JPS5934131B2 - Method for producing silicofluoride soda from fluorine-containing exhaust gas - Google Patents
Method for producing silicofluoride soda from fluorine-containing exhaust gasInfo
- Publication number
- JPS5934131B2 JPS5934131B2 JP3249981A JP3249981A JPS5934131B2 JP S5934131 B2 JPS5934131 B2 JP S5934131B2 JP 3249981 A JP3249981 A JP 3249981A JP 3249981 A JP3249981 A JP 3249981A JP S5934131 B2 JPS5934131 B2 JP S5934131B2
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- Japan
- Prior art keywords
- fluorine
- exhaust gas
- silicofluoride
- sodium
- containing exhaust
- 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.)
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Description
【発明の詳細な説明】
本発明は弗素含有排ガスを有効に利用して高純度、粗粒
の珪弗化ソーダを安価に製造する方法に関するものであ
る。DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for manufacturing highly pure, coarse-grained sodium silicofluoride at low cost by effectively utilizing fluorine-containing exhaust gas.
更に詳しくは、湿式燐酸、乾式燐酸、過燐酸石灰、焼成
燐肥、溶成燐肥、氷晶石製造、アルミニウム精練工業な
どにおいて発生する弗素含有排ガスから、珪弗化ソーダ
を極めて安価に製造する吉共に、排ガス中の弗素分を有
効利用し廃棄物として処理する量を極めて低減する方法
を提供するものである。More specifically, we will produce sodium silicofluoride at an extremely low cost from fluorine-containing exhaust gas generated in wet phosphoric acid, dry phosphoric acid, lime superphosphate, calcined phosphorous fertilizer, melted phosphorous fertilizer, cryolite production, aluminum smelting industry, etc. In addition, the present invention provides a method for effectively utilizing the fluorine content in exhaust gas and extremely reducing the amount disposed of as waste.
従来珪弗化ソーダの工業的な製造方法としては、湿式燐
酸液を精製する過程において、含有する弗素分を苛性ソ
ーダや炭酸ソーダなどのナトリウム化合物と反応させて
珪弗化ソーダを得る方法が一般に用いられている。Conventional industrial methods for producing sodium silifluoride include a method in which the fluorine content is reacted with a sodium compound such as caustic soda or soda carbonate in the process of refining a wet phosphoric acid solution to obtain sodium silifluoride. It is being
この方法は、湿式燐酸中の不純物たる弗素分を有効利用
すると云う点で経済的ではあるもの\、一方の原料であ
るナトリウム化を、湿式燐酸液に対し余分なアニオンを
もたらさない苛性ソーダや炭酸ソーダなどの特定の化合
物に限定せざるを得ないので更に安価なナトリウム源が
望まれている。This method is economical in that it makes effective use of the fluorine content, which is an impurity in wet phosphoric acid.However, one raw material, sodium chloride, is replaced with caustic soda or carbonate soda, which does not bring any extra anions to the wet phosphoric acid solution. Therefore, a cheaper source of sodium is desired.
一方、弗素含有排ガスの処理方法という観点からるると
、弗素分を不要物として含有する前記各燐酸工業やアル
ミニウム製練工業などから発生する排ガスは大気放出に
際し弗素分を規制値以下に除去することが義務づけられ
ており、従来は石灰乳、苛性ソーダ水溶液などで処理し
て、弗素分を弗化カルシウム、珪弗化カルシウム、珪弗
化ソーダ等の化合物として分離していたが、これ等の弗
素化合物は種々の化合物が同伴し、品位が悪く、多くの
場合利用価値もな〈産業廃棄物として処理されていた。On the other hand, from the perspective of a method for treating fluorine-containing exhaust gas, it is necessary to remove the fluorine content of the exhaust gases generated from the above-mentioned phosphoric acid industries, aluminum smelting industries, etc., which contain fluorine content as an unnecessary substance, to below the regulation value when releasing it into the atmosphere. Conventionally, the fluorine content was separated into compounds such as calcium fluoride, calcium silicofluoride, and sodium silicofluoride by treating with milk of lime or an aqueous solution of caustic soda, but these fluorine compounds It is accompanied by various compounds, is of poor quality, and in many cases has no useful value (was treated as industrial waste).
本発明者等は上記状況に鑑み鋭意検討した結果、弗素含
有排ガスを水に吸収させて珪弗化水素酸水溶液とし、こ
れと海水とを反応させることにより高純度で、取扱の容
易な粗粒の珪弗化ソーダを極めて安価に製造することが
でき、弗素含有排ガスの処理の負担を軽減し、しかも弗
素分の有効利用が可能であることを見出し、本発明を完
成するに至ったものである。As a result of intensive studies in view of the above circumstances, the inventors of the present invention have found that by absorbing fluorine-containing exhaust gas into water to form a hydrosilicic acid aqueous solution and reacting this with seawater, it is possible to create coarse particles with high purity and ease of handling. They discovered that it is possible to produce sodium silicofluoride at an extremely low cost, reduce the burden of processing fluorine-containing exhaust gas, and make effective use of the fluorine content, leading to the completion of the present invention. be.
