WO2001085614A1

WO2001085614A1 - Method for production of silica gel

Info

Publication number: WO2001085614A1
Application number: PCT/JP2001/003222
Authority: WO
Inventors: Yi Ze Jin
Original assignee: Kabushiki Kaisha B . M
Priority date: 2000-05-08
Filing date: 2001-04-16
Publication date: 2001-11-15
Also published as: AU4691701A; JP2003171114A

Abstract

A method for production of a silica gel which comprises burning the husk of a grain to provide a burned ash, charging the burned ash in an strongly alkaline aqueous solution containing an alkali metal compound, followed by agitating, to prepare a liquid mixture, heating the mixture and then separating the mixture into an ash and a filtrate, steaming the ash with hydrochloric acid to produce an activated carbon as a by-product, cooling rapidly the filtrate to precipitate a solid, admixing the solid with an acid and heating the resultant mixture, separating the mixture into a solid product and a liquid, washing the solid product with water followed by drying to produce a high purity silica gel. The method allows the production of a high purity silica gel from the husk of a grain which is produced in a large quantity and is treated as a waste, with a simple process mainly comprising heating with an aqueous solution and cooling and with ease.

Description

Light

Manufacturing method for iris gel

TECHNICAL FIELD The present invention relates to a method for producing a shiri gel, which produces a silk gel from cereal husks. Itoda

Skill

Conventionally, high-purity silica has been used as an inorganic material such as semiconductors, optical fins, solar cells, and various types of fincer mixes. It is widely used.

And high-purity silica is purified by melting natural ore at a high temperature. However, high-grade natural ore is gradually decreasing, and high-purity silica is available because of the high manufacturing costs of melting at high temperatures. Is becoming more difficult to handle.

On the other hand, rice, wheat, beans, and other foods are widely used as staple foods, but they produce a large amount of shells and only a part of organic fertilizer. It is only used for such purposes. For this reason, most of these grain husks are incinerated as industrial waste, which costs extra.

As mentioned above, it is difficult to obtain high-cost silica if high-grade silica is purified from natural ore. It is the current situation. Also, the grain shell Most of them are not used and are treated as industrial waste at a separate cost.

The present invention has been made in view of such a point, and a high-purity silica gel that can easily be manufactured by using wastes can be easily produced. The purpose is to provide a method of manufacturing the tools. Disclosure of the invention

The method for producing silica gel according to the present invention is as follows: the shell of a grain is calcined to form calcined ash, and the calcined ash is added to a water solution containing a strong alkaline component. Is stirred and mixed to prepare a mixed solution, and the mixed solution is heated to a temperature and then solid and liquid separated into a filtrate and an ash.The filtrate collected by the solid / liquid separation is cooled. After that, the solid and liquid components are separated into a liquid component and a solid component, and the solid component collected by the solid / liquid separation is washed. Then, the calcined ash obtained by calcining the hull of the substance is stirred and mixed in a water solution containing a strong alkaline component, heated, and then the filtrate obtained by solid-liquid separation is cooled. If the collected solids are washed and washed, the husks of cereal grains, which are particularly large quantities that become waste, are used as raw materials, heated to an aqueous solution, and cooled by heating. With a simple process, high-purity silica gel can be easily produced.

In addition, the method for producing the silica gel of the present invention is as follows. In the washing of the solid component, the solid component is mixed with an acid, heated, and then solidified into a solution and a solid product. The liquid is separated, and the solid matter is washed with water. The solids separated from the solids and liquids are mixed with an acid. After heating and heating, the solid matter separated from solid and liquid is washed with water to wash the solid matter, and together with silica gel purified from calcined ash. The impurities in the husk mixed into the shell are removed with an acid to ensure the production of high-purity silica gel.

Furthermore, the method for producing silica gel according to the present invention is to convert the solution collected by solid-liquid separation into an acid that can be mixed with solids. The solids are removed by solid-liquid separation, and the solids are removed.The acid that mixes the solid solution with a solution that hardly changes from the composition of the acid that cleans the solids. As a result, the acid can be reused and the production cost can be reduced.

