JP6757516B2 - How to dispose of copper-containing scrap - Google Patents

Description

The present invention relates to a field in which copper-containing scrap containing a valuable metal such as gold or silver is processed to recycle the valuable metal.

Currently, from the viewpoint of resource depletion, recycling of various things is progressing. In particular, the recycling of metals that are consumed in large quantities has been carried out for some time. For example, copper is widely used in the world, and since the amount of copper-containing scrap, which is scrap containing copper, is large, recycling has been actively carried out.

However, among materials using copper, copper wiring materials such as electric cables contain a large amount of organic substances that are coating materials in addition to copper, but if they are tried to be melted at high temperatures as they are, harmful gas may be generated. There is a problem that the temperature becomes excessively high and the melting furnace is damaged. For this reason, in developing countries where labor costs are low, the coating is peeled off by hand to separate only the core copper wire, which is then melted and processed, but in developed countries where labor costs are high, the cost is high. In terms of aspects, it is not profitable, and there are problems such as long processing time.

In addition, precious metals such as gold and silver are used for electronic parts and the like. Since these precious metals are expensive, they can often make a profit even if the recycling cost is a little high, and recycling is progressing in Japan as well.
However, recycling only one metal, such as copper or gold, is inefficient, and in particular, relatively inexpensive metals such as copper are often unprofitable at present.
In the case of recycling as described above, the processing cost becomes a big problem, but there are various technologies depending on what is recycled and the recycling method, and many technical problems remain.

For example, Patent Document 1 states, "(1) The shredding process that is performed by nugget processing is unnecessary, the pretreatment process is simplified, and the processing can be performed in a short time, so that a large amount of processing can be performed, and copper from the coated electric wire Recycling cost can be reduced because almost 100% of the material can be recovered. (2) Although a copper and coating recycling system has already been completed by cutting with a nugget machine, recycling is difficult due to economic factors. By targeting automobile harnesses, etc., which are disposed of in large quantities such as thin wires and miscellaneous wires that have not been resolved in the above, it will be useful for further effective use of resources and environmental conservation. " "A continuous drying device that separates and recovers the covering material and copper wire by thermally decomposing the coated wire using an electric heater and a heating means by microwave irradiation in a no-to low oxygen atmosphere, and this continuous drying device generates A "coated wire recycling system" is disclosed, which comprises a catalyst gas purifying device for purifying the decomposed gas and a hydrogen chloride absorbing tower for removing hydrogen chloride generated by thermal decomposition of the coated electric wire. ..

However, the system that thermally decomposes the coated electric wire described in Patent Document 1 in a low oxygen atmosphere by using an electric heater and a heating means by microwave irradiation requires too much initial equipment cost and also in a low oxygen atmosphere. It costs a lot of running cost to keep it compared to the case of processing in the air atmosphere.
Furthermore, if it is thermally decomposed by an electric heater, electricity that has a high unit cost is used, so that it cannot be processed inexpensively. In addition, thermal decomposition by heating by microwave irradiation requires equipment, and industrial implementation is difficult when a large amount of coated electric wire or scrap is to be processed.

Further, Patent Document 2 states, "By heating precious metal scrap in a first combustion furnace at a low air ratio, it is thermally decomposed and gasified at a low temperature, and a gasified volume-reduced product which is a residue after gasification. By further combusting in a second combustion furnace, it is possible to easily recycle precious metals by using incineration ash containing precious metals as an intermediate raw material in a copper smelter, and it is possible to generate dioxin. Recovery from electronic parts containing valuable metals such as copper, gold, and platinum for the purpose of "providing a method and equipment for treating precious metal scrap that can reliably prevent the danger of ignition of incineration ash." The precious metal scrap is thermally decomposed and gasified by heating it in the first combustion furnace while preventing the intrusion of free air, and the carbonaceous-based gasification volume-reduced product, which is the residue after gasification, is the first. It is incinerated in a second combustion furnace connected to one combustion furnace, and the incineration ash is cooled to a predetermined temperature in a water tank as a valuable metal-containing slag, and then continuously recovered by a conveyor and gasified flammable. A method for treating precious metal scrap, which comprises completely combusting the thermally decomposed gas of the above in a third combustion furnace ”is disclosed.

