JPH0757684B2 - Method for producing high-purity silica from chaff - Google Patents
Method for producing high-purity silica from chaffInfo
- Publication number
- JPH0757684B2 JPH0757684B2 JP12875486A JP12875486A JPH0757684B2 JP H0757684 B2 JPH0757684 B2 JP H0757684B2 JP 12875486 A JP12875486 A JP 12875486A JP 12875486 A JP12875486 A JP 12875486A JP H0757684 B2 JPH0757684 B2 JP H0757684B2
- Authority
- JP
- Japan
- Prior art keywords
- silica
- acid
- ammonium
- purity
- chaff
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Lifetime
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Description
発明の目的 Purpose of the invention
本発明は、農産廃棄物であるモミガラから、高純度シリ
カを製造する方法に関する。The present invention relates to a method for producing high-purity silica from rice husk which is agricultural waste.
シリカは、天然物であるケイ石やケイ砂の主成分として
多量に産出するが、それらはかなりの不純物を含むの
で、ファインセラミックスの原料としては不満足なもの
である。半導体や太陽電池の製造に必要な高純度シリコ
ンを製造する技術が確立されているが、それに使用する
高純度のシリカは、きわめて高価である。 従って、かなりの純度、たとえば99.9％程度の純度のシ
リカを、低価格で供給することが要求されている。 一方、モミガラは多量に出る農産廃棄物であるが、その
利用の途は乏しい。発明者らは、モミガラを飼料として
実用できるようにすることを意図して研究し、水蒸気蒸
煮に先立ってフッ化水素酸で処理するとよいことを見出
し、すでに提案した（特願昭60−68217号）。これは、
モミガラ中のセルロース成分をおおっているシリカを溶
解除去してセルロース含有率を高めるとともに、水蒸気
蒸煮を効果的にするものである。 モミガラ中のケイ素成分の利用法としては、炭化ケイ素
の製造が行なわれているほか、モミガラを焼却してその
灰の中からシリカを回収することが検討されている。焼
却法は簡易で低コストではあるが、得られるシリカの純
度は高くない。もし精製を十分に行なえば、コストが高
くなって意味がなくなる。Silica is produced in large amounts as a main component of silica stones and silica sand which are natural products, but since they contain a considerable amount of impurities, they are unsatisfactory as raw materials for fine ceramics. Although a technique for producing high-purity silicon necessary for producing semiconductors and solar cells has been established, the high-purity silica used therein is extremely expensive. Therefore, it is required to supply silica having a considerable degree of purity, for example, about 99.9% at a low price. On the other hand, rice husk is a large amount of agricultural waste, but its use is scarce. The inventors studied with the intention of making the rice husk practical for use as a feed, found that it would be better to treat it with hydrofluoric acid prior to steam steaming, and have already proposed it (Japanese Patent Application No. 60-68217). ). this is,
Silica which covers the cellulose component in the rice husk is dissolved and removed to increase the content of cellulose and to make steam steaming effective. As a method of utilizing the silicon component in the chaff, the production of silicon carbide is being carried out, and incineration of chaff and recovery of silica from the ash are being considered. Although the incineration method is simple and low cost, the purity of silica obtained is not high. If refined enough, it would be costly and meaningless.