In addition, the method of producing the silica gel of the present invention is such that the strong alkaline component contains a small amount of a sodium compound and a potassium compound. It is all either. Then, the strong alkaline component in the aqueous solution mixed with the calcined ash is converted into a sodium sulfide compound and a reactive component having high reactivity with the silica component in the calcined ash. Since at least some of the rubber compound is used, silica gel can be efficiently purified and separated from calcined ash, and silica gel purification efficiency can be improved. Wear .

Furthermore, the method for producing silica gel according to the present invention is characterized in that, after cooling the filtrate, solid-liquid separation is performed, and the collected liquid is mixed with calcined ash. It is an aqueous solution containing the components. A solution containing the same strong alkaline component as the strong alkaline component in the aqueous solution into which the solid-liquid separation is performed after the mixture is cooled and the calcined ash is mixed. Aqueous solution containing strong alkaline components that mixes the liquid component with calcined ash As a result, the water solution can be reused and the production cost can be reduced. '

In addition, the method for producing silica gel of the present invention involves steaming ash with an acid. Since the ash is steamed with acid, ash from which organic components have been removed from the burnt ash that has been burned by burning organic matter from the shell of 榖 is removed. It has a myriad of fine pores, and can be produced using activated carbon as a by-product in the process of producing silica gel, making the use of waste grain shells without waste. it can .

Furthermore, in the method for producing silica gel according to the present invention, the husks of the grains are rice husks. In addition, since rice husks having a relatively high silica content are used as animal husks, silica gel can be produced at low cost. Brief description of the drawings

FIG. 1 is a flowchart showing a manufacturing process of an embodiment of a method for manufacturing a silica gel according to the present invention. Best mode for carrying out the invention

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

First, as a raw material, cereals such as rice, barley, barley-barley, wheat, millet, millet, millet, etc. Red beans, mung beans, green beans, peanuts, cereals in the legumes, such as endome, sono in the family of deciduous family, The quinoa and the cucumber sennin varieties consume a large amount of shells, especially rice, barley, barley, soybeans, red beans, peanuts, etc. It is preferable to use those that are generated, especially rice husks that are rich in silica.

Then, the husks of the grains such as the rice hulls are fired using, for example, a rotary furnace to produce burnt ash.

Thereafter, the calcined ash is poured into an aqueous solution containing a strong calorie component prepared in advance, and the mixture is stirred and mixed to prepare a mixed solution. This aqueous solution contains an alkali metal compound which is a strong alkali metal component in water, for example, sodium carbonate such as sodium carbonate and sodium hydroxide. And a mixture of at least one of a hydrogen compound, such as a hydroxyl compound, and a hydroxyl group.

It should be noted that sodium carbonate is more than 0.1 Wt.% In water and less than 31 Wt.%, Sodium hydroxide is more than 0.1 Wt.% In water and more than 0.1 Wt.%. % Or less, potassium carbonate in water ◦ .1 Wt.% Or more and 61 Wt.% Or less, hydroxylated potassium in water 0.1% or more % To prepare an aqueous solution with the addition of less than 6 Wt.%, The amount of the alkaline metal compound, which is a strong alkaline component added to the mixture, is minimized. If the value is lower than the lower limit, inorganic components such as ash in the calcined ash cannot be sufficiently eluted, and the inorganic components cannot be recovered efficiently. If the amount of addition exceeds the maximum value, the alkali metal compound does not completely dissolve, and the excess increases the cost. It becomes. For this reason, the addition amount should be set within the above-mentioned range.

Then, the temperature of the mixture obtained by stirring and mixing the calcined ash with the aqueous solution is adjusted to, for example, 0 ° C or more and 150 ° C or less, preferably 80 ° C or less. Heat to 100 ° C or less.

