JPH11299387A - Cultivation of fish or shell - Google Patents

Abstract

PROBLEM TO BE SOLVED: To inexpensively culture fish and shell with materials produced as by-products effectively for a long period of time by casting a specific slag into the sea bottom under the farm. SOLUTION: The lumps of blast furnace slag occurring on the way of steel making are cast into the sea bottom beneath the farm or the circumference thereof. At this time, the lumps of the blast furnace slag are composed of the gradually cooled blast furnace slag, have a certain range in their sizes. The gradually cooled slag lumps of large sizes preferably project partially from the sludge layer formed on the sea bottom. In a preferred embodiment, the blast furnace gradually cooled slag are scattered on the sea bottom by 1-20 tons per 100 m<2> .

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of cultivating fish and shellfish such as sea bream, yellowtail, puffer fish, flounder, flatfish and shellfish, which is mainly performed in inland seas, inner bays, lakes and marshes.

[0002]

2. Description of the Related Art Conventional breeding methods for bream and yellowtail include a 30 m wide, 30 m long, 30 m wide, 80 m deep bay.
A live cage with a depth of about 15 to 20 m is installed, and in this, about 100,000 breams and about 4,000 breeds for hamachi are cultured. However, feces or residual food of these cultured fish settled around the lower part of the cage, and in some cases, the thickness of the sediment was about 100 to 300 mm. Like this, feces,
When the remaining bait sedimented, the sediment spoiled and oxidatively decomposed inside to generate hydrogen sulfide, and the seawater at the bottom became anoxic and acidic (about pH 5.8), causing virus. Furthermore, since a reverse flow is generated due to a temperature difference between the surface and the bottom of the seawater around September and December every year, the seawater with low oxygen at the bottom rises to the surface, and the fish cage becomes oxygen-deficient or rises. A virus (white spot disease) attaches to a fish and dies, and the mortality rate of more than 50% is 10%.
There was a problem that is about. Therefore, Japanese Patent Laid-Open No. 9-2
Japanese Patent No. 39375 discloses a mafic-based improver that introduces granules made of a material composed of a mafic-based granular material into water to self-disintegrate, thereby modifying the pH of the sea bottom to neutral or weakly alkaline. Proposed.

[0003]

However, the mica-based improver described in the above-mentioned publication becomes a powder while disintegrating on the seabed after being charged, and this powder gradually dissolves. Although the water quality is considered to be slightly alkaline, the sediment of fish dung and remaining food accumulates over time, and as a result, the magnesia-improving agent is buried in the sediment, There is a problem that falls gradually. In order to make up for this, it is necessary to periodically add a magnesia-improving agent from above, and as a result, a large amount of the magnesia-improving agent is required, resulting in a problem that the cost is increased. On the other hand, in ironworks, C
Blast furnace slow cooling slag containing a large amount of aO and SiO ₂ (a product obtained by gradually cooling and solidifying high-temperature slag from a blast furnace) is manufactured as a by-product, but is used as a building material such as ballast and sand. Has a problem that there is no effective use method. The present invention has been made in view of such circumstances, and it is an object of the present invention to provide a method for cultivating inexpensive fish and shellfish having long-term efficacy using blast furnace slowly cooled slag produced as a by-product in a steel mill. I do.

[0004]

According to the present invention, there is provided a semiconductor device comprising:
In the method for cultivating fish and shellfish as described, massive blast furnace slag generated in the iron making process is charged into the water bottom below or around the farm. Further, the method for cultivating fish and shellfish according to claim 2 is as follows:
2. The aquaculture method according to claim 1, wherein the massive blast furnace slag is a blast furnace slow cooling slag, the blast furnace slow cooling slag is large and small, and the large blast furnace slow cooling slag is a sludge layer formed on the water bottom. Some of them protrude from. And
Aquaculture method according to claim 3, wherein the seafood is the farming method according to claim 1 or 2, wherein the slowly cooled blast furnace slag, and 100 m ² per 1 to 20 tons put into the sea bed.

[0005] In the method of cultivating shellfish of claims 1 to 3, wherein, CaO and dicalcium silicate SiO ₂ and has molecular bonds (2CaO-SiO ₂₎ and free of Ca
Since massive blast furnace slag generated in the iron making process containing a large amount of O is introduced into the water bottom below or around the farm, a large amount of CaO is eluted into the water. As a result, a small amount of blast furnace slag is required, and as a result, the cost is low. Then, the surroundings become neutral or weakly alkaline, thereby suppressing the oxidative decomposition of fish manure and remaining bait and the generation of hydrogen sulfide. In particular, in the method for cultivating fish and shellfish according to the second aspect, the large blast furnace slowly cooled slag partly protrudes from a sludge layer formed on the water bottom, so that seaweed (waterweed) adheres to the protruding portion. In addition, the presence of CaO allows the attached seaweed to grow quickly. As a result, seaweed performs photosynthesis, oxygen in the water including seawater increases, and even if a reverse flow occurs, the upper farm is not deprived of oxygen. As in the method for cultivating fish and shellfish according to claim 3, the blast furnace slowly cooled slag is supplied to the water bottom 1.
It is preferable to add about 1 to 20 tons per 00 m ² , so that the blast furnace slow cooling slag containing CaO and SiO ₂ can be effectively used.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, embodiments of the present invention will be described to provide an understanding of the present invention. The composition of the blast furnace slowly cooled slag is as shown in Table 1, and it can be seen that CaO and SiO _{2 in the} dicalcium silicate state are the main components.