本発明の目的は、モミガラを原料として、高純度のシリ
カを低コストで製造する方法を提供することにある。 発明の構成An object of the present invention is to provide a method for producing high-purity silica at a low cost by using rice husk as a raw material. Structure of the invention
本発明のモミガラから高純度シリカを製造する方法は、
下記の諸工程からなっている。 （ａ） モミガラをフッ化水素酸溶液で処理して、その
中に含まれているケイ素化合物をヘキサフルオロケイ酸
として抽出する工程、 （ｂ） 抽出液にアンモニアを加えて、ヘキサフルオロ
ケイ酸を、ヘキサフルオロケイ酸アンモニウムをへて、
フッ化アンモニウムとシリカとに分解する工程、 （ｃ） 非晶質の粉末として析出したシリカを濾過分離
し、水洗および乾燥して高純度シリカを得る工程、およ
び （ｄ） フッ化アンモニウムを含む濾液に強酸を加えて
フッ化水素を生成させ、前記（ａ）工程に循環使用する
工程。 最初の工程（ａ）は、フッ化水素酸の濃度が１〜10％の
溶液を使用するとよい。処理したモミガラを続いて水蒸
気蒸煮して飼料にする方法と組み合わせて実施する場合
は、３〜５％が適当である。温度は、高い方が反応が速
やかに進むが、常温でも実用上支障ない。 次の工程（ｂ）は、好ましくは温度25〜50℃において、
抽出液中に適量のアンモニアガスを吹き込むか、または
濃厚なアンモニア水を添加して実施する。シリカの析出
は、非晶質体として沈でんするものではあるが、比較的
ゆるやかに反応を進める方が、不純物を包含することの
少い沈でんが得られて好ましい。従って、攪拌下に少量
ずつアンモニアを加える方式が適当である。 続く工程（ｃ）は、濾過分離に若干の技術を必要とす
る。工業的な濾過装置としては加圧型濾過機を使用し、
ひきつづき洗淨を行なうことが有利である。乾燥は、温
度130〜200℃とし、少なくとも４時間加熱して行なう。 最後の工程（ｄ）で使用する強酸は、硫酸が最適であ
る。 硫酸の添加によって、フッ化水素とともに硫酸水素アン
モニウムが生成するが、これはさらにアンモニアを加え
て硫酸アンモニアとすることができる。この操作は、合
成硫安の製造技術において知られているところに従い実
施すればよい。The method for producing high-purity silica from rice husk of the present invention,
It consists of the following steps. (A) a step of treating chafers with a hydrofluoric acid solution to extract the silicon compound contained therein as hexafluorosilicic acid; (b) adding ammonia to the extract to remove hexafluorosilicic acid. , Ammonium hexafluorosilicate,
A step of decomposing into ammonium fluoride and silica, (c) a step of separating silica precipitated as an amorphous powder by filtration, washing with water and drying to obtain high-purity silica, and (d) a filtrate containing ammonium fluoride A step in which a strong acid is added to produce hydrogen fluoride, and the hydrogen fluoride is circulated and used in the step (a). In the first step (a), it is preferable to use a solution having a hydrofluoric acid concentration of 1 to 10%. When it is carried out in combination with a method in which the treated rice husk is subsequently steam-steamed to form a feed, 3 to 5% is appropriate. The higher the temperature, the faster the reaction proceeds, but there is no problem in practical use at room temperature. The next step (b) is preferably at a temperature of 25 to 50 ° C.
Bubbling an appropriate amount of ammonia gas into the extract or adding concentrated ammonia water is carried out. The silica is precipitated as an amorphous substance, but it is preferable to proceed the reaction relatively slowly because precipitation containing less impurities can be obtained. Therefore, it is suitable to add ammonia little by little with stirring. Subsequent step (c) requires some technique for filtration separation. A pressure type filter is used as an industrial filtration device.
It is advantageous to carry out continuous washing. Drying is performed at a temperature of 130 to 200 ° C. and heating for at least 4 hours. The strong acid used in the final step (d) is most preferably sulfuric acid. The addition of sulfuric acid produces ammonium hydrogensulfate together with hydrogen fluoride, which can be further added with ammonia to form ammonium sulfate. This operation may be carried out according to what is known in the art of producing synthetic ammonium sulfate.