However, by heating the precious metal scrap recovered from electronic parts containing valuable metals such as copper, gold, and platinum in the first combustion furnace while preventing the intrusion of free air, which is described in Patent Document 2. The carbonaceous-based gasification volume-reduced material, which is the residue after thermal decomposition and gasification, is incinerated in the second combustion furnace connected to the first combustion furnace, and the incineration ash is valuable. There are three furnaces in a system that cools the metal-containing slag to a predetermined temperature in a water tank and then continuously recovers it with a conveyor and completely burns the gasified flammable thermal decomposition gas in a third combustion furnace. In addition to the high equipment cost and running cost, continuous intermediary between furnaces is a waste that causes equipment troubles and changes in operating conditions (the operating conditions are large due to the collected electronic parts). It is difficult to operate with (different).

International Publication WO2014 / 020958 Japanese Unexamined Patent Publication No. 2015-148397

The present invention has been proposed in view of such circumstances, and is obtained from a roasted product obtained after roasting the scrap in a method for recycling copper-containing scrap containing copper, gold, and silver as valuable metals. It is an object of the present invention to provide a method for recycling copper-containing scrap, which comprises recovering valuable metals by sorting them.

As a result of diligent studies to solve the above-mentioned problems, the present inventors have roasted scrap in a method for recycling copper-containing scrap containing copper and gold or silver (hereinafter, simply referred to as scrap). Later, they found that valuable metals could be recovered from scrap roasted products by a method of selecting valuable metals from the roasted products, and came to the present invention. That is, the present invention provides the following.

In the first invention of the present invention, a roasted product obtained by roasting copper and copper-containing scrap containing either or both of gold and silver as valuable metals is used as an intermediate raw material, and the intermediate raw material is used as a primary raw material. After obtaining the primary sorted product and the primary sorted roasted product that have been sorted and separated, the primary sorted roasted product is subjected to the secondary sorting to recover the valuable metal contained therein, and the primary sorted product is used. This is a method for treating copper-containing scrap, which comprises recovering valuable metals by using either (1) or (2) or both of the following.
(Record)
(1) Heat and melt at 1100 ° C. or higher using an electric furnace, separate into a metal component and a slag component, and recover valuable metal as a metal component.
(2) The product is crushed and used for the primary sorting to separate the primary sorted product and the primary sorted roasted product, and the primary sorted product is subjected to the above (1) to recover the valuable metal of the metal component. , or after repeatedly performing the processing of (2), said implementation to recover valuable metals through the (1), to recover the valuable metals contained the primary sorting already roasted product was screened secondary.

Further, in the second invention of the present invention, in the primary sorting in the first invention, the intermediate raw material is sieved by using a sieving method using a sieve having a mesh size of 2.0 mm or less to obtain a sieved product. This is a method for treating copper-containing scrap, which comprises sorting a sieved product as a primary sorted product and a screened product as a primary sorted roasted product.

Further, the third invention of the present invention is a method for treating copper-containing scrap, characterized in that the primary sorting in the first invention is a specific gravity sorting method.

Further, the fourth invention of the present invention is a method for treating copper-containing scrap, characterized in that the secondary sorting in the first to third inventions is a method of sorting using electromagnetic induction.

A fifth invention of the present invention is a method for treating copper-containing scrap, characterized in that the intermediate raw material in the first invention contains a crushed primary sorted product obtained by crushing the primary sorted product.

According to the present invention, in a method for recycling copper-containing scrap containing copper, gold, and silver as valuable metals, the scrap is roasted, and then the obtained roasted product is selected to recover the valuable metal. Valuable metals can be recovered from waste, processing costs can be kept low, resources can be reused, and therefore the degree of industrial contribution is very high.

It is a process flow diagram of the method of recycling a valuable metal from a general copper-containing scrap. It is a process flow diagram in the case where the selection of a valuable metal in the method of recycling the valuable metal from the copper-containing scrap according to the present invention is divided into a primary selection and a secondary selection.

