KR100220652B1 - Magnesia type modifier of water quality and bottom material - Google Patents

Abstract

The present invention provides an improving agent capable of reforming the water quality and the poor quality of the deteriorated closed water.

It is comprised by the 1 type (s) or 2 or more types of material of a high earth granular material, and its MgO conversion content rate is 30 weight More than 20 weights of moisture It is also characterized in that the self-decomposition after the addition in water.

Description

Water and low quality magnesium compound-based improver

1 is a graph showing changes over time of pH transitions in Example 6, Comparative Example 1 and Comparative Example 2 of the present invention.

The present invention relates to a water or low quality magnesium compound-based improving agent. More specifically, the present invention relates to an improving agent for improving the quality of water and poor quality by spraying the deteriorated closed water.

In recent years, closed waters such as inland seas, bays, and lakes, which have a large source of pollution in the medium, have a large pollution load, and contaminants tend to accumulate. Therefore, eutrophication proceeds, and water and low quality pollution proceeds. have. In order to cope with this, the Act on the Prevention of Water Pollution, the Special Measures for Environmental Conservation of the Seto Inland Sea of Japan, the Special Measures for the Preservation of Appeal Water Quality, and the Regulation on the Discharge of Nitrogen and Phosphorus on Appeals are enacted.

In the closed waters represented by Seto Inland Sea, the influx of phosphorus and nitrogen is stagnant, and red tide causes fishery damage. In addition, fresh water red tide and green powder are abnormally generated in an appeal that is a source of water for drinking water, which causes problems with filtration and strange smell of water supply facilities.

In addition, toxic hydrogen sulfide is generated in the low quality due to the occurrence of red tide and poor oxygen lumps, and thus the damage caused by mass slaughter of fish has been reported. Therefore, in order to prevent mass slaughter of fish farms, the prevention of hydrogen sulfide generation is an urgent problem.

In response to these problems, specific methods such as tillage, aeration (air exposure), drug spraying (lime, store), radiation, and dredging are being implemented as improved technologies.

Cultivation is a method of forcibly stirring, inverting, and diffusing a poor surface layer to cultivate a cultivator to physically contact undecomposed organic matter in an oxygen free or anoxic state with oxygen.

Aeration is a method of forcing air into the seabed to increase the dissolved oxygen concentration. Lime foaming is a method of sparging quicklime to maintain the pH towards alkali and to fix and remove contaminants as poorly soluble compounds.

Clay spraying is a method of spraying clay minerals (montmorillonite-based clays whose main components are SiO2 and AL2O3), coagulating and precipitation of organic suspensions in water and coating of low quality.

Radiation is a method of completely covering the reservoir with sand to block the contaminated surface and the water phase.

Dredging is a method of recovering pollutants themselves and disposing of them in other places.

In the application of the above improvement techniques, the improvement technique is selected, including problems (diffusions of pollutants, contamination of water bodies, suspension of temporary production activities, treatment of sludge generated secondarily) and implementation costs. It becomes necessary.

The chemical spraying method of spraying clay or lime has an advantage that the implementation cost is extremely low for other improvement techniques, the pollution of the surrounding water is small during the operation, and can be easily performed.

However, in the lime spraying method, which is most inexpensive in the conventional drug spreading method, the publication of Japanese Patent Laid-Open No. 2-218488 points out the following points with respect to quicklime to be administered.

1) Quicklime may generate heat if it is in contact with water, which may cause fire or burns, and requires great care in handling it.

2) Quicklime breaks down and breaks down when it comes in contact with water. Therefore, the water in the spraying area may be contaminated with white, causing harmful effects such as water pollution.

3) Quicklime is relatively soft and susceptible to mechanical shock or friction, so in the case of aerial spraying, smoke is likely to occur and damage is likely to occur in the vicinity. For this reason, in recent years, the method of spraying slaked lime which is easy to handle instead of quicklime has also been proposed.

