JPS6236758B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to novel calcium-containing compositions for use in water treatment. More specifically, the present invention proposes a calcium-containing composition that has the property of being able to supply water with the appropriate amount of calcium required for a long period of time in a desirable state.
As is well known, in the field of water treatment, techniques such as chemical treatment methods, ion exchange methods, reverse osmosis methods, and steam methods are implemented on an industrial scale to obtain water of the required quality. Depending on the technical treatment method, especially when used as drinking water, mineral components may be lacking, so a small amount of calcium, which is a hardness component, is added to the treated water to add flavor and remove odor components. ing. The present inventor is currently conducting extensive research into calcium-containing compositions that have properties that are optimal for the purpose of use. It is suitable for the purpose of injecting calcium, and furthermore, the calcium-containing composition, which is mainly composed of a ternary calcined body of calcium carbonate, zeolite, and activated carbon, is suitable not only for injecting calcium into water, but also for eliminating odor components in water. The present invention was achieved by discovering that this method is also effective in removing COD contributing substances. The details of the invention are described below. The first aspect of the present invention is to provide a calcium-containing composition for the purpose of calcium injection, which is mainly composed of a calcined body of calcium carbonate-zeolite. The calcium carbonate and zeolite used here are powders.
Preferably, the mixture is in the form of particles, and the mixture is wet-mixed in the presence of an inorganic and/or organic binder, formed into pellets, tablets, spheres, etc., and then dried. The obtained dried product is then calcined at a temperature below the decomposition temperature of calcium carbonate and zeolite to obtain a calcium-containing composition with high compressive strength. Zeolite, which is one of the components constituting the composition of the present invention, is an aluminosilicate having a three-dimensional skeleton structure and is represented by the general formula XM2/nO.Al ₂ O ₃ ySiO _{2.ZH 2} O . M represents an ion-exchangeable metal, and is usually a mono- or divalent metal. In addition, n represents the valence of the metal, and X and y represent the coefficients of metal oxide and silica, respectively.
Z represents water of crystallization. In the present invention,
As the zeolite material, synthetic zeolites such as A-type zeolite, X-type zeolite, Y-type zeolite, and mordenite can be used.
On the other hand, natural zeolites such as 1010A (clinoptilolite), 2020A (mordenite), and 5050L (chabazite) from Anaconda (USA) are also used as the zeolite of the present invention. Suitable as a material. In addition to the above, domestically produced natural zeolites are also suitable as materials for the present invention.
The above synthetic zeolites and natural zeolites can be commercially available in the form of powder or particles and used as the zeolite material of the present invention, but they can be further treated with calcium salts (e.g. CaCl ₂ , Ca(NO ₃ ) ₂ ). ,
It is more desirable as a material that M in the above general formula is converted to the calcium type as much as possible by performing ion exchange at room temperature or constant temperature. In other words, by using a calcium composition in which calcium carbonate is combined with zeolite enriched with calcium through the latter salt treatment, there is an advantage that calcium injection into water can be carried out effectively for a longer period of time. be. In order to obtain the calcium-containing composition of the present invention, the molded dry body is fired, and as described above, the temperature is specified to be below the decomposition temperature of calcium carbonate and biolite. This is based on the following reasons. Calcium carbonate decomposes to CaO at around 825℃.
and generates CO ₂ gas. Therefore, the use of such high temperatures is inappropriate because it causes decomposition of the calcium carbonate material. Moreover, the above-mentioned zeolite used in the present invention is not preferable at the above-mentioned temperature because it causes structural destruction and performance deterioration. In general, a temperature range of 450 DEG to 650 DEG C. is a preferred range for obtaining the fired body of the calcium-containing composition of the present invention, which has excellent mechanical strength. The weight ratio of zeolite (z) to calcium carbonate (c) in the calcined calcium-containing composition of the present invention is suitably in the range of Z/C = 0.25 to 4, and this ratio depends on the quality of water required. Determined accordingly. The amount of organic and/or inorganic binder added to the mixture of calcium carbonate and zeolite to adjust the calcium-containing composition of the present invention is suitably 5 to 30% based on the mixture. When the calcium-containing composition of the present invention comes into contact with water, CaCO ₃ , one of the main components, gradually dissolves in a very small amount (the solubility of CaCO ₃ is 15 to 15% at room temperature).