Hereinafter, a specific embodiment of the present invention (hereinafter, referred to as “the present embodiment”) will be described in detail. The present invention is not limited to the following embodiments, and various modifications can be made without changing the gist of the present invention.

The present invention is characterized in that, in a method for recycling valuable metals from copper-containing scraps, valuable metals are recovered by roasting the scraps, using the obtained roasted material as an intermediate raw material, and selecting the raw materials. It is a thing.
The types of copper, which is a valuable metal as a raw material, and copper-containing scrap containing gold and silver are not particularly limited. That is, the copper content contained in the scrap is sorted, recovered, refined at a copper smelter, and recovered as copper. Furthermore, other valuable metals such as gold and silver contained therein are selected and recovered. In this way, not only the copper content but also other valuable metals can be recovered from the copper-containing scrap, so that further cost merit can be achieved.
Hereinafter, each step will be described in detail.

<Roasting process>
The method of roasting copper-containing scrap for producing an intermediate raw material is not particularly limited.
It can be used in rotary kilns and batch roasting furnaces. A rotary kiln is particularly preferable because it can be heated uniformly while mixing scrap. The heating method is not particularly limited, and electricity, coke, pulverized coal, heavy oil, or the like may be used. In particular, pulverized coal and heavy oil are preferable because they are inexpensive.

The roasting temperature is preferably 300 ° C. or higher and 800 ° C. or lower when a relatively large amount of organic matter is contained such as coated copper wire. Below 300 ° C, organic matter is difficult to decompose and burn, and there is a high possibility that it will remain unburned. If the temperature exceeds 800 ° C., there is no problem in roasting, but the temperature is higher than necessary, which increases the fuel cost and is not preferable.

Further, when the copper-containing scrap contains cadmium, zinc, etc. in addition to valuable metals such as copper, gold, and silver, and it is desired to remove these elements, it is preferable to roast at a high temperature exceeding 800 ° C. For example, when heated to a temperature exceeding 800 ° C., cadmium and zinc contained in the roasted product can be volatilized and separated, and the content in the roasted product can be reduced.
As described above, the range of the roasting temperature is not particularly limited, but the roasting treatment is performed by appropriately selecting it according to the type of copper-containing scrap as a raw material.

When a rotary kiln is used for roasting, the rotation speed of the rotary kiln is approximately several rpm, although it largely depends on the scale and processing capacity of the apparatus. If the rotation speed is too slow, it is difficult to roast the scrap uniformly, and if the rotation speed is too high, the scrap will fly up and be discharged from the kiln before it can be sufficiently roasted, which is not preferable.
When the copper-containing scrap is large, it is preferable to crush it into a size that is easy to handle. Further, it may be pulverized to a size in consideration of the sorting process which is a subsequent process.

<Sorting process>
In contrast to the conventional recycling method shown in FIG. 1, the present invention is carried out in the process flow as shown in FIG. 2, and is characterized in that selection is performed a plurality of times using a roasted product obtained by roasting scrap as an intermediate raw material. To do.
When sorting, the number of times of sorting and the sorting method may be selected according to the size and distribution of valuable metals in the roasted food, but relatively large lumps of valuable metals and scrap containing valuable metals are sorted at the beginning. It is preferable to recover the scrap containing valuable metals and valuable metals in a small and difficult-to-recover mass by the subsequent sorting because it can be efficiently recovered.

The sorting conditions are as follows: First, as the primary sorting condition, sieving is performed using a sieving method using a sieve having a mesh size of 2.0 mm or less, preferably 1.5 mm or less, and the valuable metals and precious metals constituting the roasted product are selected. It is cheap, efficient and preferable to sort a relatively large sieved product as a primary sorting product among the scraps contained. The lower limit of the opening is that it is necessary to have an opening that does not cause clogging when sieving, and in the case of sieving with a sieving with a small opening, it is about several tens of μm contained in the roasted product. Since roasted foods containing finely sized valuable metals (especially Au etc.) are excluded and the recovery rate of the valuable metals is lowered, the lower limit of the sieve is not set.

