JP2850064B2 - Processing equipment for used molten salt bath - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for dissolving a part or the whole of a used molten salt bath discharged from a plating apparatus or a metal electrowinning apparatus using a molten salt bath. Things.

[0002]

2. Description of the Related Art Conventionally, the treatment of a used molten salt bath discharged from a plating apparatus using a molten salt as an electrolytic bath, a metal electrowinning apparatus, and the like includes the steps of: a) disposing a used molten salt bath in a waste container; And cooling and coagulation, and dissolving and dissolving this with water. B) A method of directly pouring a used molten salt bath into a large-capacity water tank and dissolving and treating it.

[0003] As the above-mentioned method a), a large-capacity container is used as a disposal container, and all of the molten salt bath to be disposed is poured at a time to cool and solidify, or a small-volume disposal container is used. The method of cooling and solidifying the molten salt in several times is performed, and in any case, the treatment of cooling the molten salt in a container to a solid substance and then dissolving with water is performed, but the equipment used Which method is to be adopted is determined according to the size of the equipment and the status of peripheral equipment. And when dissolving the used molten salt in water according to these methods,
In general, the molten salt solidified in the waste container is directly introduced into the water tank in a large lump state, but the coagulated material may be finely pulverized and dissolved.

In the method a), however, there is no particular problem if the amount of the molten salt to be treated is small, but if the amount is large, it takes a long time for coagulation in a disposal container, so that much time is required for the treatment. Become like Also, when treating a large amount of molten salt bath, it is necessary to leave the container until the molten salt injected into the disposal container solidifies and solidifies. It is.

In addition, according to the above-mentioned method a), when the temperature of the molten salt to be treated is high, if the temperature of the disposal container is low, the container may be destroyed by deformation due to rapid thermal stress, and If water is attached, there is a risk of causing a steam explosion, so that it is necessary to heat the container to a temperature close to the molten salt temperature in advance in the treatment.

On the other hand, in the above-mentioned method b), unlike the method a), the use of a transport pipe makes it possible to omit the transportation step in a solid state, and thus it is easy to carry out a continuous treatment. There was a problem. That is, when the molten salt is dissolved in water, the heat of reaction increases the temperature of the molten salt dissolving water tank. However, when the water temperature is increased, the reaction between the water and the molten salt is explosively accelerated. Water tank is required. Therefore,
In addition to the increase in equipment cost, the installation space for the processing apparatus also increases. In particular, when the molten salt is cooled, it hardens and consequently clogs the transport piping, so it is not easy to transport the molten salt to a distant place. Therefore, the above-described large (large capacity) It is not preferable to install the processing equipment of (1). Further, in such a large-sized facility, it is difficult to capture fumes generated by a reaction when the molten salt is dissolved in water, which is disadvantageous in terms of preventing environmental pollution.

In view of the above, an object of the present invention is to establish a means for quickly and accurately treating a used molten salt without requiring large-scale equipment and processing space. .

[0008]

The inventors of the present invention have conducted intensive studies to achieve the above object, and as a result, have found that "for rapid treatment of used molten salt, water is used in a molten state. The "dissolution method" is by far the most advantageous practical means, but the "reaction heat generated when dissolving the molten salt in water", which is a problem in this method, is effectively removed by circulating the water in the water tank. If the temperature rise in the water tank is suppressed by circulating water, the dissolution treatment can be carried out without causing the reaction between the molten salt and water to proceed explosively even if a small water tank is used. Will be able to do it. "

The present invention has been completed on the basis of the above findings and the like. "The treatment apparatus for a used molten salt bath is connected by a molten salt transport pipe having at least one flow control valve inserted therein. A storage tank for the used molten salt to be used and a water tank for dissolving the molten salt, and a system for replenishing and circulating water in the molten salt dissolving water tank. In that it enables miniaturization and at the same time enables quick and accurate processing. "

Hereinafter, a treatment apparatus for a molten salt bath according to the present invention will be specifically described based on examples. FIG. 1 is a schematic diagram relating to one embodiment of a molten salt bath treatment apparatus of the present invention, and includes a storage tank 2 for storing a molten salt 1 discharged from a plating apparatus using a molten salt bath or a metal electrowinning apparatus. A water tank 3 for dissolving the molten salt, the storage tank 2 and the water tank 3 being connected by a "molten salt transport pipe 5 having flow control valves 4, 4 inserted at two locations", The water tank 3 is provided with a water supply / circulation pipe 6.