フッ化水素酸で処理することにより、モミガラ中のシリ
カは、まず四フッ化ケイ素になり、それが処理液中の水
により加水分解されて、直ちにコロイド状ケイ酸とヘキ
サフルオロケイ酸が生成する。 SiO2＋4HF→SiF4＋2H2O ……（ｉ） 3SiF4＋4H2O →2H2SiF6＋Si（OH）４ …（ii） コロイド状ケイ酸は、過剰にあるフッ化水素酸と反応し
て、ヘキサフルオロケイ酸になる。 Si（OH）４＋4HF→SiF4＋4H2O ……（iii） このようにして得たヘキサフルオロケイ酸にアンモニア
を加えると、まず中和が起り、 H2SiF6＋2NH3→（NH4）2SiF6 ……（iv） 生成したヘキサフルオロケイ酸アンモニウムは、さらに
アンモニアを加えると、分解する。 （NH4）2SiF6＋4NH3＋2H2O →6NH4F＋SiO2↓ ……（ｖ） 反応は、pHが中性〜弱アルカリ製の範囲で行なう。析出
したシリカを分離した液に硫酸を加えれば、フッ化水素
が遊離してくる。 NH4F＋H2SO4→NH4HSO4＋HF↑ ……（vi） さらにアンモニアを加えると、硫安に至る。 NH4HSO4＋NH3→（NH4）2SO4 ……（vii）By treatment with hydrofluoric acid, the silica in the chaff will first become silicon tetrafluoride, which will be hydrolyzed by the water in the treatment liquid to immediately produce colloidal silicic acid and hexafluorosilicic acid. . SiO 2 + 4HF → SiF 4 + 2H 2 O (i) 3SiF 4 + 4H 2 O → 2H 2 SiF 6 + Si (OH) 4 (ii) Colloidal silicic acid reacts with excess hydrofluoric acid. , Becomes hexafluorosilicic acid. Si (OH) 4 + 4HF → SiF 4 + 4H 2 O ...... (iii) When ammonia is added to the hexafluorosilicic acid obtained in this way, neutralization occurs first, and H 2 SiF 6 + 2NH 3 → (NH 4 ) 2 SiF 6 (iv) The generated ammonium hexafluorosilicate decomposes when ammonia is further added. (NH 4 ) 2 SiF 6 ＋ 4NH 3 ＋ 2H 2 O → 6NH 4 F ＋ SiO 2 ↓ (v) The reaction is carried out in the pH range of neutral to weakly alkaline. When sulfuric acid is added to the liquid from which the precipitated silica has been separated, hydrogen fluoride is liberated. NH 4 F + H 2 SO 4 → NH 4 HSO 4 + HF ↑ (vi) Addition of further ammonia leads to ammonium sulfate. NH 4 HSO 4 + NH 3 → (NH 4 ) 2 SO 4 …… (vii)
５％フッ化水素酸10にモミガラ1kgを浸漬し、常温で3
0分間放置した。モミガラを分離した液に、温度30℃の
条件で、25％アンモニア水1.5を約１時間かけて適下
し、その間、ゆっくりと撹拌した。 析出したシリカを分離して温水でよく洗い、温度150℃
のエアバス中に６時間放置して乾燥した。乾燥したシリ
カはボールミルで軽度に粉砕し、得られた製品を分析し
たところ、粒径15ミクロン以下の微粉末であって、Ｘ線
回折分析によればアモルファスシリカであった。化学分
析の結果、シリカの純度は99.9％以上であることを確認
した。 シリカの収量は155gで、これは原料モミガラの重量の1
5.5％に相当する。 次に、シリカを分離したフッ化アンモニウムを含む濾液
に98％H2SO4の350mlを時間をかけて加え、加熱蒸発さ
せ、希薄フッ化水素酸溶液を回収した。これを定量した
ところ、使用したフッ化水素酸の72％の回収率であっ
た。 発明の効果 本発明の方法に従えば、モミガラ中の重量で17〜22％を
占めるシリカが、99.9％以上という高純度で取得でき
る。かな製品は微粉末状であり、反応しやすい非晶質の
形態であることが高純度とあいまって、通常のファイン
セラミックス原料として申し分のないものである。 この方法の実施に使用する原料のうち、比較的高価なフ
ッ化水素酸は回収再利用でき、少量のロスを補えば足り
る。実施例におけるフッ化水素酸の回収率は低かった
が、これは主にモミガラを分離したときの、付着水の損
失によるものである。工業的実施に当っては、モミガラ
を圧搾脱水し、できるだけ液を回収することにより、フ
ッ化水素酸の回収率を高めることができる。そのほか、
消費する薬剤は硫酸のような安価なものに限られる。 使用する装置は耐フッ酸性を要求されるが、反応条件は
穏和であるから、常用のグレードで足りる。 従って、本発明の方法により製造されるシリカは、その
純度との対比において、十分に廉価ということができ
る。さきに開示したモミガラの飼料化技術と組み合わせ
て実施するとき、本発明方法は、いっそう有利になる。 モミガラは濃産廃棄物として年々多量に排出されるもの
であるから、本発明の完成によって、無尽蔵のシリカ資
源が確保できることになる。Immerse 1 kg of chaff in 10% 5% hydrofluoric acid,
