JP2007238361A - Method for producing iron component-containing artificial zeolite and iron component-containing artificial zeolite - Google Patents

Abstract

[PROBLEMS] To reduce the number of manufacturing steps and the manufacturing cost in a method for manufacturing an iron component-containing artificial zeolite.
The method for producing an artificial zeolite containing an iron component according to the present invention is a method for producing artificial zeolite by mixing waste products such as coal ash or industrial by-products of industrial products with an alkaline aqueous solution such as caustic soda and heating them. In this method, an artificial zeolite containing an iron component is obtained by adding an iron component-containing substance in at least one of the mixing step and the heating reaction step.
[Selection figure] None

Description

  The present invention relates to a method for producing an iron component-containing artificial zeolite containing an iron component, and an iron-containing artificial zeolite obtained by this method.

  Artificial zeolite containing an iron component has the effect of adsorbing heavy metals in soil and water in addition to the water retention effect, the nutrient loading effect in the soil, and the slow release effect of the iron component and the loaded nutrient. It is considered to be used for agriculture, horticulture, concrete blocks, etc.

  As a conventional method for producing an iron component-containing artificial zeolite, there is a method in which coal ash is heated and reacted in caustic soda (NaOH solution) to produce an Na-type artificial zeolite, and then an Fe component such as iron hydroxide is added. (For example, refer to Patent Document 1).

In synthetic zeolite, it is known that Al or Si forming the skeleton of the zeolite can be substituted with other elements. That is, it is disclosed that atoms such as Be, B, Ga, Cr, Fe, Ge, Ti, and P can partially substitute Al or Si forming the skeleton of the zeolite with other elements. . (For example, see Non-Patent Document 1)
Japanese Patent No. 3469468 (Claims) Tomonaga Hiroo “Zeolite Chemistry and Applications” 1987, Kodansha, pp. 96-97

  As a method for producing the above iron component-containing artificial zeolite, for example, coal ash or the like is heated and reacted in an alkaline aqueous solution such as caustic soda (NaOH solution) to produce Na type artificial zeolite, and then iron such as iron hydroxide is produced. It was common to add components and introduce iron ions by ion exchange.

  Therefore, when producing a conventional iron-type artificial zeolite, two steps of a zeolite production reaction step and an iron component addition step are required, which increases the number of manufacturing steps and increases the manufacturing cost.

  In addition, when iron ions are introduced into an artificial zeolite by ion exchange as described above, it is necessary to adjust the pH to an appropriate range in order to prevent the zeolite from being dissolved in an acid and to enable ion exchange. is there. However, when slaked lime or the like is added to raise the pH when iron chloride is added as the iron component and the pH is in the above range, iron hydroxide is generated and iron is less likely to be ionized. However, it is very difficult to produce artificial zeolite with a high iron introduction amount in a simple manufacturing process.

  Furthermore, when an iron component-containing artificial zeolite is produced by the above method, there is a problem that iron hydroxide not introduced into the zeolite adheres to the surface, and the resultant artificial zeolite is colored reddish brown or ocher.

  Therefore, the present invention solves the above-mentioned problems, and its problem is to reduce the number of manufacturing steps and the manufacturing cost in the method for manufacturing an iron component-containing artificial zeolite. Another object is to provide an iron component-containing artificial zeolite having a high iron content and a low degree of coloring.

  As a result of intensive studies to solve the above-mentioned problems, the inventors of the present invention produced an iron component-containing substance at the time of mixing or heating reaction with an industrial by-product of waste or industrial products and an alkaline aqueous solution in producing artificial zeolite. By adding, it was found that a high-quality iron component-containing artificial zeolite can be produced without providing the ion exchange step, and the present invention has been completed.

  Moreover, as said iron component containing substance, it is preferable in order to introduce | transduce an iron component efficiently that it is water-soluble iron salts, such as iron chloride, iron hydroxide, iron oxide, iron sulfate, and iron nitrate. In particular, iron chloride is most preferable because it is excellent in solubility, can reduce the manufacturing cost, can shorten the reaction time, and has good reactivity.

  Furthermore, it is preferable to adjust the concentration of an aqueous alkali solution such as caustic soda in the above solution within a range of 0.8 to 5.0 mol / L. When the alkali concentration is lower than the above range, the reactivity of the artificial zeolite is lowered, and when it exceeds the above range, there is a possibility that unreacted parts increase and the economic efficiency is impaired.

  Moreover, it is preferable to adjust the iron component density | concentration in the said solution to 0.15-1.0 mol / L. When the iron component concentration is below the above range, it may not be possible to expect the production of the iron component-containing artificial zeolite. When the iron component concentration is above the above range, it may be an inhibiting factor for the production of the artificial zeolite.