Here, when the temperature is lower than 0 ° C, the reaction rate between the alkali metal ion in the mixed solution and the inorganic component in the calcined ash is reduced, and the inorganic component is efficiently removed. If it cannot be separated from calcined ash, or if the temperature is higher than 150 ° C, the reaction rate will not be too high, requiring a large amount of heat, and the viscosity of the mixture will be high. The degree of stirring is so high that stirring becomes difficult, and an efficient reaction cannot be performed. Therefore, heat at a temperature of 0 ° C or more and 150 ° C or less, preferably 80 ° C or more and 100 ° C or less.

When the mixture is heated, the steam is collected and returned so that the water does not evaporate. Also, for example, using a Baume specific gravity meter, it is possible to appropriately add hot water by increasing the liquid specific gravity.

Thereafter, the heated mixture is subjected to solid-liquid separation into a filtrate and ash by, for example, vacuum filtration. The collected ash is subjected to a steaming heat treatment in which the ash is steamed with an acid such as hydrochloric acid, for example, to be activated carbon as a by-product.

Then, rapidly cool the collected filtrate. This quenching is, for example, rapid cooling to a temperature of 0 ° C or more and 100 ° C or less, that is, a temperature far lower than the heating temperature. Due to this quenching, the filtrate is suspended in a white color, and a solid content precipitates out. Next, the filtrate from which the white solid has been deposited is solid-liquid separated into a white solid and a liquid, and the solid is washed with distilled water or the like.

Then, the solid content washed with water is washed, that is, the solid content is mixed with an acid such as concentrated nitric acid or concentrated sulfuric acid by stirring, for example, heated at 100 ° C., and then solidified. Solid-liquid separation with the washing solution. Here, concentrated acid may be used as the acid, but, for example, strontium oxide, aluminum oxide, etc. derived from the shell are dissolved in the acid. For this reason, concentrated nitric acid and concentrated sulfuric acid are preferred.

Further, the collected solid is washed with distilled water or the like, and the solid is dried to obtain a high-purity silica gel, which is amorphous silicic acid.

Next, the operation of the above embodiment will be described.

Animal husks generally contain silica. In particular, dried rice hulls contain about 13 Wt.% To 29 Wt.% Of inorganic components, and about 87 Wt.% To 97% of this inorganic component is silica. It is known that it is power (Hokkaido Industrial Development Laboratory, 1984). It is also known that as a chemical component of the calcined ash obtained by firing rice husks, silica is contained at 92.94%, and it is also known that it can be used (Fukuoka Prefecture).

Then, calcined ash obtained by calcining husks of grains such as rice hulls is prepared by stirring and mixing with a strong alkaline component, and the adjusted mixture is heated. Inorganic components such as silica and trace inorganic components in calcined ash Reacts with component metal compounds.

That is, for example, when sodium carbonate is used as a strong alkaline component,

_{_{_{Si0 2 + 2NaC0 3 + H 2}}} 0 → Na 2 Si0 3 + 2NaHC0 3

As shown in the reaction formula, silica in the calcined ash reacts with sodium carbonate and elutes as sodium mesosilicate into the aqueous solution. At the same time, some of the trace amounts of other inorganic components that become impurities in the calcined ash are also eluted into the aqueous solution. The elution of impurities is thought to be eluted as a sodium compound in the same way as sodium silicate.

As described above, the filtrate collected by solid-liquid separation such as vacuum filtration has a state in which other small inorganic components in the calcined ash are dissolved together with silica. The carbon that has not been burned remains as ash.

The fine ash content is due to the fact that inorganic components such as silica and impurities are dissolved out together with pores when water and carbon are burned off by firing. It is in a state where there are countless pores. For this reason, steam treatment with an acid such as hydrochloric acid to form fine pores and cleaning of impurities enables high quality activated carbon to be obtained. Is produced as a by-product.

By rapidly cooling the filtrate in which silica and a small amount of inorganic components are dissolved, the silica gel becomes saturated and precipitates and precipitates. That is, for example,

_{_{_{Na 2 Si0 3 + 2NaHG0 3 →}}} Si0 2 -nH 2 0 + 2Na 2 C0 3 + H 2 0 Reaction proceeds, and sodium silicate dissolved as sodium silicate is decomposed into silica gel and sodium is released. Ion reacts with sodium hydrogen carbonate that dissolves in the filtrate, and is again dissolved in the filtrate as sodium carbonate.