It was left for 0 minutes. To the liquid from which the rice husks had been separated, 25% ammonia water 1.5 was appropriately applied for about 1 hour under the condition of the temperature of 30 ° C., while slowly stirring. Separate the precipitated silica and wash it well with warm water.
It was left to dry for 6 hours in the air bath. The dried silica was lightly crushed with a ball mill, and the obtained product was analyzed. As a result, it was a fine powder having a particle size of 15 μm or less, which was amorphous silica by X-ray diffraction analysis. As a result of chemical analysis, it was confirmed that the purity of silica was 99.9% or more. The yield of silica is 155g, which is 1% of the weight of the raw chaff.
Equivalent to 5.5%. Next, 350 ml of 98% H 2 SO 4 was added to the filtrate containing ammonium fluoride from which silica was separated over a period of time, and the mixture was heated and evaporated to recover a dilute hydrofluoric acid solution. When this was quantified, the recovery rate of the hydrofluoric acid used was 72%. EFFECTS OF THE INVENTION According to the method of the present invention, silica, which accounts for 17 to 22% by weight in chaff, can be obtained with a high purity of 99.9% or more. The kana product is a fine powder, and the amorphous form which is easily reacted with high purity makes it a perfect raw material for ordinary fine ceramics. Among the raw materials used for carrying out this method, relatively expensive hydrofluoric acid can be recovered and reused, and it is sufficient to compensate for a small amount of loss. Although the recovery rate of hydrofluoric acid in the examples was low, this was mainly due to the loss of attached water when chaff was separated. In industrial practice, the recovery rate of hydrofluoric acid can be increased by compressing and dehydrating rice husks and collecting the liquid as much as possible. others,
Consumed drugs are limited to inexpensive ones such as sulfuric acid. The equipment used is required to have hydrofluoric acid resistance, but since the reaction conditions are mild, a commonly used grade is sufficient. Therefore, the silica produced by the method of the present invention is sufficiently inexpensive in comparison with its purity. The method of the present invention becomes even more advantageous when it is carried out in combination with the feeding technology of rice husk disclosed above. Since a large amount of rice husk is discharged as a concentrated waste year after year, an inexhaustible silica resource can be secured by the completion of the present invention.
