils, vegetable oils, and animal oils can be used as the waste oil, and the quality of the waste oil is not particularly limited, and waste oils having a high degree of contamination or deterioration (which can be used only as fuel) can be used. The waste oil used in the process of the present invention can be further reused as a fuel or the like. In addition, the copper recovered in the present invention has a high purity, and therefore, has an advantage of being easily reused. Further, the coating material after the copper wire recovery is further subjected to a heat treatment in oil to further reduce the chlorine content, and thus can be used as a carbon fuel containing a trace amount of chlorine with a chlorine content of 1%, preferably less than 0.3%, or can be mixed with another fuel to be used as a regeneration fuel.

The waste containing the chlorine-containing synthetic resin and the metallic copper used in the present invention is not particularly limited in its form as long as both are contained. For example, the waste may be a waste in which a chlorine-containing synthetic resin is integrated or bonded with copper metal, and typical examples thereof include electric wires; alternatively, the waste containing the chlorine-containing synthetic resin mixed with the metal may be, for example, waste of vinyl chloride resin mixed with waste metallic copper generated in other cases and difficult to separate, or may be waste containing synthetic resins other than the chlorine-containing synthetic resin.

Fig. 1 shows an outline of an example of the present invention for recovering metallic copper from waste covered wiring. In this example, the step of separating and recovering metallic copper from waste covered wiring includes a primary treatment and a secondary treatment: wherein the primary treatment comprises coating the wiring with industrial waste, and heating in waste oil to heat the coating material containing chlorine synthetic resin; the secondary treatment is a heat treatment under non-oxygen conditions. These heat treatments can achieve the intended purpose of the present invention even if they are carried out separately.

[ chlorine-containing resin ]

Specific examples of the chlorine-containing synthetic resin that can be treated in the present invention include vinyl chloride resins such as polyvinyl chloride resins, polyvinylidene chloride resins, vinyl chloride-ethylene copolymers, and vinyl chloride-vinyl acetate copolymers, copolymer resins of vinylidene chloride, chlorinated polyethylene, chlorinated rubber, chlorinated polyether, and mixtures of chlorine-containing synthetic resins with other resins.

[ oil ]

The process of the present invention is carried out by subjecting the oil to a primary treatment and/or a secondary treatment under non-oxygen conditions such as reduced pressure. The oil functions as a heat medium for the chlorine-containing synthetic resin and also as a receptor for chlorine substances dechlorinated from the chlorine-containing synthetic resin, and contributes to dechlorination and carbonization of the coating material. Waste or virgin oils may be used.

In general, studies on the utilization of waste oil have been actively conducted as they are directly reused as energy resources, and particularly, it is not practical to utilize the solvent function of stable waste oil having a high boiling point such as turbine oil. The waste oil is not particularly limited as long as it is an oil that promotes dechlorination as a heat medium for the chlorine-containing synthetic resin, and if it is an oil in which heavy metals and the like are dissolved, an oil from which heavy metals are removed is preferable.

The oil is selected from mineral oil, vegetable oil and fat, and animal oil and fat. Examples of the mineral oil include a lubricating oil such as a turbine oil, an engine oil, a shaft lubricating oil, a gasoline engine lubricating oil, or a diesel engine lubricating oil, an insulating oil, a cutting oil, a hydraulic working oil, a compressor oil, and a fuel oil.

Examples of the vegetable oil and fat include waste oils such as soybean oil, cottonseed oil, palm oil, safflower oil, olive oil, coconut oil, sesame oil, rapeseed oil, corn oil, sunflower oil, rice bran oil, safflower oil, tung oil, camellia oil, castor oil, linseed oil, peanut oil, cocoa oil, corn oil, and gibberba oil; examples of the animal fat and oil include beef tallow, lard, horse oil, sheep oil, milk fat, cuttlefish oil, herring oil, sardine oil, cuttlefish oil, whale oil, and the like.

[ Heat treatment of chlorine-containing synthetic resin ]

The heat treatment in the waste oil is dechlorination and carbonization, and is also a treatment for embrittling the coating material resin. The treatment of the chlorine-containing synthetic resin is carried out by boiling waste (for example, coated copper wire) containing the chlorine-containing synthetic resin and metal in waste oil (for example, turbine oil) at 130 to 300 ℃, preferably 140 to 250 ℃ for 0.1 to 10 hours, preferably 0.1 to 2 hours. The heat treatment is usually carried out under normal pressure or reduced pressure. In the heat treatment process, for example, the coated copper wire having chlorine-containing synthetic resin as a coating material is boiled in waste oil or fried in waste oil, the coating resin is carbonized and dechlorinated by heat, and bubbles generated enter a gap between the coating resin and the metal copper to easily separate them.