The apparatus of the embodiment shown in FIG. 1 is an exhaust system for exhausting "a fume generated by a reaction when a molten salt is dissolved in water", which is an auxiliary equipment appropriately provided. Pipe 7, a device for measuring the water temperature in the water tank comprising a temperature measuring element 8 and a temperature measuring device 9, and a flow control valve attached to the molten salt transport pipe 5 in response to a signal from the temperature measuring device 9.
4, 4 are provided with a valve opening control device 10 for sending an opening adjustment signal. Here, reference numeral 11 denotes a fan, 12 denotes a pump, 13 denotes an overflow pipe, and 14 denotes water.

[0012]

When the molten salt is to be treated by the above apparatus, the flow control valves 4, 4 are first opened, and the molten salt 1 in the storage tank 2 is continuously poured into the water tank 3. At this time, when the molten salt to be treated is at a high temperature, the molten salt transport pipe 5 is preferably heated to the molten salt temperature in advance. This is to prevent the molten salt from solidifying in the transport pipe and causing clogging of the pipe. The fumes generated when the molten salt 1 comes into contact with and reacts with the water 14 in the water tank 3 are sucked by the exhaust pipe 7 and
Is sent out of the device.

By the way, as described above, the reaction heat generated when the molten salt 1 is dissolved in the water 14 in the water tank 3 tends to raise the water temperature and induce explosive acceleration of the reaction. In the apparatus of the present invention, a water replenishing / circulating device is installed in the water tank 3, and the rise in water temperature can be suppressed by "replenishing new water into the water tank 3" or "circulating water 14 in the water tank 3". As a result, the above adverse effects are effectively prevented.

That is, in the apparatus illustrated in FIG.
Is poured into the water tank 3, and water is replenished into the water tank 3 by the pump 12 according to a rise in the water temperature in the water tank 3. Therefore, the water tank 3
The internal water 14 increases to raise the water level while suppressing a rise in water temperature. When the water level exceeds a predetermined amount, the water overflows from the overflow pipe 13 to the outside of the water tank. The water to be sent into the water tank 3 by the pump 12 may be fresh water, or the overflowed water may be circulated through the overflow pipe 13. However, when using overflow water, it is preferable to circulate after cooling using a heat exchanger or the like since the water temperature is rising. When using the overflowed water, a tank for temporarily storing the overflowed water may be provided separately. Of course, in some cases, merely circulating the water 14 in the water tank 3 may keep the water temperature below a desired value.

Further, if the increase in water temperature does not stop even after replenishing and circulating water into the water tank 3, the opening of the flow control valve 4 is adjusted to adjust the amount of molten salt 1 flowing into the water tank 3. Adjust As a result, a rise in water temperature can be more reliably suppressed. The apparatus illustrated in FIG. 1 can perform this operation more accurately. That is, in this device, a temperature measuring device 9 having a temperature measuring element 8 is arranged in the water tank 3 and configured to send a temperature signal relating to the water temperature in the water tank to the valve opening control device 10. The device 10 calculates the inflow amount of the molten salt such that the water temperature becomes a predetermined target temperature based on the temperature signal from the temperature measuring device 9, and sends a signal based on the calculated amount to the flow control valve 4 to determine the opening degree. Control. Therefore, adjustment of the water temperature in the water tank, that is, advanced control of the reaction between the molten salt and water can be easily performed.