(reaches 20ppm). It also reacts with carbon dioxide in the water to form a more soluble bicarbonate [CaCO _{3 ]} .
+CO ₂ +H ₂ O→Ca(HCO ₃ ) ₂ ] is generated.
Ca ²⁺ has the advantage of being continuously injected into water in minute amounts under favorable conditions. Furthermore, the metal bonded to the ion-exchangeable zeolite, which is one of the main components in the composition, is gradually exchanged with trace components dissolved in the water, and is eluted into the water in trace amounts. In this case, it is better to use a calcium-enriched zeolite material treated with calcium salts as described above.
It was confirmed that the effect of supplying a small amount of Ca ²⁺ smoothly and continuously over a long period of time was confirmed. The second aspect of the present invention is to provide a calcium-containing composition for the purpose of calcium injection, which is mainly composed of a calcined body of calcium carbonate, zeolite, and activated carbon. The present invention provides a first calcium carbonate-zeolite-based 2
Activated carbon is added to a ternary composition to form a ternary composition. The use of such a ternary composition has the advantage that, in addition to the effect of injecting calcium into water as described in the first invention, it also has the added effect of removing odor components in water and organic components that contribute to COD. The calcium carbonate-zeolite-activated carbon-containing composition may be prepared according to the first method of the present invention. However, the calcination of the above ternary composition of the present invention must be carried out at a temperature below the decomposition temperature of the constituent calcium carbonate and zeolite, and either with the exclusion of air or in an inert gas atmosphere (see Examples below). be. This method can prevent loss of activated carbon, which is one of the components. Zeolite (z) and calcium carbonate (c) in the calcined calcium-containing composition of the present invention
Total amount and weight ratio of activated carbon (a) (Z + C) / a = 0.5
A range of ~4 is appropriate, while the weight ratio of Z/C is
A desirable range is 0.3 to 4. Note that 3 of the present invention
The amount of organic and/or inorganic binder added to the mixture of calcium carbonate, zeolite and activated carbon in order to prepare the original calcium-containing composition by a wet method is 7% based on the mixture.
~32% is appropriate. The third invention relates to the first invention, which is a method for producing a calcium-containing composition mainly composed of a calcined body of calcium carbonate-zeolite.
That is, the present invention involves adding an inorganic and/or organic binder to a mixture of calcium carbonate and zeolite, performing wet mixing in the presence of water, molding the resulting mixture, and then molding the resulting mixture. This describes a method for producing a calcium-containing composition, which is characterized in that the dried product is dried at a temperature below the temperature at which calcium carbonate starts to decompose. As mentioned above, the calcium carbonate used as the material of the present invention is suitably in a powder to particulate state, and a powder of 100 to 200 meshes is particularly suitable.On the other hand, as the zeolite material, the above-mentioned natural or synthetic zeolite is a powder. ~Used in particulate form. Also suitable as a material are zeolites obtained by treating the above natural or synthetic zeolites with calcium salts and performing ion exchange to enrich calcium. If necessary, the calcium-enriched zeolite described above is pulverized and used as one of the main components of the present invention in the form of powder to coarse particles.
Zeolite particles that exhibit the same particle size distribution as the above-mentioned calcium carbonate material are desirable in order to obtain a uniform composite of these. Now, the above two types of materials are wet-kneaded in a mixer by adding water or urea aqueous solution in the presence of an inorganic and/or organic binder, and then formed into shapes such as pellets, doublets, and spheres. Ru.
During wet mixing, a water ratio of 19 to 35% is appropriate to obtain a homogeneous material that is easy to mold. On the other hand, as the binder, the following binders are preferred for obtaining the composition of the present invention. Examples of inorganic binders include bentonite, kaolin, diatomaceous earth, water glass, colloidal silica, and colloidal alumina, while organic binders include methyl cellulose, carboxymethyl cellulose,
Examples include crystalline cellulose compounds such as hydroxyethyl cellulose and hydroxypropyl cellulose, molasses, sodium lignin sulfonate, calcium lignin sulfonate, polyvinyl alcohol, acrylic ester, and phenolic resin. These organic and inorganic binders may be used alone or in combination. The appropriate amount of the binder used is 5 to 30% based on the dry product of the calcium carbonate and zeolite mixture. The calcium carbonate-zeolite composite formed into a predetermined shape through this mixing process is usually dried at 100° to 110°C and then adjusted to have a certain shape distribution.