  In the present invention, typically, 100 to 600 parts by weight of water is blended with 100 parts by weight of a main raw material such as waste containing coal ash or the like as a main component or a by-product of an industrial product, and an alkali (for example, Caustic soda) is added to 0.8 to 5.0 mol / L and the iron component (for example, iron chloride) concentration is set to 0.15 to 1.0 mol / L. After mixing and stirring, the mixture is heated to 80 to 180 ° C. And by hold | maintaining about 30 minutes-about 10 hours, the iron component containing type | mold artificial zeolite which has favorable quality can be manufactured efficiently.

  Conventionally, a process for containing an iron component was required after the artificial zeolite reaction process, but the process could be shortened by simultaneously adding the iron component from the beginning. As a result, an iron component-containing artificial zeolite could be produced at a lower cost than before. Further, in the conventional manufacturing method, iron hydroxide or the like adheres to the surface of the artificial zeolite and has a brown to ocher color. According to the present invention, an iron component-containing artificial zeolite that is less colored (light orange) is produced. It became possible to apply to a wide range of fields such as agriculture, horticulture, and concrete blocks.

[Basic manufacturing method and basic structure of artificial zeolite]
The artificial zeolite of the present invention is a by-product of waste or industrial products such as coal ash, paper sludge incinerated ash, aluminum dross residual ash, slag, pearlite, pearlite ore, volcanic ash, shirasu and other volcanic ash deposits and RDF incinerated ash It is obtained by subjecting a material or the like as a main raw material to alkaline hydrothermal treatment. The artificial zeolite of the present invention is preferably obtained from coal ash.

  Natural zeolite has a problem that the price is inexpensive but the quality is not stable. Synthetic zeolite is stable in quality but expensive in price. The artificial zeolite used in the present invention uses waste or industrial product by-products as the main raw material as described above, and therefore can be manufactured at a relatively low cost and has a stable quality. can get.

  Artificial zeolite obtained from the waste or industrial product by-product contains alkali metal ions, but can be ion-exchanged to other metal ions such as alkaline earth metal ions by an ion exchange reaction. it can. For example, by adding artificial zeolite to a calcium salt aqueous solution, stirring, filtering, washing with water, and drying, an artificial zeolite in which a part of alkali metal ions is ion-exchanged with calcium ions can be obtained. The artificial zeolite that can be used in the present invention contains alkali metal ions and / or alkaline earth metal ions and / or iron ions. The alkali metal ion is lithium ion, sodium ion or potassium ion, preferably sodium ion. This alkaline earth metal ion is magnesium ion, calcium ion, strontium ion or barium ion, preferably calcium ion.

[Details of manufacturing method]
In the present invention, an alkaline aqueous solution such as caustic soda whose concentration is adjusted using waste or industrial by-products such as coal ash as main raw materials, and an iron component (additional water may be added if necessary) are mixed. An artificial zeolite production method characterized in that iron component-containing artificial zeolite is produced by heating after stirring.

  Examples of the highly reactive aqueous alkali solution include NaOH solution (caustic soda) and KOH solution. Of these, NaOH solution (caustic soda) is particularly desirable in the production of artificial zeolite.

  Also, an alkaline aqueous solution such as caustic soda with a concentration adjusted from waste or industrial by-products such as coal ash (additional water may be added if necessary) is added, and then iron components are added during the heating reaction. (Iron-containing substance) may be added.

  Further, as the iron component-containing substance, a water-soluble iron salt is preferable for efficiently introducing the iron component, and examples thereof include iron chloride, iron hydroxide, iron oxide, iron sulfate, and iron nitrate. Iron chloride is particularly desirable for shortening and increasing reactivity.

  The mixing ratio of the solution is 100 to 600 parts by weight of water and 100% by weight of alkali such as caustic soda with respect to 100 parts by weight of main raw materials such as waste products such as coal ash or by-products of industrial products. It is desirable to blend -5.0 mol / L and 0.15-1.0 mol / L of the iron component. When the amount of water is 100 parts by weight or less, the product is slurried and there is a problem in conveyance, and when it is 600 parts by weight or more, the economy may be impaired. Further, when the alkali concentration of caustic soda or the like is less than 0.8 mol / L, the reactivity of the artificial zeolite is lowered, and when it is more than 5.0 mol / L, the unreacted portion increases and the economy may be impaired. In addition, when the iron component concentration is less than 0.15 mol / L, the production of the iron component-containing artificial zeolite may not be expected, and when the iron component concentration is more than 1.0 mol / L, it may be an inhibiting factor for the production of the artificial zeolite. is there.

  Moreover, as reaction conditions of the said solution, after mixing and stirring, it is 200 degrees C or less, It is desirable to heat so that it may become in the range of 80-180 degreeC, and it is desirable to hold | maintain this temperature for about 30 minutes-10 hours. If the reaction time is 30 minutes or less, the production of artificial zeolite may not be expected, and if it is allowed to react for 10 hours or more, the economy may be impaired. As for the reaction temperature, if the reaction is carried out at 80 ° C. or less, the reaction takes time and the economic efficiency is impaired. If the reaction is carried out at 180 ° C. or more, the crystal water of the artificial zeolite is evaporated and the properties of the artificial zeolite are changed. There is.