Quicklime administered with lime spray hydrates from oxides to hydroxides. Ishishita Shimoto, "Gypsum and Lime" Volume 234 (1991), p. 102, right column In line 11, "the main component of lime quickly changes to calcium hydroxide in the seabed. Since sea ions contain about 1300 ppm of magnesium ions, calcium ions are replaced with magnesium ions to form magnesium hydroxide. ”

Magnesium hydroxide produced here is newborn magnesium hydroxide, and its particle diameter is a superfine particle which shows a colloidal phase by submicron. For this reason, in water, it spreads easily by convection and produces cloudiness (smoking). Segui is the book of Lime, vol. 337 (1984), p. 34, line 17 In line 1 on page 35, "Even if quicklime enters seawater, it becomes the same as hydrated lime. The clouding itself is not desirable, but the fine particles are suspended in the seawater and have a large influence on others. Therefore, it is necessary that the improver does not cause such smoking.

On the Toxicity of Hydrogen Sulfide Iwasita et al., “Gypsum and Lime,” Volume 234 (1991), page 102 In line 14, "Hydrogen sulfide dissolved in water is acutely toxic to fish and shellfish because it exists in undissociated state (H ₂ S) below pH 7. For example, the semi-lethal concentrations for trout, invertebrates and cats are 0.9987 ppm, 0.20 ppm and 25 µg / kg, respectively, and the effects on living organisms are extremely large.

Regarding the generation of hydrogen sulfide in the poor quality, the generation mechanism has been explained as a relationship between sulfate reducing bacteria and hydrogen sulfide, with the pH of the environmental water generated as a factor. Saito, “Lime”, vol. 359 (1985), p. 17 In line 11, "When organic matter deposited on the sea floor decomposes, oxygen is consumed, the bottom part becomes anoxic, and the anaerobic bacterium sulfate reducing bacterium starts activity. This activity is active on the surface of organics, and these bacteria reduce the sulfates and release the sulfurized water channels. Hydrogen sulfide generated from Journey is almost due to the action of these bacteria. However, this bacterium also has a weak point. It does not multiply unless the seawater becomes acidic to some extent. Conversely, they do not proliferate in slightly alkaline and cannot survive at pHs above 8.5. For this reason, lime sprayed on the sea floor keeps the pH in the seawater alkaline and inhibits the proliferation of sulfate reducing bacteria for a long time, thereby preventing the generation of hydrogen sulfide.

Three Lime, Vol. 337 (1984), p. 33 In line 15, "In addition, the range of pH value of the environment suitable for proliferation is defined for each bacterium. In the case of sulfate reducing bacteria, it is 6.5 to 7.5, ie, neutral, and cannot survive in alkaline above 8.5. PH of seawater is 8.2 Since it is slightly alkaline, the reduction of sulphate does not occur in a normal state. After all, hydrogen sulfide is generated as long as conditions such as organic acid generation, pH decrease and anoxic acid are satisfied due to the decay of organic matter. Inhibiting this requires reducing organic matter, supplying oxygen, or raising the pH. ” Therefore, in order to prevent the generation of hydrogen sulfide, it is necessary to keep the pH slightly alkaline over a long period of time.

On the Growth Factors of Algae in Closed Freshwater, Iwasita, vol. 234 (1991), right column on page 107, line 26 In column 6 on the left side of page 108, "light, moderate water temperature, nitrogen, phosphorus, minerals and the like are required for the eutrophication of the closed water and the growth of algae. If any of these factors is present, algal growth is inhibited. In other words, algal growth is suggested to be suppressed by lowering phosphorus concentrations. ” In addition, Iwashita "Gypsum and Lime" Volume 234 (1991), p. 108 In line 4, the results of the algae inhibitory effect using the substance containing magnesium hydroxide are reported to be "all the inhibitory effect except the heavy calcium carbonate is recognized." Thus, there is a need for an improving agent that reacts with phosphorus to form poorly soluble compounds. There is a need for an improving agent for forming poorly soluble compounds of the magnesium compound type. Magnesium compound type poorly soluble compounds include magnesium phosphate and magnesium ammonium phosphate.

Matsumura also referred to "Gypsum and Lime," Vol. 229 (1990), left column on page 111, on the purification of freshwater. In the right column, line 4, "Ammonia nitrogen eluted by decomposition of organic matter in the scavenger is converted into nitrate nitrogen by dissolved oxygen. When dissolved oxygen in water is consumed, it exists as ammonia nitrogen. The nitrogen in the water is mostly dissolved as ammonium gas toxic to ammonium ions or fish, and the reaction of NH ₄ ⁺ NH ₃ ⁺ H ⁺ is equilibrated between pH 7 to 12, and the higher the pH, the more it shifts to the right side. It is reported. Therefore, in order to reduce the ammonia gas dissolved concentration which is toxic to fish, it is necessary to keep it slightly alkaline and to give off.