Claims (2)
度シリカを製造する方法： （ａ） モミガラをフッ化水素酸HF溶液で処理して、そ
の中に含まれているケイ素化合物をヘキサフルオロケイ
酸H2SiF6として抽出する工程、 （ｂ） 抽出液にアンモニアを加えて、ヘキサフルオロ
ケイ酸を、ヘキサフルオロケイ酸アンモニウム（NH4）2
SiF6をへて、フッ化アンモニウムNH4FとシリカSiO2とに
分解する工程、 （ｃ） 非晶質の粉末として析出したシリカを濾過分離
し、水洗および乾燥して高純度シリカを得る工程、およ
び （ｄ） フッ化アンモニウムを含む濾液に強酸を加えて
フッ化水素を生成させ、前記（ａ）工程に循環使用する
工程。1. A method for producing high-purity silica from chaffs comprising the following steps: (a) Treating chaffs with a hydrofluoric acid HF solution to convert the silicon compounds contained therein into hexafluoro. Step of extracting as silicic acid H 2 SiF 6 , (b) Addition of ammonia to the extract to convert hexafluorosilicic acid to ammonium hexafluorosilicate (NH 4 ) 2
Step of decomposing SiF 6 into ammonium fluoride NH 4 F and silica SiO 2 , (c) Step of separating silica precipitated as an amorphous powder by filtration, washing with water and drying to obtain high-purity silica And (d) a step in which a strong acid is added to a filtrate containing ammonium fluoride to generate hydrogen fluoride, and the hydrogen fluoride is circulated and used in the step (a).
使用し、フッ素水素を回収した後の硫酸水素アンモニウ
ムにアンモニアを加えて硫酸アンモニウムを得る工程を
含む特許請求の範囲第１項の方法。2. The method according to claim 1, further comprising the step of using sulfuric acid as a strong acid in the step (d) and adding ammonia to ammonium hydrogensulfate after recovering hydrogen fluoride to obtain ammonium sulfate.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP12875486A JPH0757684B2 (en) | 1986-06-03 | 1986-06-03 | Method for producing high-purity silica from chaff |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP12875486A JPH0757684B2 (en) | 1986-06-03 | 1986-06-03 | Method for producing high-purity silica from chaff |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS62288110A JPS62288110A (en) | 1987-12-15 |
| JPH0757684B2 true JPH0757684B2 (en) | 1995-06-21 |
Family
ID=14992637
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP12875486A Expired - Lifetime JPH0757684B2 (en) | 1986-06-03 | 1986-06-03 | Method for producing high-purity silica from chaff |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH0757684B2 (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| KR101048410B1 (en) * | 2010-08-13 | 2011-07-12 | 충남대학교산학협력단 | Preparation of superfine purified silica, and fibers simultaneously |
Families Citing this family (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5266289A (en) * | 1989-11-16 | 1993-11-30 | Nissan Chemical Industries Ltd. | Process for producing high-purity silica by reacting crude silica with ammonium fluoride |
| US5853685A (en) * | 1996-08-28 | 1998-12-29 | Erickson; William R. | Process for the production of high purity silica from waste by-product silica and hydrogen fluoride |
| KR100367839B1 (en) * | 2000-07-13 | 2003-01-10 | 주식회사 이코바이오 | the extracting method of silica from a herbaceous plant |
| WO2002066372A1 (en) * | 2001-02-19 | 2002-08-29 | Fundação De Amparo Á Pesquisa Do Estado De São Paulo | Oxides extracted from vegetal matter and process therefor |
| CN102616793B (en) * | 2012-03-26 | 2014-02-26 | 阳光凯迪新能源集团有限公司 | Method for eliminating metal ions in rice hulls by utilizing industrial flue gas |
| CN103950941A (en) * | 2014-05-12 | 2014-07-30 | 连云港市东海县宏伟石英制品有限公司 | Method for chemically preparing ultra-high-purity quartz powder |
| RU2691347C1 (en) * | 2018-05-08 | 2019-06-11 | Общество с ограниченной ответственностью "Новые химические продукты" | Method of processing hexafluorosilicic acid to obtain hydrogen fluoride |
-
1986
- 1986-06-03 JP JP12875486A patent/JPH0757684B2/en not_active Expired - Lifetime
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| KR101048410B1 (en) * | 2010-08-13 | 2011-07-12 | 충남대학교산학협력단 | Preparation of superfine purified silica, and fibers simultaneously |
Also Published As
| Publication number | Publication date |
|---|---|
| JPS62288110A (en) | 1987-12-15 |
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