[0007]

[Table 1]

[0008] Slag having a particle size of under 5 mm is removed from the blast furnace slowly cooled slag, and a slag having a composition shown in Table 2 is used. Table 3 shows the results of a dissolution test of blast furnace slowly cooled slag having a particle size of 3 to 10 mm and ordinary limestone using fresh water.
As shown in the figure, the blast furnace slag is overwhelmingly CaO and S
It can be seen that the elution amount of iO ₂ is large. This is because, in the case of limestone, the structure is stable as CaCO ₃ ,
In the case of the blast furnace slowly cooled slag, it can be determined that dicalcium silicate is the main component and is easily dissolved in water.

[0009]

[Table 2]

[0010]

[Table 3]

The amount of the blast furnace slowly cooled slag is 100
About 1 to 20 tons in m ² , more preferably about 100 tons of blast furnace slow cooling slag per 20,000 m ² is charged. Here, when the blast furnace slow cooling slag is less than 1 ton at 100 m ² , the effect of CaO dissolution is small and the effect cannot be exhibited, and even if the blast furnace slow cooling slag exceeds 100 ton at 100 m ² , the effect is saturated. Not economical. In addition, when the blast furnace slow cooling slag is charged, the fish cage, which is an example of a cultivation farm provided at a predetermined location in the inland sea or cove, is moved to the bottom of the fish cage and its surroundings (from the position of the original fish cage). 20m
) And return the cage to its original position. The input cycle may be about once every 5 to 6 years, but when the input amount is small, the input is performed in a shorter period.

With the introduction of the slowly cooled blast furnace slag, the pH of the sediment below the pond is about 7.5 to 8.0 (50 after introduction).
Day) to correct the acidic condition. Then, on the bottom of the sea around the lower part of the cage, a large blast furnace slowly cooled slag, part of which protrudes from the sediment (sludge layer), is filled with seagrass for about 3 hours.
It was confirmed that it adhered in 0 days. In addition, the death of fish due to oxygen deficiency was 1/10 or less of the conventional one, and particularly, the rate of occurrence of mortality of 50% or more was 0%, which was extremely lower than the conventional one.

In the above-described embodiment, the description has been given of a fish cage arranged in the sea, but the present invention is also applicable to a fish cage provided in a lake. Furthermore, in the above-described embodiment, the description has been made using specific numbers. However, the present invention is not limited to these numbers. For example, the present invention is applicable to a case where the charging amount of the blast furnace slow cooling slag is further increased. Is applied.

[0014]

According to the method for culturing fish and shellfish according to claims 1 to 3, CaO contained in blast furnace slag elutes into water,
As a result, the pH of the water can be adjusted, and the sediment such as fish droppings and bait can be suppressed from being oxidized and decomposed. Can be reduced to In addition, since the dissolution of blast furnace slag in water is slow, it is not necessary to frequently refill blast furnace slag.Furthermore, blast furnace slag is a surplus by-product of the process of manufacturing steel, so it should be obtained at low cost. Can be. In particular, in the method for cultivating fish and shellfish according to claim 2, the blast furnace slag is composed of a blast furnace gradually cooled slag having a large and small size, and the large blast furnace slowly cooled slag is partially formed of a sludge layer formed on the water bottom. The protruding seaweed attaches and grows on this part in a short period of time, and the photosynthetic action of the waterweed can supply oxygen to the water near the bottom. Fatal accidents can be reduced.

Claims (3)

[Claims] 1. A method of cultivating fish and shellfish, wherein a massive blast furnace slag generated in the iron making process is introduced into a water bottom below or around a farm. 2. The massive blast furnace slag is composed of blast furnace slow cooling slag, and the blast furnace slow cooling slag is large and small, and the large blast furnace slow cooling slag is part of a sludge layer formed on the water bottom. The method for cultivating fish and shellfish according to claim 1, wherein the fish is projected. 3. The blast-furnace slow cooling slag is placed on the bottom of the water.
Aquaculture method according to claim 1 or 2, wherein the fish, characterized in that it is 0 m ² per 1 to 20 tons on.