Fuetaya et al., "Lime", "Water Lime" in Freshwater Fish Culture and Aquaculture Water pH 419 (1990), page 5 8 In line 10, `` When water phenomena occur, PH 9.5 even in hardness 7.9, pH 7.1 It decreases in 7.4, too. " Therefore, it is necessary to keep the pH of the water quality slightly alkaline even in freshwater fish farming.

50 ppm underwater Since carbonate ions are present in the range of 90 ppm, the slaked lime is carbonated to form calcium carbonate. Iwasita, Shimo or "Gypsum and Lime," Volume 234 (1991), left column on page 109 Line 10 reports that lime sprayed in water reacts with carbon dioxide and gradually changes to calcium carbonate and is completed in one to two months. See also Simon or "lime," 417 (1990), p. 21. In line 21, `` So far, the quick-lime applied to the sea is replaced with magnesium ions in the seawater, and it becomes magnesium hydroxide, but in reality, part of the lime applied is reacted with CO ₂ in the seawater to react with calcium carbonate (aragonite It becomes.

Regarding the reactivity of lime, Japanese Patent Application Laid-Open No. 4-200788 points out that "the reactivity between calcium ions and carbonate ions is greater than the reactivity between calcium ions and phosphate ions," and the reactivity of carbonation in water is extremely high. Is indicated. Therefore, the lime improver has a disadvantage of producing calcium carbonate as a by-product because the reaction with carbonate ions proceeds. As a result, since the surface of the hydroxide is coated with carbonate, the pH retention effect and the reactivity to form the poorly soluble compound are lost.

Since slaked lime has higher solubility than magnesium compounds, the indicated pH at the time of in water has a high characteristic. Therefore, when the improver is administered in water, the pH retention effect expected from the improver is also important, but it is necessary to consider the variation in the pH of the environmental water rising by the administration. Especially in freshwater system with small pH buffering capacity, it needs to be administered carefully. Takashima et al., "Advanced Techniques for Purifying Environmental Water and Water Treatment Technology" (1994), p. 61. Line 22 points out that "in lime administration, the pH is significant and the amount of addition needs to be reviewed." In general, when the hydroxide is administered to the body of water, it is necessary to pay attention because the excessive effect of the pH increases the effect of pH.

Lime sparging is the cheapest and most effective way to improve water quality and low quality environments. The effect is achieved by keeping the water quality and the low quality environment slightly alkaline. However, the lime improver is a strong alkali, and care must be taken in handling such as exothermic heat by reaction with water, that the pH retention effect and the poorly soluble compound formation reaction are not sustained by the progress of the carbonation reaction. There are problems such as a large number of pH fluctuation factors for the water. Therefore, in order to improve the water quality and the quality of the water, there is a need for an inexpensive improver that is safe for the environment and workers and maintains slightly alkaline over a long period of time.

Therefore, the present inventors have intensively researched and solved the above problems and provided a cheap and effective water and low quality magnesium compound-based improving agent which can be used in the pharmaceutical spraying method.

Another object of the present invention is to provide a range of composition and material properties for water and low quality magnesium compound-based improving agent.

Still other objects and advantages of the present invention will become apparent from the following description.

According to the present invention, the above objects and advantages of the present invention provide at least 30 wt% of at least one magnesium compound-based powder in terms of MgO. Containing 20 Moisture Content A water quality or a low quality magnesium compound type | system | group improvement agent characterized by self-decomposing by the addition in water below.

As a magnesium compound type granular material, the granular material of magnesium hydroxide, magnesium oxide, magnesite, or dolomite is mentioned as a preferable thing, for example.

Content of magnesium compound powder is 30 weight in MgO conversion In the lesser case, the effect of maintaining pH in water quality and water quality is not achieved efficiently, and an increase in the amount of input of the modifier is required, which is not preferable. Therefore, MgO conversion content of magnesium compound powder is 30 weight The above is preferable, Furthermore, 30 70 weight The range of is more preferable. Moisture content is 20 weight In the above case, it becomes difficult to form a shape like granules, which is not preferable. Thus the moisture content is 20 weight The following is preferable. Moreover, since the improvement agent of this invention is a magnesium compound type, it has the characteristic that there is no phenomenon of the loss of the effect by advancing of the carbonation reaction seen in a lime system.