Further, specific gravity sorting (also referred to as specific gravity beneficiation) may be used as the primary sorting.
For the sorting, wet sorting using a heavy liquid or water adjusted to a specific specific gravity can be used, or dry sorting utilizing an air flow in the air may be used.
That is, in the wet sorting, when the roasted product is sorted with water or the like, the ash-like product floats or floats in water, while the metal component is heavy and settles to become a sediment, which is preferable in terms of sorting efficiency.
In the dry sorting, in the case of sorting using an air flow, oxides such as ash have a small specific gravity and can be easily blown far away, while metal components are heavy and do not fly so much and are easily separated, which is preferable.

Various known devices and methods are known for wet sorting, but the specific gravity of the heavy liquid is appropriately adjusted according to the specific gravity of the metal component and the ash-like substance contained in the target roasted product. You just have to adjust.
Specifically, the specific gravity of the metal component is 5 to 10 g / cm ³ or more, while the specific gravity of the typical coal ash or silicon oxide of fly ash is about 2 to ³ g / cm ^3. , The specific gravity of the heavy liquid can be effectively separated by adjusting it to be larger than that of the ash and smaller than that of the metal component.
Further, in the case of sorting using an air flow, the flow velocity of the air flow may be appropriately selected by adjusting it according to the properties of the target metal component and the ash-like substance.

Next, a valuable metal or a valuable metal of the primary sorted roasted product of the sieving product obtained by sieving with a sieve having a mesh size of 2.0 mm or less or 1.5 mm or less and removing the primary sorted product as a sieve product. The scrap containing the above is subjected to secondary sorting by sorting using electromagnetic induction.
The primary sorted roasted product contains very small valuable metals because scrap is crushed, thermal stress and mechanical crushing progress during roasting, and fine valuable metals are inevitably generated. Such fine valuable metals are, for example, several tens of μm or less, and even finer ones are contained. Therefore, sorting using electromagnetic induction is relatively inexpensive, has a high processing speed, and is a small metal. It is preferable as a sorting method in the secondary sorting because it is excellent in recovering. The "superficial product" refers to what remains on the sieve, and the "sub-sieve product" refers to the product that has been sieved and collected under the sieve.

In this way, the sorting is preferably performed in two stages.
Specifically, in the first-stage primary sorting, separation is performed by particle size using a sieve or the like, and then the valuable metal contained in the sieve product of the primary sorting is used as the second-stage secondary sorting. It can be efficiently separated and recovered by recovering using a method such as electromagnetic induction (magnetic selection).

Further, since the relatively large primary selection obtained by the primary selection is composed of a so-called metal component containing ash composed of oxides, the metal component is heated and melted at 1100 ° C. or higher using an electric furnace. And separated into slag components, and the metal components were recovered.
Alternatively, a part of the primary sorting product forms a crushed primary sorting product crushed to an appropriate size and is used as an intermediate raw material for the sorting process, and is selected again for the primary sorting and the secondary sorting. By repeating the process, the amount of valuable metal recovered can be increased. The crushed primary sorted product may be mixed with the roasted product and used as an intermediate raw material.

Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Examples, but the present invention is not limited to the following Examples.

As raw materials, samples A to F, which are obtained by finely crushing scraps of electronic materials including lead frames, semiconductor elements, coated copper wiring, etc. with a crusher and mixing them uniformly, and dividing them into 6 pieces of 10.0 kg each, are used. did.
Then, for each sample, each lot was roasted equally in a heavy oil combustion atmosphere (N ₂ : CO ₂ : H ₂ O = 75: 15: 10) at 700 ° C. for 3 hours using a small rotary kiln. A set of roasted products A to F was obtained.

The obtained roasted product A was sieved using a sieve having a mesh size of 1.5 mm as a primary selection, and the sieve product remaining on the sieve was collected as a primary selection product. Further, the primary sorted roasted product of the sieved product collected under the sieve was used as a secondary sorting to recover valuable metals by electromagnetic induction using an electromagnetic induction sorter.
Next, the recovered products of the primary sorting and the secondary sorting were chemically analyzed using a known method to determine the quality, and the amount of metal as the recovered valuable metal was calculated.
As shown in Table 1, 403 g of copper, 0.5 g of gold, and 0.3 g of silver could be recovered from 10 kg of raw materials by one roasting and sorting process.

