JPH08187488A - Treatment of marine products containing cadmium - Google Patents

Abstract

PURPOSE: To detoxify a large amt. of marine products having fear containing cadmium without using an expensive plant to treat them as ash, for example, for landfilling. CONSTITUTION: Marine products containing cadmium are dried (2) in a drying oven and, for example, a heavy metal insolubilizing treatment agent such as a chelating agent is added to the dried marine products to insolubilize cadmium contained in marine products (5).

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a method for treating marine products containing cadmium.

[0002]

2. Description of the Related Art It has been conventionally known that marine products, especially scallops, contain trace amounts of cadmium, which is a heavy metal harmful to the human body. The content of cadmium in such scallops is particularly large in the so-called uro after removing the scallops.

Originally, this uro is valuable as a fertilizer for livestock, but in recent years, it has not been used so much as a fertilizer for livestock from the viewpoint of the food chain.

On the other hand, scallops often take out only the scallops and provide only this part to the market as food, and as a result, when a large amount of scallops are taken out, a large amount of uros are processed accordingly. There must be. Moreover, it emits a strong offensive odor and must be treated as soon as possible.

However, when a large amount of uro is accumulated, the amount of cadmium contained also becomes large, and careless treatment is not preferable in terms of environmental hygiene. For this reason, in a place where a large amount of uro is produced, a dedicated plant is installed, and the detoxified product is used as ash for landfill, for example.

[0006]

However, a plant for treating such a uro is very expensive, and its installation site is limited. Therefore, it can be used as landfill ash in some places. I could not do it. as a result,
In places where there was no plant, these uros were transported to the mountains and backfilled in the soil for processing. However, the transportation of these marine products from the processing plant to the mountains becomes expensive, and improvement is required.

In view of such conventional problems, the present invention detoxifies a large amount of marine products that may contain cadmium without using an expensive plant and treats them as landfill ash, for example. It is an object of the present invention to provide a method for treating marine products containing cadmium that can be processed.

[0008]

A method for treating cadmium-containing marine products according to the present invention for achieving the above object is to dry cadmium-containing marine products, and then to dry the marine products. It is characterized in that a cadmium contained in the marine product is made to be uneluted by adding a treatment agent for eluting heavy metals.

[0009]

According to the method for treating marine products according to the present invention, marine products containing cadmium can be converted into insoluble substances by a chemical change.

Therefore, it can be used as ash for landfill.

[0011]

An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 shows a processing method according to the present invention in the order of steps.

In the first step 1 of this embodiment, first, a large amount of uro after removing the scallops of scallops is collected in a certain place in a processing factory. Among these uro, heavy metals such as cadmium are contained in trace amounts especially in the liver part. In the second step 2, these accumulated objects to be dried are dried. In this drying, the heating source may be electricity or steam. The third step 3 is a step of selecting the dried objects to be dried according to the size of the particles, and the size of selecting the articles to be dried is appropriately set. For example, when scallop uro is dried, the part of the string that does not contain cadmium, which is a protein, is present in a large state, and the part of the liver that contains cadmium is processed into a fine powder. Therefore, in this 3rd process, it will be divided into a liver part and a string part. In addition, in the fourth step 4, the heavy metal elution treatment agent is added to the powder of fine particles containing cadmium among the materials to be dried selected in the third step 3. Such a treating agent is one which solidifies ash by the sulfurization method, and various agents can be mentioned as usable agents. For example, a treating agent such as a trade name RHF marketed by Issei Shokai Co., Ltd. There is. In addition to this, there is a chelating agent for converting a water-soluble heavy metal into an insoluble substance by a chemical change. The coordination bond of the chelating agent has NN coordination,
NO coordination, NS coordination, OO coordination, OS coordination, S
The polymer chelating agent having --S coordination or the like and used as a fly ash treating agent forms an intramolecular complex salt of a heavy metal by utilizing the bond of these ash particles.