The prepared dry molded product is fired in a temperature range below the decomposition temperature of calcium carbonate and zeolite to obtain the calcium-containing composition of the present invention.
The firing temperature range for the above composition is suitably 400° to 620°C, with 450° to 600°C being the most preferred range. The calcium-containing composition of the present invention obtained by such a molding method has extremely high mechanical strength, and calcium can be injected into water in a favorable manner, as will be clear from the examples described below. The fourth invention relates to the second invention, which is a method for producing a calcium-containing composition mainly composed of a calcined body of calcium carbonate, zeolite, and activated carbon. As the calcium carbonate and zeolite used as the main component materials, the materials used in the third invention can be applied as they are. The activated carbon used as one of the main components of the present invention may be coconut shell activated carbon or carbonaceous activated carbon, and is used in the form of powder to coarse particles. On the other hand, the same inorganic and/or organic binders as mentioned in the third invention can be used as subcomponents in wet molding. The appropriate amount of this addition is 7 to 32%. In addition, a moisture content of 24 to 41% during wet mixing is suitable for obtaining a homogeneous material mixture that is easy to mold. The molded body formed into a certain shape by the wet method is dried and finally fired to increase the mechanical strength of the molded body. In this case, the calcination process is performed at a temperature below the decomposition temperature of calcium carbonate and zeolite, which are the main components of the composition, and in order to prevent loss of activated carbon, air is shut off or an inert gas such as nitrogen or carbon dioxide is used. Must be carried out in a gas atmosphere. A suitable firing temperature range is 400° to 620°C. Next, embodiments of the present invention will be described with reference to Examples, but the present invention is not limited to these Examples unless the gist thereof is exceeded. <Example 1> This example relates to a method for producing the calcium-containing composition of the first invention, which is mainly composed of a calcined body of calcium carbonate-zeolite and is intended for calcium injection. As raw materials, 4.0 kg of natural clinoptilolite powder of 100 to 200 mesh [Anaconda (USA) 1010A clinoptilolite] and 4.0 kg of calcium carbonate powder of 100 to 200 mesh were used. To this was added 2.4 kg of bentonite powder of 100 to 200 meshes as an inorganic binder and mixed using a mixer. Next, water was added to the mixed powder and kneaded using a mixer. During kneading, the moisture content is
The content was maintained at 24.1%, and the kneading time was 3 hours and 30 minutes. The mixture obtained by the above process was molded into 1/16" (0.16 cm) pellets using a twin-screw molding machine, and subsequently dried at 100° to 110°C. Next, 1/6" (0.16 cm) The length of the dried pellets was adjusted using a flasher, and the length of the pellets was in the range of 2.5 mm to 5.5 mm, and dried pellets with an average length of 3.9 mm were prepared. The dried pellets were finally calcined in an air oven (air atmosphere) at 550 DEG -560 DEG C. for about 4 hours to obtain the desired calcium-containing composition. Table 1 shows the compressive strengths of the dried and fired 1/16" (0.16 cm) pellets obtained in this example. The values in the table are the results measured by sampling tests. The maximum and minimum compressive strength values were excluded when calculating the average value (c).

[Table] As is clear from the table, the compressive strength of the calcined calcium-containing composition of the present invention is extremely high, reaching 8.95 kg/pellet. A calcium-containing composition having such a value has the advantage that the pellets are stably maintained without being broken or losing their shape when added to water, and gradually release calcium into the water. <Example 2> This example relates to the production of the calcium-containing composition of the first invention, which is mainly composed of a calcium carbonate-calcium type zeolite fired body and is intended for calcium injection. The zeolite material used in this example was a synthetic A-type zeolite powder (sodium type) treated with an excess calcium chloride solution to convert it into a calcium type. That is, 1.02Na ₂ O・Al ₂ O ₃・1.95SiO ₂・XH ₂ O
A-type zeolite powder with a chemical composition of
Most of the ion-exchangeable sodium was converted to calcium form by treatment with 1.5 MCaCl ₂ solution.