In addition, some trace amounts of inorganic compounds or inorganic compounds that can be directly dissolved also precipitate as oxides and hydrates. Conceivable .

In addition, the inorganic component that has a strong bond with sodium ion is almost dissolved as a sodium compound. In addition, ions of inorganic components that do not reach saturation even after quenching remain dissolved.

As described above, the solid component extracted by quenching has silica gel as a main component and attaches to trace amounts of inorganic oxides, hydrates, and silica gel. The liquid component containing inorganic components to be attached or replaced, etc., separated from the solid component has a composition almost the same as that of the aqueous solution mixed with the calcined ash. In other words, it becomes a water solution in which sodium carbonate of the strong calcium component is dissolved, and can be used as it is, or can be used after it has been stored once. Can be reused after purification, such as removing impurities, and then used after purification.

In addition, by heating the solid component mixed with an acid such as concentrated nitric acid, the silica gel hardly dissolves and the solid state remains in a solid state. And other trace inorganic components dissolve as nitric oxide. Therefore, mix with acid After solid-liquid separation and further washing with water, high purity from which impurities have been removed, for example, silica gel of 99.9% or more can be obtained. .

In addition, since the inorganic components eluted by the acid are very small, the acid used for cleaning is hardly contaminated, so it can be used as it is. Can be reused after it has been stored, and can be reused after it has been purified and processed to remove impurities. '

As described above, in the above embodiment, the fired ash obtained by firing the husk of the grain is stirred and mixed in an aqueous solution containing a strong aluminum component, heated, and solid-liquid separated. Because the collected filtrate is cooled to separate and wash the solids, the husk of the cereal grains containing silica in a relatively large amount, which is a particularly large amount of waste and is an inorganic component, becomes waste. Is a simple process that uses a highly alkaline water solution to heat, cools and collects solids, and uses a high-purity series that contains few impurities. High-purity silica, which can be used to easily purify power gels and separately dehydrated, for example, for electrical components, dissolves ore. Easily and inexpensively manufactured without the need for high energy it can .

In addition, the washing of the collected solids involves mixing with an acid, particularly concentrated nitric acid or concentrated sulfuric acid, heating, and then washing with water. A small amount of inorganic components can be separated and removed, and a high-purity silica gel can be easily produced. The acid used for the washing contains a small amount of a compound derived from the husk of the grain, and can be reused for the washing, thereby reducing the production cost. .

Furthermore, as a strongly alkaline water solution used to elute the silica component from the calcined calcined ash, the calcining component in the calcined ash is used. The use of at least one phenolic metal compound, which is highly reactive with sodium and carbohydrate compounds, requires It is possible to highly purify and separate iris gel from adult ash, thereby improving the purification efficiency of silica gel.

In addition, since the aqueous solution can be rapidly cooled and the silica gel collected after the silica gel can be reused as an aqueous solution, the manufacturing cost can be further reduced. .

The remaining ash from which the silica component was eluted from the calcined ash has a porous structure similar to that of activated carbon, and has a myriad of pores. And high-quality activated carbon as a by-product by washing with acid to form fine pores and to remove residual inorganic components and the like. In addition to making effective use of the waste husks, there is little to be treated as waste, and waste treatment Costs can also be saved.

In addition, since rice husks are used as cereal husks, which have a relatively large amount of silica and generate a large amount of silica, silica gel can be produced efficiently. .

In the above embodiment, the cereal shell Not only rice hulls but also wheat cereals such as barley, rye, oats, millet, millet, millet, etc., and soybeans, red beans and mung beans. Beans, peanuts, endowed beans and other legumes, such as cereals, sonoaceae in the family Desertidae, quinoa in the family Akaza, sennin cocos in the family Hyu, etc. Similarly, high-purity silica gel can be easily produced using any of the cereal shells.