The processing method according to this step will be specifically described below. First, the hopper 5 used in the first step 1 contains a large amount of uro. These uros may be manually put into the hopper 5, or may be automatically put in by a conveyor or the like. A connecting pipe 6 is installed at the lower end of the hopper 5, and the connecting pipe 6 is connected to the dryer 7. The dryer 7 is for drying an object to be dried by electricity or steam, and it is preferable that even an object to be dried containing a large amount of water, such as a scallop, can be dried in a short time. An example of such a dryer is a cyclone dryer commercially available from Sankyo Engineering Co., Ltd. This dryer is equipped with rotary blades called cyclone fins inside, and the blades scrape up the material to be dried. Further, in this dryer 2, the inner peripheral wall of the cylindrical body serves as a heating surface, and the material to be dried is dried by the heat generated from this. The material to be dried, which has been scraped up by the cyclone fins, is pushed in a thin film onto the wall surface which is the heating surface, and the material having a higher water content is preferentially contacted with the heating surface and dried. However, such a dryer 7 is not particularly limited, and, for example, a dryer using far infrared rays can be effectively used.

A duct 8 for discharging waste steam is connected to the upper part of the dryer 7. This duct 8
The waste steam that has passed through is introduced into the cooler 9 where it is rendered harmless, and is taken into the deodorizer 10 to finally remove the odor.

On the other hand, the material to be dried which has been dried in the dryer 7 is then discharged into a discharge pipe 11 having a screw conveyor.
And is accommodated in the sorting device 12 via the discharge pipe 11. The sorting device 12 is provided with, for example, a blower at the upper part thereof, and a mesh-shaped sieve for sorting the size of particles is arranged in the vicinity of the outlet.

When air is discharged from the blower,
The fine particles on the sieve fall down through the sieve,
On the other hand, the large dried product remaining on the sieve is discharged to the outside through the discharge port 14. For example, when a scallop uro is dried, the dried product discharged from the discharge port 14 is a part called a string, and since this string is a protein that does not contain cadmium, it is effectively used as a bird's food or the like. be able to.

On the other hand, a processing chamber 13 in which a heavy metal non-eluting treatment agent is mixed is installed below the sorting device 12. Into the processing chamber 13, the above-mentioned heavy metal non-eluting treatment agent such as RHF and water are mixed together. This allows
The ashed powder containing cadmium has a volume of 1/2 to 1
It decreases to about / 3. The powder treated in this way is
Since the elution amount (mg / l), which is the legally regulated value, is 0.3 or less, it can be disposed of without any problem as landfill ash.

Therefore, even if it is used as backfilling soil in a landfill near a seafood processing plant, there is no risk that the heavy metal will be melted, and therefore it can be disposed of at such a place.

In the above embodiments, the scallop uro was used as an example of the seafood, but the seafood is not limited to scallops. For example, uro such as mussels can be similarly treated. it can.

In the above embodiment, the dried product containing cadmium was dried, and then the cadmium was treated by adding the heavy metal eluting treatment agent, but instead of drying, the marine products were burned, Needless to say, the same effect can be obtained by adding a heavy metal immobilization treatment agent to the combustion ash.

[0021]

As described above, according to the method for treating cadmium-containing marine products according to the present invention, cadmium and the like can be contained with relatively simple equipment without using a large plant. The ash of marine products can be processed below the legally regulated value.

Therefore, it can be disposed of as ash for backfilling.

[Brief description of drawings]

FIG. 1 is a chart showing the method of treating a marine product containing cadmium according to the present invention in the order of steps.

FIG. 2 is a plan view showing an example of a concrete apparatus of the processing method according to the embodiment.

[Explanation of symbols]

 5 ... Hopper 7 ... Dryer

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI Technical display location B09B 3/00 B09B 3/00 304 Z

Claims (1)

[Claims] 1. A marine product containing cadmium is dried, and then a cadmium contained in the marine product is made to elute by adding a heavy metal non-eluting treatment agent to the dried marine product. A method for treating marine products containing cadmium.