JPH09174045A - Agent for removing phosphate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an agent for removing phosphates with a higher adsorption coefficient by kneading calcium carbonate, a magnesium-containing mineral immersed in a diluted sulfuric acid, a porous material for increasing the specific surface area, and a binder and forming the resultant mixture into granular bodies. SOLUTION: Calcium carbonate, a magnesium-containing mineral, a porous material for increasing the specific surface area, and a binder, which are respectively formed into powder granules are prepared and at first the powder granules of the magnesium- containing mineral are immersed in a diluted sulfuric acid to give a slurry and the other components are added to the resultant slurry and kneaded for a proper time, and then the resultant mixture is granulated into a proper size, for example about 2-3cm, using a granulating apparatus. Consequently, calcium derived from calcium carbonate is gradually dissolved as calcium sulfate due to the diluted sulfuric acid used for the treatment of the magnesiumcontaining mineral and also magnesium derived from the magnesium-containing mineral is gradually dissolved as magnesium sulfate and the calcium and the magnesium are reacted with pyrophosphoric acid and metaphosphoric acid, so that phosphates in water are made insoluble and phosphates are removed and consequently high efficiency of the removal of the phosphates can be achieved.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a dephosphorizing agent used for dephosphorization in water purification.

[0002]

2. Description of the Related Art For dephosphorization in water purification, for example, a method using a flocculant, a method by biological treatment, or a method using a dephosphorizing agent by adsorption is known.
It goes without saying that the efficiency of the dephosphorizing method among these can be increased as the absorption coefficient of phosphorus of the dephosphorizing agent used therein increases. In other words, the efficiency of the dephosphorization treatment in this method is determined by how the dephosphorizing agent having a large absorption coefficient can be obtained.

[0003]

SUMMARY OF THE INVENTION The present invention is obtained by the research conducted from such a viewpoint, and an object thereof is to provide a dephosphorizing agent having a larger absorption coefficient.

[0004]

The dephosphorizing agent according to the present invention is made into a granular form by kneading calcium carbonate, a magnesium-containing mineral immersed in dilute sulfuric acid, a porous material for increasing the specific surface area, and a binder. Formed.

This dephosphorizing agent has a higher absorption coefficient than conventionally used dephosphorizing agents, and the main reasons are considered as follows. That is, with the dilute sulfuric acid used for the treatment of the magnesium-containing mineral, calcium from calcium carbonate is gradually eluted as calcium sulfate, and magnesium from the magnesium-containing mineral is gradually eluted as magnesium sulfate. By reacting to form calcium phosphate, calcium hydrogen phosphate, magnesium phosphate, magnesium hydrogen phosphate, etc., to insolubilize the phosphorus content in the water to achieve dephosphorization, and by such dephosphorization action, high dephosphorization efficiency is realized. it can.

With respect to such a dephosphorizing agent, if a porous material having pores suitable for organic substances and microorganisms suitable for assimilation of microorganisms is further added, the above chemical dephosphorizing action is obtained. In addition to this, a biological dephosphorization effect can be utilized, and the dephosphorization efficiency can be further enhanced.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION In the first embodiment of the present invention, calcium carbonate and magnesium-containing minerals, which are each made into powder and granules,
Prepare a porous material for increasing the specific surface area, and a binder, first dip magnesium-containing mineral powder in dilute sulfuric acid to form a slurry, and add the above-mentioned other components to this and knead for a suitable time, Then, using a granulator or the like, for example, 2-3 c
The particle size is about m. Although the final product can be used as it is, it may be naturally dried if necessary and dried by an appropriate dryer.

As the magnesium-containing mineral, various minerals can be used, but it is particularly preferable to use serpentine.
Vermiculite or zeolite is preferably used as the porous material for increasing the specific surface area, and these are usually used in combination. Further, it is preferable to use cement (Portland cement) as the binder.

In the second embodiment of the present invention, an organic material suitable for assimilation of microorganisms and a porous material having pores suitable for breeding of microorganisms are further added to the component constitution of the first embodiment. As an organic matter suitable for assimilation of microorganisms, those containing a large amount of polysaccharides, for example, it is preferable to use wood fibers such as agar and pulp together, in this case, the polysaccharides elute calcium and magnesium components described above. It can also be used to regulate the rate and increase the long-term stability of the dephosphorization capacity. As the porous material having pores suitable for the propagation of microorganisms, it is preferable to use fir shell or charcoal, and these are usually used together.

[0010]

EXAMPLES The first example is an example corresponding to the above-mentioned first embodiment, and the compounding ratio of each component in this example is as follows: calcium carbonate; 63.89% by weight; sulfuric acid-treated serpentine; 3.84% by weight. , Vermiculite; 0.32% by weight, cement; 31.95
% By weight. The sulfuric acid-treated serpentine was prepared by dissolving 1.2 kg of powdery serpentine per liter in dilute sulfuric acid having a normality of 15. Then mix these and add water appropriately and knead for a suitable time, then average 3 on a granulator.
It was granulated into a spherical shape having a diameter of about cm.

The second embodiment is an example corresponding to the above-mentioned second embodiment, and the mixing ratio of each component in this embodiment is as follows: calcium carbonate; 63.54% by weight; sulfuric acid-treated serpentine; 3.82% by weight; Vermiculite: 0.31% by weight, agar: 0.04% by weight, virgin pulp: 0.23% by weight, fir shell 0.29% by weight,
Cement; 31.77% by weight. The sulfuric acid-treated serpentine is the same as in the first embodiment. Agar and virgin pulp were each dissolved in water before use. In this case, dissolved water of agar and virgin pulp and diluted sulfuric acid were used as water for kneading for an appropriate time, and then granulated with a granulator in the same manner as in Example 1.

The third example is another example corresponding to the above second embodiment, and the compounding ratio of each component in this example is as follows.
Calcium carbonate; 62.12% by weight, sulfuric acid treated serpentine; 3.
74% by weight, vermiculite; 0.31% by weight, agar; 0.04
% By weight, virgin pulp: 0.22% by weight, charcoal: 2.52% by weight, cement: 31.06% by weight. The granulation conditions in this case are the same as those in the second embodiment.

The absorption coefficient of the dephosphorizing agent obtained in each of these examples is about 7,000 milligram equivalent for the dephosphorizing agent according to the first example, and about 10000 mg for the dephosphorizing agent according to the second example. The dephosphorizing agent according to the third example was about 12000 mg equivalent. These absorption coefficients show a significant improvement in the dephosphorization ability as compared with the conventional dephosphorizing agent having a large amount of about 5000 mg.

Claims (7)

[Claims] 1. A dephosphorizing agent formed by kneading calcium carbonate, a magnesium-containing mineral immersed in dilute sulfuric acid, a porous material for increasing the specific surface area, and a binder to form a granular form. 2. An organic substance having an assimilation suitability for microorganisms,
The dephosphorizing agent according to claim 1, further comprising a porous material having pores suitable for propagation of microorganisms. 3. The dephosphorizing agent according to claim 1, wherein serpentine is used as the magnesium-containing mineral. 4. The dephosphorizing agent according to claim 1, wherein vermiculite or zeolite, or vermiculite and zeolite are used as the porous material for increasing the specific surface area. 5. The dephosphorizing agent according to claim 1, wherein cement is used as a binder. 6. The dephosphorizing agent according to claim 2, wherein agar and wood fiber are used as the organic substances having an assimilation suitability for microorganisms. 7. The dephosphorizing agent according to claim 2, wherein fir shell or charcoal or fir shell and charcoal is used as the porous material having pores suitable for propagation of microorganisms.