The roasted product B is subjected to specific gravity sorting (specific gravity beneficiation) by a known wet method as a primary sorting to separate sediments and other substances, and the obtained sediments are separated by an electromagnetic induction sorter. Valuable metal was recovered by electromagnetic induction. The recovered product was chemically analyzed using a known method to determine the quality, and the amount of recovered metal was calculated.
As shown in Table 1, 376 g of copper could be recovered by one roasting and sorting step, but gold was 0.45 g and silver was 0.27 g, which were smaller than the recovered amount of Example 1. ..

(Comparative Example 1)
The roasted product C was only subjected to primary sorting by sieving using the same sieve having a mesh size of 1.5 mm as that used in Example 1, and the obtained sieve product was chemically analyzed.
As shown in Table 1, 308 g of copper could be recovered, but 0.05 g of gold and 0.04 g of silver were recovered, which was smaller than the recovered amount of Examples 1 and 2.

(Comparative Example 2)
The roasted product C was subjected to only the primary selection for specific gravity selection in the same manner as in Example 2, and the obtained sediment was chemically analyzed.
As shown in Table 1, 281 g of copper was recovered, 0.04 g of gold and 0.03 g of silver, which were smaller than those of Comparative Example 1.

(Comparative Example 3)
The roasted product D was only subjected to primary sorting by sieving using a sieve having a mesh size of 3.0 mm, and the obtained sieve product was chemically analyzed.
As shown in Table 1, the recovery of copper was as small as 216 g, and gold and silver could not be recovered.

(Comparative Example 4)
The roasted product E was subjected to only primary sorting by sieving using a sieve having a mesh size of 10.0 mm, and the obtained sieve product was chemically analyzed.
As shown in Table 1, the recovery of copper was as small as 85 g, and gold and silver could not be recovered.
As shown above, it was found that copper, gold and silver can be efficiently recovered by roasting scrap containing copper and gold or silver and then performing two-step separation of primary and secondary.

As is clear from Table 1, by performing the two-stage separation of primary sorting and secondary sorting under the sorting conditions according to the present invention, not only copper recovery but also gold and silver valuable metals can be expected to be recovered. I understand.
On the other hand, in Comparative Examples 1 and 2 in which the secondary sorting was not performed, not only copper but also other valuable metals such as gold and silver could not be efficiently sorted. Further, in Comparative Examples 3 and 4 in which the primary selection was performed with a large opening, the amount of recovery was small, and gold and silver could not be recovered.

Claims (5)

A primary selection product obtained by roasting copper and copper-containing scrap containing either or both of gold and silver as a valuable metal is used as an intermediate raw material, and the intermediate raw material is first selected and separated. And after getting the primary sorted roasted food
The first-sorted roasted product is secondarily sorted to recover the valuable metal contained therein.
A method for treating copper-containing scrap, which comprises subjecting the primary sort to one or both of the following (1) and (2) to recover valuable metals.
(Record)
(1) Heat and melt at 1100 ° C. or higher using an electric furnace, separate into a metal component and a slag component, and recover valuable metal as a metal component.
(2) After crushing and subjecting to the primary sorting, the primary sorted product and the primary sorted roasted product are separated.
Wherein the primary sorted matters,
Performing the above (1) to recover the valuable metal of the metal component,
Or after processing iterations performed the (2), valuable metals recovered through the implementation of the (1),
The primary sorted roasted product is secondarily sorted to recover the valuable metal contained therein. In the primary sorting, the intermediate raw materials are sieved using a sieving method using a sieve with an opening of 2.0 mm or less, the sieving product is used as the primary selection product, and the sieving product is used as the primary selection product. The method for treating copper-containing scrap according to claim 1, wherein the material is sorted as a roasted product. The method for treating copper-containing scrap according to claim 1, wherein the primary sorting is a specific gravity sorting method. The method for treating copper-containing scrap according to any one of claims 1 to 3, wherein the secondary sorting is a method of sorting using electromagnetic induction. The method for treating copper-containing scrap according to claim 1, wherein the intermediate raw material includes a crushed primary sorted product obtained by crushing the primary sorted product.

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