The improver of the present invention self-collapses after being introduced into water. By disintegrating in water and dispersing and dissolving, weak alkalinity is exhibited and the weak alkalinity is sustained over a long period, and the improvement effect is advantageously obtained.

The disintegration of the modifiers is largely dependent on the bulk density. The improver added to the water starts to collapse by entering water into the pores mainly by capillary action. The degree of distribution of the pores can be grasped indirectly by measuring the bulk density of the improver. When the bulk density of the improver is 2.3 g / cm 3 or more, since high-strength granules are formed, the disintegration and dispersibility in water decrease, while the cost increases, and it is not economical. Therefore, the bulk density is preferably 2.2 g / cm 3 or less, and 1.0 g / cm 3 More preferred is 1.9 g / cm 3.

The dispersibility of the improver is largely dependent on the particle size of the granules constituting the improver. When the particle diameter of the particles is smaller than 5 m, the particles are easily diffused by water flow, and smoke is likely to occur. Moreover, when larger than 100 m, since the dispersion | distribution range after collapse | stretching becomes narrow and reactivity falls, it is unpreferable since the increase of input amount is needed. Therefore, the average particle diameter of the granular material is 5 The range of 100 m is preferred.

The solubility of the modifier is largely dependent on the specific surface area. When the specific surface area is smaller than 5 m 2 / g, the solubility is lowered, so that the indicated pH is lowered, which is not preferable. Therefore, the specific surface area is preferably 5 m 2 / g or more, 5 The range of 50 m <2> / g is more preferable.

The presence of water soluble magnesium salts expresses the bindery effect in shaping the granules. Moreover, since water solubility magnesium salt has high solubility, when it is thrown in water, the disintegration property of a improver is promoted. Examples of the water-soluble magnesium salts include magnesium chloride, magnesium sulfate, magnesium nitrate and the like. In this exception, any water-soluble magnesium compound can be used.

When expecting the effect of formability of the granules, the presence of the water-soluble magnesium salt is 0.01% by weight. The above is preferable. 5 weight As mentioned above, since a water-soluble magnesium salt hardens on the surface of the shape | molding improvement agent, it exists in the tendency to reduce the disintegration property in water. Therefore, the preferable content range of water-soluble magnesium salt is 0.01 5 weight to be.

By setting the above range, it is easy to handle as a improver, there is little pH fluctuation with respect to environmental water, it has a pH maintenance effect over a long term, and it is possible to provide a cheap improver.

In addition, the measured values of the particle diameter, the specific surface area of the granular material, the pore volume and the bulk density of the improver described in the main text were measured by the following methods.

Particle diameter: measured by JSF-T-131 standard.

Specific surface area: Measured by BET specific surface area 1 point method by nitrogen adsorption method.

Pore volume: Measured by mercury porosimetry by mercury porosimetry.

Bulk density: measured by Archimedes method using kerosene as a medium.

Example 1 5]

Using magnesium hydroxide granules and magnesium oxide granules, ten pieces of five almond-like (20 x 40 mm) granules having different bulk densities shown in Table 1 were prepared by briquette machines. This was uniformly paralleled on a 2000 micrometer sieve, and it left still in a 10 L container. Water was not poured directly onto the assembly, and water was poured until the assembly sank. After standing for 24 hours, the state of the collapsed granules and the state of the supernatant (smoked) were observed. The results are shown in Table 2. The granules started to disintegrate with the release of air in the granules as they were put in water. The supernatant was slightly cloudy at the start of decay, but the clarity of the liquid level was maintained by the sedimentation and melting of the fine particles.

*: Measured by mercury porosimetry

**: collapsed state ○: collapsed without leaving any form of granulated material

(Triangle | delta): It maintains some circular shape.

X: It maintains a nearly circular shape.

***: Supervision status ○: Clarification status (SS 20ppm)

△: very slightly cloudy (SS 40 ppm)

X: It is cloudy.

