JPS5829206B2 - Method for selecting and recovering halogenated vinyl insulation from mixed insulated wire scrap - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for recovering metal and insulation in usable form from mixed insulated wire scrap.

More particularly, the present invention relates to a method for selectively recovering specific insulating materials from mixed insulated wire scrap comprised of several insulators and metals.

Although there are various common scrap recovery techniques for removing insulation from mixed insulated wire scrap, the following are the few exceptions:

(1) Mechanical separation by grinding or cutting, (2)
Either burn the insulated wire scrap and incinerate the insulation.
Or tear the insulation from insulated wire scraps,
or (3) chemical separation of the insulation from insulated wire scrap, i.e., traditionally used for the recovery of metal conductor wire. technology.

Examples of the aforementioned techniques include U.S. Pat. It shows a method that combines mechanical and thermal techniques to remove insulation by cutting away the cooled insulation with a blade.

US Pat. No. 3,635,454 provides one example of the aforementioned high temperature processing technique.

The method described in U.S. Pat. No. 3,635,454 depolymerizes the organic insulation in a heated stream of nitrogen gas, thereby removing the insulation from the wire.

In U.S. Pat. No. 3,666,691, Spiller (
5 Piller) presents a method different from the previously described techniques.

The technique shown in Spiller contacts a scrap mixture containing polyvinyl chloride resin with both the liquid and gas phases of a solvent in an autoclave, and then
Polyvinyl chloride resin is recovered from mixed insulated wire scrap by evaporating the solvent and recovering the polyvinyl chloride insulation from the solvent.

In U.S. Pat. No. 3,624,009, polyvinyl chloride A method for recovering resin and material is shown by Sussman.

As described above, in the conventional technology, either the insulator is destroyed and only the metal conductor is recovered, or an expensive and time-consuming processing method is required, which varies depending on the type of insulator coated on the conductor. It was.

Additionally, while these methods are effective in certain cases, they are unsuitable for continuous, selective recovery of large amounts of insulation and metal from insulated wire scrap containing mixtures of insulation. This includes many problems as described below.

(1) Chemical changes in the insulator that make it impossible to reuse the insulator as wire insulation; (2) Contamination of the recovered metal with chemicals that are harmful to standard metal refining methods; and (3) the aforementioned techniques. (4) the production of pollutants such as dust smoke and hydrogen chloride that must be removed;

As mentioned above, there is a need for a method for recovering insulators from insulated wire scraps that improves the drawbacks of the conventional methods.
Continuous polyvinyl halide insulation from mixed insulated wire scrap containing other organic insulators without adversely affecting the insulation ability of the polyvinyl halide insulation,
A method of selective recovery is needed.

The present invention provides a method for continuously, selectively recovering polyvinyl halide insulation from mixed insulated wire scrap containing at least one other insulation material by the following steps.

(a) The polyvinyl halide insulation is dissolved by the solvent from the mixed insulated wire scrap at a temperature where the solvent is a special solvent for the polyvinyl halide insulation and does not affect other insulations in the mixed insulated wire scrap. process.

(b) separating the unmelted portion of the insulated wire scrap from the melted polyvinyl halide insulation;

and (c) recovering the dissolved polyvinyl halide insulation from the solvent in a dry state suitable for reuse.

More specifically, the present invention is comprised of the following steps.

(a) Preparing a countercurrent extractor.

(b) feeding the mixed insulated wire scrap into a countercurrent extractor, where the solvent is a special solvent for polyvinyl halide insulation, and at which temperature the solvent coexists in the mixed insulated wire scrap; supplying a solvent to a countercurrent extractor at a temperature such that it has no substantial side-to-side solvent effect on the insulators, followed by water.

(c) moving the mixed insulated wire scrap through a countercurrent extractor while contacting it with a countercurrent stream of solvent maintained at a temperature that dissolves the polyvinyl halide insulation.

(d) discharging the molten polyvinyl halide insulation from the countercurrent extractor while leaving the undissolved portion of the mixed insulation wire scrap in the countercurrent extractor;

(e) Regenerating the dissolved polyvinyl halide insulation from solution in a form suitable for extrudates for electrical wires.

(f) Washing the undissolved parts with water to remove residual solvent from the undissolved parts.

and (g) recovering the solvent from steps (e) and (f) for subsequent reuse in step (b).

The dissolution rate of the vinyl halide polymer is controlled by controlling the flow rate and temperature of the organic solvent, and there is no need for stirring.

A force is applied to move the mixed insulated wire scrap against the direction of the solvent flow, but only to transfer the insulated wire scrap from the scrap inlet of the countercurrent extractor to the solids outlet of the countercurrent extractor. be.

