JP3460591B2 - Sediment / seawater purification materials and purification methods - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention broadly belongs to sea area maintenance technology, and in particular, bottom sediment covered with seabed sludge similar to sand cover, materials used for purification of seawater, and bottom materials using the same.
Regarding the purification method of seawater.

[0002]

2. Description of the Related Art As a technique for purifying bottom sediment and seawater, there are methods such as covering the bottom mud with sand or dredging the bottom mud.

As the sand cover material, a material having only the effect of covering the bottom mud without chemical reaction such as sea sand or mountain sand, or a material such as lime capable of removing a part of P of the bottom mud by a chemical reaction. Is used. In some cases, the natural mud may cover the bottom mud in anticipation of the shore-building effect, but although seaweed adheres and propagates to the natural stone, there is little effect of preventing the elution of nutrients from the bottom mud, and Even if it is applied to the sea area where sedimentation is a problem, the improvement effect is not sufficient.

Natural stones and mountain sands need to be cut into mountains and collected, and it is becoming difficult to secure them due to recent environmental problems.

Recently, Japanese Patent Laid-Open No. 3-4988 discloses a sand covering material containing granular steelmaking slag as a main component. Specifically, when converter slag with a particle size of about 1 mm is used, the sand cover effect and H ₂ S due to CaO and Fe ₂ O ₃ components
It has been reported that the bottom and seawater can be purified by the chemical removal effect of PO ₄ ^3- .

[0006]

[Problems to be Solved by the Invention]
Since a large amount of contaminated floating mud flows into the sea area where seawater needs to be purified, if a converter slag having a particle size of about 1 mm, which is specifically described in JP-A-3-4988, is used, it will cover sand. Although it has the effect of purifying sediment and seawater in the initial stage, the mud gradually settles and deposits on the surface of the sand cover, and the surface of the sand cover is covered with sludge within a year, and the effect of purifying sediment and seawater is improved. Will disappear. In addition, since the converter slag having a particle size of about 1 mm is solidified, the biota recovery is slow, and the decomposition of accumulated sludge by organisms cannot be expected as much as natural stone.

The present invention has been made to solve such a problem, and has a long-term effect on bottom sediment and seawater purification, and a bottom sediment using steelmaking slag whose biota recover quickly.
An object is to provide a seawater purification material and a purification method using the same.

[0008]

[Means for Solving the Problems] The above problem is caused by a particle size of 10 m.
It is solved by a bottom sediment / seawater purification material containing 85 wt% or more of steelmaking slag of m or more.

85 wt% of steelmaking slag with a grain size of 10 mm or more
% Of the bottom sediment / seawater purification material prevents the steelmaking slag from solidifying, the voids are large and the mud settles in the voids, and the steelmaking slag surface is not covered with sludge. , The bottom sediment / seawater purification effect is maintained for a long time. In addition, in the gaps of the steelmaking slag, it becomes a suitable place for adhering diatoms, pearl oysters, shrimp, etc., the biota quickly attach and recover, and the sediment sludge is decomposed by the attached organisms, and the bottom sediment / seawater purification effect Is maintained for a long time.

90 wt% of steelmaking slag having a particle size of 20 mm or more
% If you use a sediment / seawater purification material that contains more than 50%, the intervals between steelmaking slags will be larger, the sustainability of the sediment / seawater purification effect will be further improved, and it will also serve as a home for fish such as goby, eel, and eel. validate.

It is to be noted that 8 steelmaking slags having a grain size of 10 mm or more are used.
Even if it contains 5 wt% or more or 90 wt% or more of steelmaking slag having a grain size of 20 mm or more, the balance can be sea sand, mountain sand, natural stone, or steelmaking slag having a grain size smaller than the above.

Since CaO is contained in the steelmaking slag,
CaO + H ₂ O → Ca (O
The H) ₂ reaction causes the steelmaking slag to collapse, producing small particles that enter the slag gap and reduce the bottom sediment / seawater purification effect. Due to the collapse of this steelmaking slag
Even if the seawater purification effect is reduced, if steelmaking slag with a grain size of about 10 mm or more is used, it will have a longer-term bottom sediment / seawater purification effect than with steelmaking slag with a grain size of about 1 mm. To prevent disintegration, steelmaking slag that has been aged with air, steam, autoclave, carbon dioxide, etc. may be used.

85 wt% of steelmaking slag with a grain size of 10 mm or more
% Sediment / seawater purification material containing more than 90% or steelmaking slag with a particle size of 20 mm or more containing 90 wt% or more sediment / seawater purification material with a thickness of 5 cm or more on the bottom mud ensures a sufficient slag gap As a result, a stable long-term effect on bottom sediment and seawater can be obtained.

As the steelmaking slag, not only slag generated in a converter, an electric furnace, a mixed pig wheel, etc., but also a hot metal pretreatment slag such as deslagging slag, desulfurization slag, dephosphorization slag and the like can be used.