The chlorine-containing synthetic resin is heated further during the heat treatment, for example, from the softening of the chlorine-containing synthetic resin, to thereby initiate dechlorination. Chlorine evaporates and can therefore be recovered as hydrogen chloride. The dechlorinated resin residue is carbonized and finally reused as a fuel. Heating the chlorine-containing synthetic resin together with the waste oil to preferably 140 to 250 ℃ to convert chlorine contained in the chlorine-containing synthetic resin into hydrogen chloride, thereby obtaining a dechlorinated resin residue. For example, it was confirmed that 90% or more of chlorine in vinyl chloride resin can be decomposed and removed by boiling the coating material together with turbine oil in waste oil by analyzing the coating material with a fluorescent X-ray device. A part of the decomposed chlorine was extracted into the waste oil, and the other part was discharged to the outside of the reaction system, but since the temperature of the heat treatment was 300 ℃ or lower, it was hardly converted into dioxin. Chlorine dissolved in the waste oil can be easily released from the waste oil by conducting an operation of introducing an inert gas in the dechlorination process. Chlorine discharged during the heat treatment can be recovered by a known apparatus such as a scrubber (scrubber) used in a semiconductor process (etching process of metal film: RIE process).

In addition, the heat treatment is performed under non-oxygen conditions, such as an inert gas atmosphere, under reduced pressure, and no oil is used at this time. Preferably, the reaction is carried out at a temperature of 140 to 180 ℃ under a reduced pressure of 0.3 atm or less.

Specifically, the heat treatment includes the primary treatment and the secondary treatment described below, and both of them are preferably performed continuously. However, even if the primary treatment or the secondary treatment is carried out separately, the intended purpose of the present invention can be achieved.

[ Heat treatment for one time ]

The type of oil used for heat treatment of the coated copper wire containing chlorine-containing synthetic resin as a coating material is arbitrary, and any oil may be used as long as it can heat-treat the coated copper wire. Preferably, the heat of the oil is efficiently transmitted to the coating material, for example, the coating wire is completely immersed in the oil. The heat treatment temperature is 130 ℃ or higher, preferably 190 to 300 ℃, that is, from the decomposition temperature of the vinyl chloride resin to the dioxin synthesis temperature. Since the range of more than 300 ℃ to 325 ℃ is the temperature at which dioxin is most easily generated, it is necessary to avoid the heating temperature exceeding 300 ℃. The appropriate heating time is about 0.5 to 10 hours, and more than this time is not economically preferable, and if the heating time is too short, the intended purpose of the present invention cannot be achieved. The heat-treating one treatment is preferably carried out with stirring during the treatment.

In the heat treatment, if 15 to 80 parts by weight of an alkaline substance (e.g., lime) is present with respect to 100 parts by weight of the chlorine-containing synthetic resin, the treatment time can be shortened to about 10 minutes.

[ Heat treatment for the second time ]

The secondary treatment is carried out under non-oxygen conditions, for example, in an inert gas atmosphere, or under reduced pressure, and no oil is used at this time. Preferably, the reaction is carried out at a temperature of 130 to 300 ℃ under a reduced pressure of 0.3 atm or less, more preferably at a temperature of 140 to 180 ℃. The heating time is 0.5 to 6 hours, preferably 1 to 6 hours. Most practical is, for example, a heating condition in which the heat treatment is carried out under a non-oxygen condition at 150 ℃ for 1 hour. The non-oxygen condition is achieved by reducing the pressure using a vacuum pump, but the same effect can be obtained by the heat treatment in an inert gas (for example, nitrogen atmosphere), and it is determined as appropriate which one is used in consideration of the balance with the cost. If the heat treatment is performed under reduced pressure, the generated bubbles easily enter into the gap between the coating resin and the metal copper, and the separation of the two becomes easier.

The pressure condition for the secondary treatment may be 0.3 atm or less, and the object can be sufficiently achieved even at a pressure lower than the pressure. However, if the treatment temperature is higher than 300 ℃, chlorine not completely removed in the dechlorination treatment may cause generation of dioxin, and if the treatment temperature is too low, the carbonization reaction may not be performed well. After the completion of this step, the chlorine content in the coating resin was about 10 wt%.

Considering the fuel cost in the secondary treatment, the most suitable is about 150 ℃. In the second heat treatment, for example, a sample after the first treatment (treatment in the waste oil at 230 ℃ C. for 2 hours) is put into a metal container, and the pressure is reduced to about 0.1 atm by a vacuum pump, and the heat treatment is carried out at 150 ℃ C. for 1 hour, whereby more preferable results can be obtained than when the first treatment or the second treatment is carried out alone. It was confirmed that the sample after completion of the heat treatment did not contain dioxins.