Also, a force is applied to the solvent through the countercurrent extractor, and the rate at which the solvent passes through the countercurrent extractor controls the rate at which the polyvinyl halide insulation dissolves from the mixed insulated wire scrap.

The present invention has been explained using N-methylpyrrolidone as an example of a solvent, but the solvent is not limited to N-methylpyrrolidone, and under the conditions that it becomes a special solvent for polyvinyl halide insulators. , N-methylpyrrole may also be used.

The term "polyvinyl chloride insulation" as used herein refers to polymers containing one or more additives normally present in polyvinyl chloride insulation, such as pigments, fillers, plasticizers, antioxidant pharmaceuticals, etc. means a polymeric mixture of polyvinyl chloride or a copolymer of polyvinyl chloride contained or suspended within a matrix.

Hereinafter, the present invention will be explained in detail using the drawings.

The apparatus shown in Figure 1 now illustrates a method for selectively melting and recovering polyvinyl halide insulation from a mixture containing many different types of electrical insulation and metal conductor scrap. .

Ideally, the raw materials used in embodiments of the invention include shredded metal conductors such as aluminum or aluminum alloys, or copper or copper alloys, and similar metal conductors, compounds of polyvinyl chloride, and ethylene. It consists of a mixture of wire scrap consisting of propylene rubber copolymers, cross-linked polyethylene, and other polymers such as acrylic varnishes, which are suitably used as wire insulation.

Although the successful implementation of the invention does not depend, from a technical point of view, on the relative concentrations of the aforementioned materials in the insulated wire scrap mixture, if the implementation of the invention is to be economically successful, these depends on the relative concentrations of the materials.

The invention can also be practiced without first treating the scrap mixture to remove moisture contained in the insulated wire scrap.

Also, it is not necessary to carry out the extraction process of the invention in a closed extractor under an inert gas.

The appropriately cut mixed insulated wire scraps are sent to the extractor 12.
and is contacted with a counterflowing solvent at a temperature that causes the solvent to dissolve the polyhalogenated vinyl insulation present in the scrap, particularly vinyl halide polymers, PVC, and copolymers of PVC.

In embodiments of the invention, the solvent flowed in a direction opposite to the direction of transport of the shredded scrap is heated to a temperature of about 76.7°C to about 104.4°C before being pumped into the extractor 12.
(about 170'F to about 220'F), the solvent contacts the shredded mixed insulated wire scrap in the extractor 12 and dissolves the polyvinyl halide insulation contained therein. do.

The insoluble solids remaining after the contact of the cut insulated wire scrap with the preheated solvent are transferred to the cleaning chamber 13, where the insoluble solids are appropriately fed to the cleaning chamber 13 and combined with backflowing water (not shown). Any residual organic solvent that adheres to the insoluble solids upon contact is removed.

The insoluble solids (polypropylene, polyethylene, copper, aluminum, etc.) are then transferred into liquid separator 14 where water and residual solvent are separated from the insoluble solids.

A stream of solvent water (5-20% solvent) from wash chamber 13 is pumped into water tower feed tank 21.

The insoluble solids discharged from the wash chamber 13 contain high percentages of metals, polypropylene, polyethylene, cross-linked polyethylene, and materials other than the polyvinyl halide insulation that was present in the original scrap of insulated wire scrap.

The insoluble solids discharged from the wash chamber 13 are an ideal feed for a harmonized process, or alternatively, if a powdered feed is desired for a harmonic furnace, those insoluble solids have been heated beforehand. After undergoing decomposition treatment, it will be introduced into a metal recovery furnace.

Polyhalogenated vinyl insulation solutions, such as those containing from 0.01 to about 2 s% of polyhalogenated vinyl insulation, are prepared as follows to remove any small particulate residual solids discharged from the extractor 12. It is filtered through a special filter system 15.

First, large particles are removed by first filtration with a coarse structure filter, and smaller particles are removed by filtering with a coarse structure filter.
It is removed with a 5 micron fine filter.

The material recovered by the filter system 15 is then transferred directly to a metal recovery furnace or, if a significant amount of polyvinyl halide insulation is present therein.
Either it is recycled to the extractor 12.

The polyvinyl halide insulation solution is then pumped into bulk supply tank 16 which supplies the polyvinyl halide insulation solution to preheater 17 .

One important aspect of the present invention is the need to maintain a homogeneous solution of polyvinyl halide insulation during recovery of the polyvinyl halide insulation from solution.

This continuously circulates the recovered polyvinyl halide insulation solution in a circuit through tank heater 30 and back to bulk supply tank 16 via pump 29, thereby creating a homogeneous distribution of the vinyl halide insulation. This is accomplished by maintaining the solution and, if the solution is N-methylpyrrole, simultaneously raising the temperature of the solution to about 100<0>F.

The polyvinyl halide insulation solution is then passed through evaporator 1.
8.