The particle size of the slag may be adjusted by cooling and solidifying the molten slag, crushing it with a heavy machine or a crushing plant, and selecting using a sieve having a sieve of 10 mm or more, for example.

Installation of slag with a controlled particle size on the seabed
It can be performed by a conventional method using a gut ship or the like.

[0017]

[Example] (Example 1) A converter slag having various particle sizes shown in Table 1 was formed on the bottom mud having a large inflow of floating mud to a thickness of 2
The slag gap and the diatom settlement were visually observed with time by depositing 0 cm.

In Table 1, as the balance of the converter slag having a particle size of 10 mm or more, a converter slag having a particle size of less than 10 mm was used.

The results are shown in Table 1. In samples containing 85 wt% or more of converter slag with a particle size of 10 mm or more, slag gaps were observed even 3 years after deposition, long-term bottom sediment / seawater purification effects were obtained, and diatoms on the slag surface were obtained. It was confirmed that the biota had been attached and recovered early.

On the other hand, in the sample containing 15 wt% or more of converter slag having a particle size of less than 10 mm, the slag gap could not be observed in one month after all the deposits, and in three months,
The sedimentation of floating mud on all slag surfaces makes it impossible to confirm diatom settlement.

[0021]

[Table 1]

(Example 2) A converter slag adjusted to various particle sizes shown in Table 2 was deposited on the bottom mud of the seabed with a large amount of floating mud inflow to a thickness of 15 cm to visually observe the slag gap and diatom settlement. Observed over time.

In Table 2, as the rest of the converter slag having a particle diameter of 10 mm or more, a converter slag having a particle diameter of less than 10 mm was used.

The results are shown in Table 2. In the sample containing 90 wt% or more of converter slag with a particle size of 20 mm or more, slag gaps were observed even 5 years after deposition, and long-term bottom sediment / seawater purification effect was obtained. It was confirmed that the biota had been attached and recovered early. Furthermore, in this sample, habitat of fish such as goby was also observed in the slag gap.

On the other hand, in the sample containing 10 wt% or more of converter slag having a particle size of less than 20 mm, the slag gaps could not be observed in 3 years after all the deposits, and fish were also observed on the slag surface, but the slag No inhabitants were found inside the gap.

[0026]

[Table 2]

Example 3 A converter slag adjusted to various particle sizes shown in Table 3 and its aged slag were deposited on the bottom mud having a large inflow of floating mud to a thickness of 5 cm, and the slag was visually observed. The interstitial space and diatom settlement were observed over time.

In Table 3, as the balance of the converter slag having a particle size of 10 mm or more, a converter slag having a particle size of less than 10 mm was used.

The results are shown in Table 3. In the sample containing 85 wt% or more of converter slag with a particle size of 10 mm or more, in the aged sample, a slag gap was observed even 3 years after the deposition, and a long-term bottom sediment / seawater purification effect was obtained. ,
In addition, it was confirmed that diatoms had settled on the surface of the slag, and the biota had been attached and recovered early. On the other hand, in the sample not subjected to the aging treatment, the slag gap could not be observed within 2 years after the deposition, and the settlement of diatom was not observed.

Further, in the sample containing 90 wt% or more of converter slag having a particle size of 20 mm or more, aging was performed until the gap was not observed as compared with the sample containing 85 wt% or more of converter slag having a particle size of 10 mm or more. Although it is prolonged regardless of the presence or absence of the treatment, as in the case of the sample containing 85 wt% or more of slag having a particle diameter of 10 mm or more, the aging-treated sample was observed to have gaps for a long period of time.

[0031]

[Table 3]

[0032]

EFFECTS OF THE INVENTION Since the present invention is configured as described above, it has a long-term effect on the purification of bottom sediment / seawater, and a bottom sediment / seawater purification using steelmaking slag whose biota recover quickly. It is possible to provide a material and a purification method using the material.

Front page continued (58) Fields surveyed (Int.Cl. ⁷ , DB name) A01K 61/00 C02F 1/58 CDM C02F 1/58 CDQ C02F 11/00

Claims (6)

(57) [Claims] 1. A steelmaking slag having a particle diameter of 10 mm or more is 85 w
Purifying material for bottom sediment and seawater containing t% or more. 2. 90 w of steelmaking slag with a grain size of 20 mm or more
Purifying material for bottom sediment and seawater containing t% or more. 3. The bottom material / seawater purification material according to claim 1, wherein the steelmaking slag is aged. 4. A steelmaking slag having a particle size of 10 mm or more is 85 w
5cm thick on the bottom mud with bottom material / seawater purification material containing t% or more
This is the method for purifying bottom sediment and seawater. 5. 90 w of steelmaking slag having a particle size of 20 mm or more
5cm thick on the bottom mud with bottom material / seawater purification material containing t% or more
This is the method for purifying bottom sediment and seawater. 6. The method for purifying bottom sediment / seawater according to claim 4 or 5, wherein aged steelmaking slag is used.