A calcium- _enriched A _{- type} zeolite _powder having a composition of _{0.06Na20.0.96CaO.Al2O3.1.95SiO2.XH2O} was obtained. Using this as a zeolite material, the calcium carbonate-calcium type zeolite composition of the present invention (1/16" (0.16 cm) pellets)
was prepared. <Preparation conditions for the composition of Example 2> Raw material: (a) Dry powder of calcium-substituted type A zeolite (100 to 200 mesh;
0.06Na ₂ 0・0.96CaO・Al ₂ O ₃・
1.95SiO ₂・XH ₂ O): 2.31Kg (b) Calcium carbonate dry powder (100~
200 mesh): 0.68Kg Binder: Bentonite fine powder: 480g [16.1% added to (a+b) above] Moisture content during mixing: 30.9% Mixing time: 3 hours 30 minutes Molding: 1/16″ (0.16 cm) Pellet Drying temperature of pellets: 100° to 110°C Calcining of pellets: 540° to 550°C (4 hours 40 minutes; air atmosphere) The composition of the present invention obtained under the above preparation conditions is listed in Table 2. It has favorable strength such as

[Table] <Example 3> This example mainly uses calcium carbonate-zeolite-
The present invention relates to a method for producing a calcium-containing composition according to the second invention, which is intended for injecting calcium into water made of a fired body of activated carbon. The raw material is 713g of dry powder of natural clinoptilolite zeolite weighing 100 to 200 meshes.
[Anaconda (USA) 1010A
(clinoptilolite)] and 100~
A mixed powder of these was prepared using 285 g of 200 mesh dry powder of calcium carbonate and 428 g of dry powder of activated carbon (coconut shell activated carbon) of 100 to 200 mesh. To the mixed powder containing the above three materials, 21% of dried fine bentonite powder was added as an inorganic binder, and 2% of methylcellulose (commercially available methylcellulose) was added as an organic binder.
Viscosity of aqueous solution at 20℃ = 7.000-10.000cps)
Add 1% of
I went to work. The moisture content during mixing was adjusted to 34-35%. The mixture obtained in the above method was molded into 1/8″ (0.32 cm) pellets using a twin-screw molding machine, and then
The molded product was dried at 100° to 110°C. Next, the length of the obtained 1/8″ (0.32 cm) dried pellets was adjusted using a flasher, and the length of the pellets was within the range of 2.7 mm to 5.6 mm, with an average length of
3.9 dry pellets were prepared. Next, the adjusted 1/8″ (0.32cm) dried pellets are finally heated to 540° to 550°C (nitrogen gas atmosphere) in an electric furnace for about 40 minutes.
It was fired for 30 minutes to obtain the desired ternary calcium-containing composition. The compressive strength values of the dried and fired 1/8″ (0.32 cm) pellets obtained in this example were
Shown in the table. The values in the table show the measured results of sampling tests, and the maximum and minimum values of compressive strength were excluded when calculating the average value (c).