The flow control valve 4 installed in the molten salt transport pipe 5 may be installed at only one place, but preferably installed at two or more places if possible. This is because, when the length of the transport pipe from the storage tank 2 for the used molten salt to the water tank 3 is long, even if the flow rate is controlled by one valve, the time required for the molten salt to flow from the valve position to the water tank is long. This is because there is a risk that response delay may occur in control. Of course, when the length of the transport pipe is short enough not to cause a response delay, it goes without saying that the flow control valve may be attached to only one place.

Next, the results of processing an aluminum chloride-based molten salt bath at 200 ° C. using the molten salt bath processing apparatus (water tank capacity: 400 liters) shown in FIG. 1 will be described. In the treatment of the aluminum chloride-based molten salt, the amount of circulating water is required to be at least 5 times the amount of molten salt processed per unit time, and the target water temperature in the water tank is 80 ° C or lower, preferably 50 ° C or lower. Based on these conditions, the molten salt transport pipe 5 is also preheated to 200 ° C. since the molten salt bath to be treated is 200 ° C. during the treatment, and fresh water is supplied to the water tank 3 using fresh water. The volume was 80 liters per minute.

Under these conditions, a continuous water dissolution treatment of about 700 kg of waste aluminum chloride-based molten salt was carried out. As a result, the amount of molten salt flowing into the water tank during the treatment was adjusted to about 7 kg per minute, and the water temperature in the water tank: 50 The process was completed in about one hour while maintaining the temperature at or below ° C.

[0019]

As described above, according to the present invention, it is possible to provide a compact apparatus capable of rapidly processing used waste molten salt, which greatly contributes to improving the operability of plating and electrolytic refining. And industrially useful effects.

[Brief description of the drawings]

FIG. 1 is a schematic explanatory view of an example of a molten salt bath treatment apparatus according to the present invention.

[Explanation of symbols]

 Reference Signs List 1 molten salt 2 storage tank 3 water tank 4 flow control valve 5 molten salt transport pipe 6 water supply / circulation pipe 7 exhaust pipe 8 temperature measuring element 9 temperature measuring device 10 valve opening control device 11 fan 12 pump 13 o Bar flow piping 14 Water

Continued on the front page (72) Inventor Yasuhiro Yamamoto 4-5-33 Kitahama, Chuo-ku, Osaka-shi, Osaka Inside Sumitomo Metal Industries, Ltd. (72) Inventor Junichi Uchida 4-5-33 Kitahama, Chuo-ku, Osaka-shi, Osaka Within Sumitomo Metal Industries, Ltd. (72) Inventor Ken Abe 4-5-33 Kitahama, Chuo-ku, Osaka-shi, Osaka Prefecture Inside Sumitomo Metal Industries, Ltd. (72) Kunihiro Fukui 4-5-Kitahama, Chuo-ku, Osaka, Osaka No. 33 Sumitomo Metal Industries, Ltd. (72) Inventor Junkichi Yoneda 4-6-22 Kannonshinmachi, Nishi-ku, Hiroshima, Hiroshima Prefecture Mitsubishi Heavy Industries, Ltd.Hiroshima Works (72) Inventor Norio Hashimoto 4 Kannonshinmachi, Nishi-ku, Hiroshima, Hiroshima 6-22, Mitsubishi Heavy Industries, Ltd.Hiroshima Works (72) Inventor Toshio Taguchi 4-6-2-2 Kanon Shinmachi, Nishi-ku, Hiroshima-shi, Hiroshima Mitsubishi Heavy Industries, Ltd.Hiroshima Works (58) Field surveyed (Int.Cl. ⁶ , DB name) C25D 21/16-21 / 18,3 / 66 F27D 15/00-15/02

Claims (1)

(57) [Claims] 1. A method for dissolving a molten salt, comprising a storage tank for a used molten salt and a water tank for dissolving the molten salt, the storage tank being connected to a molten salt transport pipe having a flow control valve interposed at at least one place. An apparatus for treating a used molten salt bath, comprising a water tank provided with a water replenishing / circulating device.