When the polyvinyl halide insulation solution is introduced into the evaporator 18, it passes through a preheater 17, where the temperature of the solution is approximately 48.5% if the solvent used is N-methylpyrrole. It can be raised to 9°C (approximately 120'F).

Ideally, the evaporation of the solvent and recovery of the resulting polyvinyl halide insulation should occur at about 0.2 to 0.9 atmospheres and at about 900F.
~300'F) in a thin film evaporator 18.

The temperature and pressure used to cause evaporation of the solvent from the polyvinyl halide insulation solution is the temperature and pressure used to dissolve the oxidizing agent and the polyvinyl halide insulation within the polyhalide insulation. It depends on the solvent used, where the higher the concentration of oxidation inhibitor in the insulation, the higher the temperature of the solvent.

The recovered polyvinyl halide insulation (typically 99% solids) is recovered from the evaporator 18 in a substantially dry state through a product outlet pump 24.

A slop tank 25 is provided for use during operation and for flushing the evaporator 18.

The solvent vapor produced in evaporator 18 and typically containing 1% water is transferred as a liquid via pump 28 to solvent base supply tank 20 and pure solvent storage tank 11.

Generally, the flow is split 50:50 between the two tanks.

Any moisture picked up from the scrap metal-insulation mixture by the solvent is removed within the solvent base 19.

1 baseboard volume of solvent stream is mixed with a superheated stream from water tower 22 (about 4.1 to about 7.1 baseboard volumes) to provide a feed for solvent base 19 containing about 3.9% water. Becomes a solvent.

This solvent is pressure distilled to produce a solvent stream containing about 0.32% water and fed to extractor 12.
It is stored in a pure solvent storage tank 11.

The solvent water wash stream from the wash chamber 13 containing about 90 t) is mixed in the water tower feed tank 21 with the overhead from the solvent base 19 containing about 11.7% water, resulting in about 84 t) Resulting in a water tower feed component of .5% water.

Water storage tower 22 is operated at 1 atmosphere and produces water containing approximately 0.043φ solvent, which is stored in pure water storage tank 23 for reuse during the process after distillation.

Overhead from water tower 22 is stored in solvent base feed tank 20 for subsequent redistillation.

Now, the extraction part of the method according to the invention consists in that cut mixed insulated wire scraps from steel metal, polyvinyl chloride, polyethylene, cross-linked polyethylene, ethylene-propylene rubber, polypropylene, Teflon and nylon are placed in an extractor 12. is continuously supplied in a fixed amount to the liquid discharge port, and moves in a predetermined manner from the vicinity of the solution discharge port to the solid discharge port,
During this time, the solvent is continuously contacted with counterflowing solvent at a temperature that causes the solvent to dissolve only the PVC insulation.

Examples of the solvent used in the present invention include N-methylpyrrole, N-methylpyrrolidone, and mixtures thereof.

For N-methylpyrrolidone, about 76.7°C to about 1
from about 170'F to about 220°F, preferably from about 195'F to about 104.4°C.
Preferred as a selective solvent for polyvinyl chloride insulation at a temperature of about 220"F), in the case of N-methylpyrrole,
32°2°C to approx. 48.9°C (approximately 90″F' to approx. 120°C
'F) is preferred.

The concentration of the polyvinyl chloride insulation solution is controlled by adjusting the temperature of the solvent, the flow rate of the solvent and the flow rate of the insulation wire scrap.

An effective extraction process of the present invention is carried out at 1 atmosphere and does not need to be carried out under a special atmospheric pressure.

Desirably, the extractor 12 is isolated from outside air;
The reason for this is economic rather than technical to reduce solvent loss.

The solvent discharged from the extractor 12 has a concentration of dissolved polyvinyl chloride insulation of about 8 to about 17 centimeters for all solvents, although the desired concentrations for different solvents are different.

The following examples are intended to further illustrate the invention:
It is not necessarily intended to be limiting except as described in the claims.

All parts and percentages are by weight unless otherwise noted.

Example 1 Shredded insulated wire scrap consisting of metallic steel, polyvinyl chloride insulation, polyethylene, cross-linked polyethylene, nylon, Teflon and polypropylene was collected in a Gifford Wood furnace operating at 1 atm.
Wood) was introduced into a countercurrent extractor.

The extractor was adjusted to move the mixed insulated wire scrap from the scrap inlet toward the insoluble solids outlet at a constant rate.

The scrap was continuously contacted with heated countercurrent N-methylpyrrolidone as it moved through the extractor.

The heated N-methylpyrrolidone is introduced into the extractor through the solvent inlet located near the insoluble solids outlet, and the flow rate is 14.61% ± 1 by weight as measured at the solvent outlet.
Adjusted to maintain a solution of PVC insulation.