Example 6

The water tank (450 × 250 × 250) was laid with a headro of a shrimp farm to a thickness of 50 mm, and 12 young shrimps of prawns were filled with seawater. The improvement agent of Example 2 was used as a magnesium compound type improvement agent, and it administered at the ratio of 400 g / m <2> with respect to the tank area. In addition, seawater was changed to 10% of the electrolyzed water once every 3 days, and the pH trend and the growth of prawns were observed. The results of the pH trends are shown in Table 3. It was confirmed that the magnesium compound-based improving agent had a pH of 8.45 even after 90 days of addition, and had no carbonation reaction and had a pH retention effect over a long period of time. It was confirmed that the prawns placed in the water tank were repeatedly stripped, and that the magnesium compound-based improving agent had no fish toxicity.

Example 7

A head furnace collected from a domestic drainage groove where green powder was generated in a 3 l beaker filled with tap water was laid on the front of 20 mm, and the occurrence of green powder was added when the improving agent of Example 2 was added at a rate of 100 g / m 2. In the beaker containing a magnesium compound type | system | group improvement agent, generation | occurrence | production of green powder was not seen but the growth of diatoms was seen. After 16 days, the change of the perspective view by the perspective meter stopped as the perspective view 50cm immediately after adding the improver fell to 48cm.

Comparative Example 1 2]

In the same prawn-filled tank of Example 6, instead of the magnesium compound-based improving agent, a lime-based improving agent and a tank without an improving agent were prepared, and pH transition and growth process of the prawn were observed. In addition, once every three days, seawater replaced 10% of the electrolyzed water. The results of the pH trends are shown in Table 4. The lime system of the comparative example 1 fell to the vicinity of no addition seawater pH on the 30th day after addition. The mineral composition of the lime improver after 30 days was analyzed by X-ray diffraction, and the progress of the carbonation reaction was confirmed by a mixture of calcium carbonate (calcite, aragonite), calcium hydroxide and magnesium hydroxide. The prawns in the tank were grown repeatedly by molting.

Comparative Example 3

A head furnace collected from a household drainage groove where green powder was generated in a 3 l beaker filled with tap water was laid on the entire surface of 20 mm, and the occurrence of green powder was observed without adding an improving agent. Laver powder was generated in the beaker from the 3rd day of observation. After 16 days, the change in perspective with a perspective meter decreased from 50 cm at the start to 25 cm.

[Reference Example]

The settling velocity of the dispersed particles collapsed in Example 2 was 1.8 m / h. Quicklime was then added to the seawater to produce new magnesium. This newborn magnesium was aliquoted and added to the water bath at the ratio of Example 2, and the tank was cloudy. The sedimentation rate of this new magnesium measured by the settler tube is 8 × 10 m / h. From the above results, it can be seen that the new magnesium produced in the lime system has a problem of smoking and is not suitable as a modifier.

As described above, by administering the improver of the present invention to deteriorated water quality and water quality, self-disintegration and dissolution of the improver can be continued for a long time, and the water quality and water quality can be kept slightly alkaline. By keeping it slightly alkaline, the following effects are obtained.

1) It is possible to suppress the growth of sulfate-reducing bacteria as a source of hydrogen sulfide in low quality and to prevent the death by hydrogen sulfide.

2) Ammonium ions generated by decay of organic matter can be equilibrated to ammonia gas, and atmospheric diffusion due to aeration is likely to proceed.

3) Inhibition of sanding by acidification of cultured water quality.

4) Furthermore, by forming a phosphorus and a poorly water-soluble compound in the water quality, the phosphorus concentration can be reduced, and abnormal growth of the green powder can be prevented.

Claims (5)

30 weights of one or more magnesium compound powders in terms of MgO It contains more than 20 moisture content The water quality or low magnesium compound type improvement agent characterized by the above-mentioned, and self-decomposing by the addition of in water. The magnesium compound-based improving agent according to claim 1, wherein the magnesium compound-based powder is a powder of magnesium hydroxide, magnesium oxide, magnesite or dolomite. The method of claim 1, wherein the magnesium compound powder is 5 Magnesium compound type improver which has an average particle diameter of 100 micrometers. The magnesium compound-based improving agent according to claim 1, wherein the magnesium compound-based powder has a bulk density of 2.2 g / cm 3 or less. The water-soluble magnesium salt of claim 1 is separated from the magnesium compound powder. 5 weight A magnesium compound-based improving agent contained in the amount of.