[ basic substance ]

In the dechlorination treatment of the chlorine-containing synthetic resin, an alkaline substance is allowed to coexist, whereby an acid chloride such as hydrogen chloride generated by the dechlorination treatment can be efficiently removed. For example, the reaction with the generated hydrogen chloride can be promoted by dispersing the basic substance in the waste oil and stirring the same with blown air or the like. The presence of the alkaline substance produces excellent effects in shortening the heating time and reducing the concentration of residual chlorine. The alkali is preferably used in an amount of 15 to 80 parts by weight, more preferably 30 to 70 parts by weight, based on 100 parts by weight of the chlorine-containing synthetic resin. The basic substance may be any compound as long as it reacts with the acidic compound generated in the dechlorination treatment, and examples thereof include alkali metal hydroxides, alkali metal carbonates, alkaline earth metal hydroxides, alkaline earth metal carbonates, and the like, and specifically preferred substances include sodium carbonate, calcium oxide, calcium hydroxide, calcium carbonate, magnesium hydroxide, and the like.

[ Selective recovery of metallic copper and solid Fuel from carbide-coated copper wire ]

Since the binding force of the coated electric wire subjected to the above heat treatment at the interface between the carbonized resin and the metallic copper is weakened, the metallic copper and the carbonized resin can be easily separated by applying mechanical vibration, for example. The metallic copper and the carbonized resin are sieved by crushing and pulverizing, thereby separating the metallic copper and the carbide easily and efficiently without using a special separating device. The separation of the both is sufficiently completed by, for example, putting the heat-treated material into a barrel having an opening, rotating the barrel for several minutes, and applying vibration, whereby the metal remains in the barrel and the carbide falls downward. The fallen carbide is recovered and extruded, so that the carbide can be recycled as a heat source in the primary treatment and secondary treatment processes. The separated carbide may be used as a solid fuel in other steps, and may be used as a solid heat medium. For example, the fuel may be introduced into the furnace as a fuel used in any one of the steps of coke, lime, iron ore, sintered ore, granular iron, and scrap iron, or may be mixed with them. In addition, the solid fuel produced can also be recycled as fuel for heating waste oil or incinerators, and if so, the invention becomes a fuel-free low-cost process.

The recovered carbide is again subjected to a heat treatment in a waste oil at a temperature range of 190 to 300 ℃, preferably after being crushed to 2mm or less, and then subjected to a treatment, for example, at 230 ℃ for 10 minutes to 1 hour, and the chlorine concentration in the carbide can be reduced to about 4 wt%, preferably 1 wt% or less, and most preferably 0.3 wt% or less, with or without 60 wt% of an alkaline substance (e.g., lime) being added. So that it can be used as a fuel directly or mixed with other fuel to the extent of 10 wt% for use as a fuel (refer to fig. 3 and 4).

Example 1

A vinyl chloride resin-coated copper wire (3 mm. phi.) having the composition shown in Table 1 was treated in the following manner.

Table 1:

20L of a predetermined waste turbine oil and a waste covering wire (copper wire molded with polyvinyl chloride: about 5 kg) having the same volume were cut into a length of 50cm, put into a metal container, filled with a waste oil (mineral oil), and treated at 230 ℃ for 2 hours at a time. Assuming that the coating is a pure polyvinyl chloride resin, it contains about 56% by weight of chlorine.

After the heat treatment of the primary treatment was completed, the chlorine content in the coating was reduced to 12% by weight. Subsequently, the treated waste covered wiring was subjected to a secondary treatment at 150 ℃ for 1 hour under a non-oxygen condition. The non-oxygen condition was that a vacuum pump was used to make 0.1 atmosphere. About 4kg of the sample after completion of the above-mentioned primary treatment (treatment in oil at 230 ℃ C. for 2 hours) was charged into an iron vessel having a volume of about 20L, and the pressure was reduced to about 0.1 atm by a vacuum pump, followed by heat treatment at 150 ℃ for 1 hour. It was confirmed that the sample after the completion of the secondary treatment did not contain dioxins.

When the generated carbide was put into a barrel having an opening and vibration was applied thereto for 5 minutes, metallic copper remained in the barrel and the carbide fell from the hole of the barrel, whereby the two could be easily separated. This is an effect of easily separating copper and carbide by the secondary treatment. The amount of metallic copper recovered was about 2.5 kg. The waste coating wire is fried in the waste oil by the heat treatment, and bubbles are generated between the electric wire and the coating material to facilitate separation of the electric wire and the coating material. Further, the same test as that of the waste oil (mineral oil) was carried out using unused vegetable oil (frying oil), and it is more preferable that the same result as that of the waste oil (mineral oil) be obtained at a temperature of 130 to 300 ℃.