PVC insulation solution is suitable for coarse filtration (C
uno) mechanism filter and a series of 25 micron polyethylene cartridge filters for fine filtration.

The filtered PVC insulation solution is then pumped into a thin film evaporator at approximately 48.9°C (48.9°C).
Dry PVC insulation and N
-Methylpyrrolidone was recovered.

The N-methylpyrrolidone, as well as the aqueous solution from the insoluble solids, was recycled by standard distillation methods for reuse in the extractor.

The recovered PVC insulation is then packaged for subsequent use in an extrudate process for insulated wire and cable, and the insoluble solids are used as feedstock in a combustion refining process to regenerate copper. Packaged for subsequent use.

The same method and equipment were used in Examples 2-4, but the operating conditions varied depending on the solvent used, as seen by reference to Table I.

Examples 2-4 The method of Example 1 was similar except that some PVC insulation special solvents and PVC insulation non-solvents were used.

Working (operating) temperatures varied depending on the solvent used.

Table 1 illustrates the effect of the various solvents used in Examples 1-4 on insulation materials other than polyvinyl chloride insulation present in the mixed insulated wire scrap processed by the process of the present invention.

From Table 1, it is clear that for Nakamoto operating conditions the solvent and process are selective for polyvinyl chloride insulation and polyvinyl chloride copolymer insulation.

Example 5 PVC insulation recovered from the mixed insulated wire scrap described in Example 1 was coated as insulation onto Al0AWG copper wire using standard industry techniques of extruding PVC insulation. Ta.

The material used in this extrusion process is such that it gives the material a uniform particle size and so that a uniform feed rate of recovered dry PVC insulation to the extruder can be achieved. It had been previously processed through a standard granulation process for the sole purpose of improving its solid flow characteristics.

The recovered polyvinyl chloride insulation had not undergone any additional processing, including the addition of new plasticizers or stabilizers, before or during extrusion.

A black pigment was added to the extruder to improve the color of the final extrudate.

The face shall have a minimum acceptable tensile strength and
atories) represents the physical properties of the extracted and recovered material compared to the ultimate elongation conditions for the J-approved PVC jacket compound.

The data in Table I show that plasticizers and fillers are not removed from polyvinyl chloride insulation by the extraction process of the present invention.

As mentioned above, the present invention has been explained by one embodiment, and various modifications and changes can be made without departing from the spirit and scope of the claims. It is intended that the present invention include all modifications and variations of the present invention without departing from the scope of the claims.

[Brief explanation of the drawing]

FIG. 1 is a diagrammatic illustration of the steps comprising the method of the invention. Explanation of symbols representing main parts of the drawings: 12...Extractor, 13...Cleaning chamber, 18...Evaporator.

Claims (1)

[Claims] 1. Continuous and selected polyvinyl vinyl insulation in reusable condition with additives from mixed insulated wire scrap containing at least one other insulation material. (a) N-methylpyrrolidone or N-methylpyrrol, which are special solvents for polyvinyl halide insulation, respectively, without affecting other insulation materials of mixed insulated wire scrap; about 7
6.70C to approx. 104.4°G (approx. 170°F to approx. 22
00F) and approximately 32.2°C to approximately 48.9°C (approximately 9
00F to about 120'F);
(b) at least one extractor 12 and at least one
The extractor 1 of the countercurrent extraction device is equipped with a washing chamber 13 and a washing chamber 13.
2, a step of supplying mixed insulated wire scraps and the solvent, and supplying water to the washing chamber 13; (c) while moving the mixed insulated wire scraps in the countercurrent extractor 12; (d) selectively dissolving polyvinyl halide insulation from mixed insulated wire scrap in said solvent by contacting with a countercurrent flow of said solvent maintained at a temperature range; (e) extracting the undissolved portion of the mixed insulation scrap; (e) extracting the undissolved portion of the mixed insulation scrap; The washing chamber 13 is moved from the vessel 12 to the washing chamber 13.
and (f) removing residual solvent adhering to the undissolved portions by contacting with water supplied to and flowing back into the evaporator 18 without thermally decomposing the polyvinyl halide insulation material. evaporating the solvent from the solution to recover polyvinyl halide insulation in a dry state suitable for reuse. 2. The method described in claim 1, wherein the mixed insulated wire scrap is made of polyethylene, crosslinked polyethylene, nylon, Teflon, polyvinyl chloride, polyvinyl chloride copolymer, chlorinated polyethylene, ethylene-propylene rubber. and a mixture of copper and aluminum metals combined with an insulating material such as polypropylene. 3. The method according to claim 1, wherein the polyvinyl halide insulating material is a polyvinyl chloride insulating material,
A method characterized in that the material is selected from the group consisting of polyvinyl chloride copolymer insulation materials and mixtures thereof.