KR960011800B1 - Recovering method and apparatus of al plug - Google Patents

Abstract

This method is applied to recovering of Al cap from two-piece steel can composed of steel body and aluminium cap used for drinks. Compared with general recovering method of waste steel can by compressing without separating of Al cap, this method provides a recovery of expensive Al cap and a prevention of oxidation of molten metal without removing of outside coating material and of inside lacquer during melting at steel making furnace. This method consists of charging waste two-piece steel can in the heating furnace(1), heating and crashing in a rotary killen(3) type furnace at 590-610deg.C during 5-10min., removing coating material of outside and lacquer of inside, separating Al cap from steel body by impacting on another of scrapped cans and the wall of furnace, screening and sorting of separated Al cap and steel body.

Description

Separation and recovery method of aluminum stopper from steel cans by heat shock method

1 is a device schematic of the present invention.

2 is a process flowchart of the present invention.

3 shows the stopper and the body separated after tumbling the steel closed can for 5 minutes at 590 ° C.

4 shows the result of the plug / body separation test of steel closed cans according to temperature and time:

Figure 4a is a sample tumbling 30 minutes after heating 550, 570, 590, 610 ℃ from the left.

Figure 4b is a sample tumbling for 1, 5, 10, 20, 30 minutes from the left at 590 ℃.

Figure 4c is a sample tumbling for 1, 5, 10, 20, 30 minutes from the left in the case of 610 ℃.

The present invention relates to a method and apparatus for separating and recovering an aluminum stopper from a steel waste can by a heat shock method, and more particularly, after collecting a steel waste can for beverages in which the body is made of steel and the stopper is made of aluminum. Is heated in a rotary kiln-type furnace to remove external paint and internal lacquer, and at the same time, the cans collide with each other, or the impact of the furnace wall separates the aluminum plug from the steel body and recovers it separately.

This method can be used in factories and businesses that collect aluminum and steel cans, dissolve and recycle them.

Conventional two-piece steel cans for beverages are made of aluminum alloys of 5182 and 5082 series, although the body is made of steel. To recycle the steel cans, up to now, the aluminum cans in the steel cans have been recovered. It is not.

In the conventional method, the collected steel waste cans are collected and compressed into piles or charged into steelmaking furnaces together with other kinds of scrap metals to be used as steelmaking raw materials. Therefore, aluminum caps, which are more expensive than steel, cannot be recovered separately. Since paint and lacquer are not removed, the paint and lacquer are vaporized during dissolution, so that the molten metal is easily in contact with the air, resulting in high oxidation loss.

The present invention is to remove the above-mentioned drawbacks in detail in connection with the gist of the accompanying drawings as follows.

First, referring to the apparatus of the present invention, as shown in FIG. 1, the motor 4 is installed on the support 8, and the motor 4 is connected to the rotary shaft of the kiln 3, and the opposite shaft is installed on the kiln bearing 5, and the kiln 3 is provided. In other words, the heating wire (7) is installed outside the inside of the heating furnace (1) is connected to the thermocouple (6) exposed to the outside of the furnace lid (2) is a device installed.

The sample used in the present invention used a two-piece steel closed can for beverages manufactured in Korea, the stopper material is Al-5000 series such as aluminum alloy number 5182, 5082.

The principle of the present invention is that the melting point of iron is 1539 ℃, the melting point of aluminum is 660 ℃, the difference between the melting point between the two metals, the weaker the strength of the metal at a high temperature, using a property that is easily deformed or destroyed by a small impact In this case, when the steel closed can is heated to near the melting point of aluminum, the steel can can be vulnerable and easily detached from the steel body while being easily destroyed.

Here, the furnace may be a rotary kiln of a conventional type using gas or fuel in addition to the furnace of the type claimed in the present invention.

In carrying out the present invention as described above, the steel waste can is rotated by heating at a temperature of 590-610 ° C. for at least 5 minutes using a furnace 1 in the form of a rotary kiln 3 as shown in FIG. As the paint and internal lacquer are removed and the cans are hit by the kiln wall, the aluminum stopper is mostly broken into pieces of 1 cm or less in diameter, which is separated from the steel body and falls on the bottom of the kiln. The steel body is only removed with paint and lacquer. Since the shape is kept round, the sample inside the kiln can be taken out and screened to separate and recover the aluminum stopper broken into pieces and the steel body keeping the shape.

If the heating temperature is high, the heating time is short, and if the heating temperature is low, the heating time is long.

In addition, the outer paint and the inner lacquer of the waste can is thermally decomposed and removed when the waste can is heated. The sample can be sufficiently removed by heating the sample for 30 minutes at 490 ° C. and keeping it at 550 ° C. for 5 minutes.

Therefore, in order to simultaneously perform the effect of separating the aluminum plug while removing the paint and lacquer of the steel waste can in a short time, the heating temperature must be higher than 590 ° C.

Steel closed can cap and body separation test in the present invention was carried out in the furnace (1) of the rotary kiln (3) form as shown in FIG.

The summary of the operation method is shown in the flowchart shown in FIG.

In Figure 2, the paint and lacquer removal and heat shock processes are divided for convenience of explanation and are treated as a process in actual operation.