Example 2

10L of a predetermined waste turbine oil and about 1kg of waste covered wiring (copper wire molded with polyvinyl chloride) were put into a metal container, the waste covered wiring was completely immersed in the oil, and then heated at 230 ℃. The heating time was 1 hour to 30 hours, and the chlorine concentration in the waste covered wiring heated in the waste oil was measured at predetermined time intervals by a fluorescent X-ray analysis method. As a result, it was found that the residual chlorine was reduced to about 12% by heating for 10 hours or more. Chlorine in the waste coating wiring is dissolved in waste oil as hydrogen chloride or released into the atmosphere. Since the heating temperature is low at 300 ℃ or lower, dioxin is not generated. As a result of measurement of dioxin, the concentration of total dioxins (PCDDs + PCDFs + coplanar PCBs) was 0.14ng/g, and the measured amount (equivalent toxicity) was 0.045 ng-TEQ/g. The measured value showing the relationship between the chlorine concentration in the coating resin and the heating time is shown in fig. 2. The measurement results of this example are shown as [ A measurement ] in the figure.

Example 3

In example 2, when the heat treatment was performed, lime (Ca (OH)) was added to waste oil (turbine oil) in an amount of about 50 parts by mass per 100 parts by weight of polyvinyl chloride₂) Heating is performed. The lime neutralizes the hydrogen chloride generated from the polyvinyl chloride by the heat treatment, preventing the hydrogen chloride from being released to the atmosphere and dissolved in the waste oil. By adding lime, the residual chlorine was drastically reduced to about 12% in a heating time of about 1 hour or less, particularly about 10 minutes (FIG. 2 [ B measurement ]]). Chlorine is deposited as calcium chloride on the bottom of the container, and therefore can be recovered as solid calcium chloride. It is clearly understood that the dechlorination effect can be further improved by adding the alkaline substance in this manner.

Example 4

About 1kg of waste covering wiring (copper wire molded with polyvinyl chloride) was charged into a metal container, and the container was maintained at 150 ℃ for 1 hour under a reduced pressure of 0.1 atm. Chlorine in the waste coating wiring is released as hydrogen chloride in the container. The hydrogen chloride generation is increased by treatment under reduced pressure. By performing the heat treatment in a reduced pressure state, the copper wire and the clad material can be more easily separated.

Example 5

As shown in FIG. 3, the carbide recovered in example 1 was pulverized to 5mm or less, and heat-treated again in a waste oil at 230 ℃ for 10 to 60 minutes. As shown in fig. 4, the chlorine content in the carbide was reduced from 1 wt% or less to a content of less than 0.3 wt% with or without the addition of 60 wt% of an alkaline substance (e.g., lime). By adding this third stage of treatment, the chlorine content in the carbide is further reduced, and a carbon fuel containing a small amount of chlorine, which can be used as a fuel as it is, is obtained.

Possibility of industrial utilization

The invention relates to a method for recovering metallic copper from wastes containing chlorine-containing synthetic resin and metallic copper, which is an invention for treating wastes mixed with the chlorine-containing synthetic resin and the metallic copper to recover useful substances. According to the present invention, if metallic copper can be recovered as a resource from electric wires coated with chlorine-containing synthetic resin, which are discarded in large quantities in japan at present, the waste can be effectively utilized, and the cost required for discarding is not required. In addition, the present invention is applicable not only to the treatment of waste coated wiring but also to waste containing chlorine-containing synthetic resin or other types of synthetic resin mixed with metallic copper. The present invention provides a novel technique capable of preventing environmental pollution and adverse effects on human health in waste treatment. In addition, the present invention is also a method of effectively utilizing various waste oils, which is also an advantage. The chlorine content is further reduced by further heating the coating material in oil, and the coating material can be recovered as a carbon-based fuel.

Claims (4)

1. A method for recovering metallic copper from waste coated with copper wire is characterized in that,

a waste material of a copper wire coated with a chlorine-containing synthetic resin as a coating material is subjected to a heat treatment in an oil at 130 to 300 ℃, then the coating material is carbonized and the chlorine content is reduced by performing a heat treatment at 130 to 300 ℃ in a nitrogen atmosphere or under a reduced pressure of 0.3 atmosphere or less without using an oil, and then the coating material and the copper wire are separated to recover the copper wire.

2. The method for recovering metallic copper from waste covering copper wires according to claim 1,

the heat treatment in the oil is performed in the coexistence of an alkaline substance.

3. The method for recovering metallic copper from waste covering copper wires according to claim 1,

the clad material after the copper wire recovery is further subjected to a heat treatment in oil to further reduce the chlorine content, and is recovered as a carbon-based fuel.

4. The method for recovering metallic copper from waste covering copper wires according to claim 1,

the chlorine-containing synthetic resin is polyvinyl chloride, polyvinylidene chloride, vinyl chloride copolymer, chlorinated resin, or a mixture of the chlorine-containing synthetic resin and other resins.