  The results of actually confirming the effects of the present invention will be shown below. However, the conditions and results shown below are examples of the present invention, and the present invention is not limited to the following description.

[Comparative Example 1]
First, 50 kg of coal ash as a raw material, 41.3 L of caustic soda 48% solution, and 60.1 L of water are mixed and stirred, heated to 140 ° C., and held for 1 hour to generate zeolite. Thereafter, slaked lime was added to 12.6 L of a 39% iron chloride solution so that the pH was 3 or more to produce iron hydroxide, and the previous zeolite was added and stirred therein, and then allowed to stand for 0.5 hour. Then, solid-liquid separation is performed with a dehydrator, and 250 L of water is added to the solid side for washing, followed by dehydration and drying again to produce an iron component-containing artificial zeolite.

[Example 1]
As an example of blending in the method of the present invention, 400 kg of coal ash, 150 L of caustic soda 48% solution, 100 L of iron chloride 39% solution, and 650 L of water were mixed and stirred, and hydrothermal treatment was performed at 96 ° C. for 6 hours. Thereafter, it was dehydrated and washed by adding 2000 L of water. Then, it was dehydrated again and dried to produce an iron component-containing artificial zeolite.

The characteristics of the artificial zeolite produced in Example 1 above are shown in Table 1 below in comparison with Comparative Example 1.

[Comparative Example 2]
First, 50 kg of coal ash as a raw material, 12.5 L of caustic soda 48% solution, and 84.5 L of water are mixed and stirred, heated to 140 ° C., and held for 1 hour to produce zeolite. Thereafter, slaked lime was added to 12.5 L of a 39% iron chloride solution so that the pH was 3 or more to produce iron hydroxide, and the previous zeolite was added and stirred therein, and then allowed to stand for 0.5 hour. The solid component is separated into solid and liquid by a dehydrator, washed with 250 L of water added to the solid side, dehydrated again and dried to produce an iron component-containing artificial zeolite.

[Example 2]
As an implementation example in the method of the present invention, 50 kg of coal ash, 16 L of caustic soda 48% solution, 12.5 L of iron chloride 39% solution, and 81 L of water were mixed and stirred, heated to 140 ° C. and held for 1 hour. Then, it dehydrated and washed by adding 250 L of water. Then, it was dehydrated again and dried to produce an iron component-containing artificial zeolite.

The characteristics of the artificial zeolite produced in Example 2 above are shown in Table 2 below in comparison with Comparative Example 2.

[Example 3]
As an example of blending in the method of the present invention, 400 kg of coal ash, 128 L of caustic soda 48% solution, 50 L of iron chloride 39% solution, and 720 L of water were mixed and stirred, and hydrothermal treatment was performed at 96 ° C. for 6 hours. Thereafter, it is dehydrated and washed with 2000 L of water. Further, it was again dehydrated and dried to produce an iron component-containing artificial zeolite. It carried out 8 times by the same method, and measured the amount of iron components of each product. The results are shown in Table 3.

  As described above, in the present embodiment, the manufacturing efficiency and the manufacturing cost can be greatly reduced by omitting the step of containing the iron component necessary in the conventional method. Moreover, an artificial zeolite having a high iron component content as compared with the conventional method could be produced. Furthermore, almost no iron hydroxide color such as reddish brown to ocher was observed, and an artificial zeolite with little coloring (light orange) could be produced. Therefore, it can be applied to a wide range of fields such as agriculture, horticulture, and concrete blocks.

Claims (5)

In a method for producing artificial zeolite by mixing waste products such as coal ash or industrial by-products of industrial products with an alkaline aqueous solution such as caustic soda and reacting them by heating,
A method for producing an iron-component-containing artificial zeolite, wherein an iron-containing material is added in at least one of the mixing step and the heating reaction to obtain an artificial zeolite containing an iron component.   2. The method for producing an iron component-containing artificial zeolite according to claim 1, wherein the iron component-containing substance is selected from iron chloride, iron hydroxide, iron oxide, iron sulfate, iron nitrate, or a mixture thereof. .   The method for producing an iron component-containing artificial zeolite according to claim 1 or 2, wherein the concentration of an aqueous alkali solution such as caustic soda during the heating reaction is adjusted to 0.8 to 5.0 mol / L.   The method for producing an iron component-containing artificial zeolite according to any one of claims 1 to 3, wherein an iron component concentration during the heating reaction is adjusted to 0.15 to 1.0 mol. An iron component-containing artificial zeolite produced by the production method according to any one of claims 1 to 4.