After the sample is charged into the kiln and the furnace is heated to a certain temperature, the kiln containing the sample is loaded into the furnace, and both ends of the rotary shaft of the kiln are connected to the bearing (5) of the motor (4) and the support shaft. When the sample temperature reached the test temperature while the paint and lacquer of the internal sample were removed, the motor was rotated at a speed of 100 rpm.

In the heating apparatus of the present invention, it took about 20-30 minutes until the test temperature was reached after charging the sample.

The charged steel cans are separated from the steel body as they are tumbling in the kiln and at the same time the aluminum stopper heated directly below the melting point is crushed by the impact hit against the kiln wall.

In the present invention, the sample was heated at 550 ° C., 570 ° C., 590 ° C., and 610 ° C., and the effect of plug separation with temperature and time was investigated while heating the sample for 1, 5, 10, 20, and 30 minutes.

Example 1

Paint and lacquer removal of steel cans at 590 ° C and separation test of aluminum stopper When tumbling at 590 ° C for 5 minutes, the stopper was broken and separated in FIG. 3.

In the photo of Fig. 3, the pieces of finely crushed aluminum can be seen next to the steel can body with the stopper removed.

The reason why the can stopper is crushed by heating and tumbling is that the melting point of Al-5182, the stopper material of the steel closed can, is 612-630 ° C. Therefore, when the steel closed can is heated up to this temperature, the metal recrystallizes and crystal grows inside the aluminum stopper. This occurs and melting begins to occur at the recrystallized crystal boundary. In this state, when the waste can sample is subjected to an impact, the stopper is easily broken along the grain boundary and separated from the steel body.

The steel body of the waste can is reddish brown unlike aluminum stopper because the surface is oxidized with iron oxide as paint and lacquer are removed during heating.

Example 2

The aluminum stopper separation test samples of steel waste cans were heated at 550, 570, 590, and 610 ° C for 1, 5, 10, 20, and 30 minutes.The stopper was not crushed at 550 ° C and 570 ° C. At 590 ° C and 610 ° C, it could not be separated in 1 minute, but after 5 minutes of tumbling, the stopper was broken and separated.

4 is a photograph showing the aluminum plug separated from the steel body according to the heating temperature and the tumbling time.

Photograph (a) shows the stopper removed after tumbling for 30 minutes in order of 550, 570, 590, 610 ° C from the left.

The plug was not separated at 550 and 570 ° C, and the plug was separated at 590 ° C and 610 ° C.

Photos (b) and (c) show the effect of separating the stopper and body over time at 590 ° C and 610 ° C. When (b) is 590 ° C, (c) is 610 ° C. From left, 1, 5, 10 Followed by 20 and 30 minutes.

At 590 ° C and 610 ° C, the stopper cannot be separated by tumbling for 1 minute, but if it is tumbled for more than 5 minutes, the stopper is broken and easily separated from the body.

In addition, the particle size distribution was investigated by sieving the plug particles crushed by heating and tumbling at 590 ℃ and 610 ℃.

The sieves used for the sieving were five sizes of 1.5, 1.0, 2.36, 5.0, and 7.93 mm.

After classifying the crushed particles, the weight of each sorted sample was measured and divided by the total weight of the crushed particles to investigate the weight distribution by particle size. In both cases of 590 ℃ and 610 ℃, most of them were 5mm or less in size and 1mm in size. There were also many fine particles below.

[Comparative Example]

If the heating and tumbling at 590 ℃ and 610 ℃ for more than 5 minutes, the aluminum plug is broken from the steel can can be broken and separated, the higher the heating temperature will be more surface oxidation of aluminum, the metal recovery rate is expected to decrease during melting.

From these results, it was judged that the plug and body separation of the waste can was enough to tumble for 5-10 minutes at 590 ° C.

The 250mm two-piece steel cans currently in circulation are about 29 grams in weight, of which the stopper is aluminum with a stopper weight of about 3.5 grams and accounts for about 12% of the total weight of the steel can.

The present invention is a method to be applied when collecting and recycling the steel waste cans for beverages whose body is steel and the stopper is made of aluminum, by removing the paint and lacquer of the waste can body when recycling the steel waste cans by carrying out the present invention Since the steel body in the can and the aluminum stopper, which is 12% of the total weight of the can, can be separated and recovered separately, the can can be recycled with uniform components during recycling, and aluminum can be recovered without loss more expensive than steel. There is an advantage.

Claims (2)

Beverage cans are steel cans and caps made of aluminum and heated in a rotary kiln type furnace for 5 minutes at 590-610 ° C. to remove external paint and internal lacquer, while rotating cans from rotary kilns. The steel by heat shock method characterized in that the aluminum plugs are separated from the steel body by the impact of the impact on the walls of the furnace or the wall of the furnace, and the sieves are separated by a sieve and sifted to recover the stopper and the steel body which are broken into pieces. Separation recovery method of aluminum stopper from waste can. The motor 4 is installed on the support 8, connected to the rotary shaft of the kiln 3, and the opposite shaft is installed on the kiln bearing 5, and the heating wire is installed outside the kiln 3, that is, inside the furnace 1. 7) A separate recovery device for the aluminum stopper from the steel closed can by the heat shock method, characterized in that the thermocouple (6) is exposed and installed outside the furnace lid (2) by installing and connecting to it.