The hulls of the cereal shells may be fired by any method. A more efficient and uniform combustion method, for example, a rotary furnace is preferred.

In addition, although the mixture was heated, even if the mixture was heated rapidly and rapidly cooled to a lower temperature than the mixture, the gel could be precipitated. Okay.

In addition, it is not necessary to heat it only by mixing it with an acid during washing. It is also preferable that the heat of the squid can increase the rate of elution of the impurities and can be efficiently cleaned.

The solids separated from the quenched filtrate were washed with water, then stirred and mixed with an acid, heated and heated, but washed with water. It is permissible to wash with acid directly without washing. In addition, by pre-washing with water, adhering alkaline metal compounds are removed, and the acid at the time of cleaning is removed from the alkaline metal compounds. It is not consumed, and the manufacturing cost can be reduced.

On the other hand, the ash may be treated separately without producing an activated carbon by-product by steaming with an acid to produce activated carbon.

Next, a practical example of using rice husks to produce silica gel Explain.

Rotate the rotary furnace using 1 ton of rice hulls in a cylindrical furnace with a diameter of 1 m and a length of 2 m using a mesh of 80 mesh. It burned from the outer peripheral surface to obtain 2886 kg of burnt ash.

Then, 280 kg of the calcined ash obtained by pulverizing the calcined ash into an 80 to 100 mesh was converted into 4666.66 liters of water. Stir and mix with 493.98 kg of sodium acid to prepare a mixture.

After this, heat the mixture at 80 ° C. In addition, hot water was supplied while controlling the specific gravity appropriately using a volume hydrometer.

Then, the heated mixture was immediately filtered through a vacuum, and the collected filtrate was rapidly cooled in ice water to make it supersaturated.

Next, the cooled filtrate was filtered, and the collected solid fraction was stirred and mixed with the same volume of concentrated nitric acid (about 10 liters), and heated at 100 ° C for 1 hour. Later, it was left still for one hour.

Then, the supernatant was removed, and the remaining solid matter was washed with distilled water, dried, and dried to obtain a 99.9% pure gel. 9 kg was obtained.

Further, the mixed solution was subjected to vacuum filtration, and the collected ash was subjected to a steam treatment with hydrochloric acid, washed with water and dried to obtain 174 kg of activated carbon. Possibility of industrial use As described above, the method for producing the silica gel of the present invention is, for example, a semiconductor, an optical fiber, a solar cell, and various types of fine ceramics. It is used as a method for producing inorganic materials.

Claims

Request box

1. Bake the husks of the grain to make baked ash,

The above-mentioned calcined ash was stirred and mixed into an aqueous solution containing a strong aluminum component to prepare a mixed solution.

Word a;

After heating this mixture, the mixture was separated into filtrate and ash by solid-liquid separation.

The filtrate collected by the solid-liquid separation is cooled, then solid-liquid separated into a liquid component and a solid component, and the collected solid component is washed by the solid-liquid separation. Method for producing silica gel.

2. To wash solids, mix the solids with an acid, heat it, then separate it into a solution and solids, and wash the solids with water.

The method for producing a silica gel according to claim 1, which is characterized by the above feature.

3. The solution collected by solid-liquid separation is converted into an acid that can be mixed with solid components.

The method for producing a silica gel as described in Paragraph 2 of the scope of the claim which features this.

4. Strong alkaline components are at least one of sodium compounds and rheodium compounds

A method for producing a silica gel according to any one of claims 1 to 3, which is characterized by the scope of the claim that features this.

5) The filtrate collected after cooling the filtrate and separating it into solid and liquid fractions. Is an aqueous solution containing a strong alkaline component in which the calcined ash is mixed.

A method for producing a silica gel as set forth in any one of paragraphs 1 to 4 of the scope of the claim characterized by this.

6. Steam the ash with acid

The method for producing a silica gel according to any one of paragraphs 1 to 5 of the scope of the claim which features this.

7. The grain husk is rice husk

The method for producing a silica gel according to any one of paragraphs 1 to 6 of the scope of the claim featuring this feature.