[Table] As is clear from the table, the compressive strength of the ternary calcium-containing composition (calcined) of the present invention is extremely high, reaching c=14.7 kg/pellet. Calcium-containing compositions with such values are extremely stable even when immersed in water, and maintain their pellet shape for a long period of time while gradually releasing calcium into the water and removing odor components and COD substances from the water. It was confirmed that there is an effect. <Example 4> This example relates to the production of the calcium-containing composition of the first invention, which is mainly composed of calcium carbonate-calcium type zeolite (natural product) and is intended for calcium injection. In this example, natural clinoptilolite was ion-exchanged to increase the calcium content in the zeolite, and a composite of this and calcium carbonate was fabricated. Natural clinoptilolite [Anaconda (USA), 1010A (Clinoptilolite): Ca
= 0.76% (anhydrous standard)] to 1.0 kg of fine powder
1.4MCaCl ₂ -solution 2.0 was added and the resulting mixture was kept under stirring at 60°-70°C for 2 hours. After the reaction was completed, the solid phase and liquid phase were separated. For the solid phase, exactly the same batch procedure as described above was performed again. This treatment with calcium chloride solution was carried out a total of four times. The treated zeolite phase was filtered and washed with warm water. In this case, water washing was carried out until chlorine ions were removed. Treated zeolite (Ca=
2.54% (anhydrous standard)] after drying at 100° to 110°C,
It was used as one of the molding materials of the present invention. Preparation conditions for the composition of Example 4-4 Raw materials: (a) Calcium-substituted natural clinoptilolite dry powder (100-200 mesh): 765 g (b) Calcium carbonate dry powder (100-200 mesh): 765g Binder: Fine bentonite powder: 460g Moisture content during mixing: 23% Mixing time: 2 hours 20 minutes Molding: 1/16″ (0.16cm) pellets Drying temperature of pellets: 100° to 110°C Calcining of pellets: 540° ~550°C (3 hours and 10 minutes) The composition of the present invention obtained by the above-mentioned wet molding had extremely high strength as shown in Table 4, with an average value of 11.27 kg/pellet. When calculating, the maximum and minimum values in the table were excluded.

[Table] <Example 5> This example shows that when the calcium-containing composition of the present invention is immersed in water, a trace amount of calcium in the composition is easily released into the water. . 18 g (1/16" (0.16 cm) pellets; = 8.95 Kg/pellet) of the calcium-containing composition of the present invention obtained in Example-1 was collected in a beaker, 1 portion of pure water was added thereto, and the mixture was heated at room temperature. Continuous stirring was carried out at 150 rpm.As another test, 29 g (1/16" (0.16 cm) pellets of the calcium-containing composition of the present invention obtained in Example-4); = 11.27
Kg/pellet) was collected in a beaker, 1 portion of pure water was added thereto, and continuous stirring was performed at 150 rpm at room temperature in the same manner as above. After a certain period of time had elapsed, a portion of the aqueous solution phase was sampled and the dissolved calcium concentration was measured by atomic absorption spectrometry to obtain the results shown in Table 5.

[Table] From these two calcium withdrawal tests, it is clear that the calcium component in the present composition is dissolved and transferred to water in a very small amount in a desirable manner. Moreover, throughout the test, no disintegration of the calcium-containing composition formed into pellets was observed, and it was found that the micro-injection of calcium into water could be ideally carried out over a long period of time. <Example 6> This example relates to a test of dissolved calcium in the liquid flowing out from the bed by constructing a packed bed made of the calcium-containing composition of the present invention and passing water through the bed. That is, the calcium-containing composition of the present invention obtained from Example-1 (1/16" (0.16 cm)
Approximately 90g of pellets (=8.95Kg/pellet) was packed into a glass column to create an adsorption bed [22mm (inner diameter) x
240 mm (height)], through which demineralized water purified by ion exchange was passed at a flow rate of 8 to 10 ml/min. At this time, the effluent from the bottom of the adsorption tower was sampled at regular intervals, and the calcium concentration therein was measured by atomic absorption spectrometry, and the results shown in Table 6 were obtained.

【table】

Claims (1)

[Scope of Claims] 1. A calcium-containing composition for water treatment for the purpose of calcium injection, the main component of which is a calcined body of a calcium carbonate-zeolite binary composition. 2. The calcium-containing composition for water treatment according to claim 1, which includes activated carbon added to a calcium carbonate-zeolite binary system. 3 Wet mixing is carried out in the presence of water with the addition of inorganic and/or organic binders to the mixture of calcium carbonate and zeolite, and the resulting mixture is shaped and subsequently dried before final production. 1. A method for producing a calcium-containing composition for water treatment, which comprises firing at a temperature below the start of thermal decomposition of calcium carbonate and below the decomposition temperature of zeolite. 4. The method for producing a calcium-containing composition for water treatment according to claim 3, wherein a mixture of calcium carbonate, zeolite, and activated carbon is used, and calcination is performed under air exclusion or an inert gas atmosphere.