すなわち、本発明の方法は、弗素含有排ガスを水に吸収
させて珪弗化水素酸水溶液とした後、該珪弗化水素酸と
塩化ナトリウムとを反応させて珪弗化ソーダを製造する
方法において、珪弗化水素酸水溶液の濃度を10〜30
重量%とし、塩化ナトリウム源として海水を、該海水中
の塩化ナトリウムが、珪弗化水素酸1モルに対し1.5
〜2.5モルとなるような量で使用することを特徴とす
る弗素含有排ガスからの珪弗化ソーダの製造方法である
。That is, the method of the present invention is a method for producing sodium silicofluoride by absorbing fluorine-containing exhaust gas into water to form an aqueous solution of hydrosilicofluoric acid, and then reacting the hydrofluoric acid with sodium chloride. , the concentration of the hydrosilicofluoric acid aqueous solution is 10 to 30.
When using seawater as a sodium chloride source, the sodium chloride in the seawater is 1.5% by weight per mol of hydrosilicofluoric acid.
This is a method for producing sodium silicofluoride from fluorine-containing exhaust gas, characterized in that the amount is used in an amount of 2.5 mol to 2.5 mol.
この方法における反応を、反応式で示すと、弗素含有排
ガス中の弗素分を(1)式によって珪弗化水素酸水溶液
にした後、該珪弗化水素酸水溶液と海水中の塩化ナトリ
ウムとを(2)式によって反応させることで高純度、粗
粒の珪弗化ソーダとするものである。The reaction in this method is shown by a reaction formula. After converting the fluorine content in the fluorine-containing exhaust gas into an aqueous solution of hydrosilicofluoric acid using equation (1), the aqueous solution of hydrosilicic acid and sodium chloride in seawater are combined. By reacting according to the formula (2), highly pure, coarse-grained sodium silicofluoride is produced.
2HF + 5IF4 →H2SiF6 ・・・・
・・ (1)H2SiF6+2NaCl−+Na2Si
F6+2HCl・・・(2)通常弗素含有排ガス中に含
まれる弗素分は、弗化水素及び四弗化珪素の形で存在す
るので、そのまメ使用できるが、排ガス中の弗化水素成
分が過剰の場合には、弗化水素酸水溶液を得る工程で、
例えば珪藻土等の活性シリカ成分を加えて(3)式に示
す反応によりモル比をバランスさせて使用すればよい。2HF + 5IF4 →H2SiF6 ・・・・
... (1) H2SiF6+2NaCl-+Na2Si
F6+2HCl... (2) Fluorine contained in fluorine-containing exhaust gas usually exists in the form of hydrogen fluoride and silicon tetrafluoride, so it can be used as is, but if the hydrogen fluoride component in the exhaust gas is excessive. In the case of , in the process of obtaining an aqueous hydrofluoric acid solution,
For example, an active silica component such as diatomaceous earth may be added to balance the molar ratio by the reaction shown in equation (3).
4HF+S i02→S t F4+ H2O・・・・
・・・・・・・・ (3)また弗化水素と四弗化珪素の
モル比(HF:S iF4 )は、厳密に2:1に調節
する必要はなく、1.8〜2.2:1程度であればよく
、得られる珪弗化ソーダの品質及び排ガスの処理に問題
はない。4HF+S i02→S t F4+ H2O...
(3) Furthermore, the molar ratio of hydrogen fluoride and silicon tetrafluoride (HF:SiF4) does not need to be strictly adjusted to 2:1, but is between 1.8 and 2.2. : It is sufficient if it is about 1, and there is no problem in the quality of the obtained sodium silicofluoride and in the treatment of exhaust gas.
なお、排ガスを水に吸収させて得た珪弗化水素酸水溶液
は、表−1にその成分の1例を示す如く燐酸分、鉄分な
どの不純物を含んでいる液であっても、水溶性の不純物
であれば、珪弗化ソーダを固液分離したあとのP液中に
溶解して除去されるので、得られる珪弗化ソーダの品質
には殆ど影響しない。Note that the aqueous solution of hydrosilicofluoric acid obtained by absorbing exhaust gas in water is water-soluble even if it contains impurities such as phosphoric acid and iron, as shown in Table 1. If these impurities are dissolved in the P solution after solid-liquid separation of the sodium silicofluoride and removed, the quality of the obtained sodium silicofluoride is hardly affected.
本発明の方法においては、珪弗化水素酸水溶液と海水を
接触させて反応させるのであるが、両液の接触と同時に
珪弗化ソーダの結晶が析出してくるので、その接触条件
、特に海水と接触させる珪弗化水素酸水溶液の濃度及び
塩化ナトリウムのモル比が、得られる珪弗化ソーダの品
質及び収率並びに濾過、乾燥等の操作性に大きく影響を
与える。In the method of the present invention, an aqueous solution of hydrosilicofluoric acid and seawater are brought into contact and reacted, but crystals of sodium silicofluoride precipitate at the same time as the two solutions come into contact. The concentration of the hydrosilicofluoric acid aqueous solution and the molar ratio of sodium chloride that are brought into contact with the sodium silicofluoride have a large influence on the quality and yield of the obtained sodium silicofluoride, as well as on the operability of filtration, drying, etc.
すなわち、本発明の方法では、珪弗化水素酸水溶液の濃
度を10〜30重量%の範囲に調整するのが好ましく、
さらに20〜25重i%の範囲が最適である。That is, in the method of the present invention, it is preferable to adjust the concentration of the hydrosilicofluoric acid aqueous solution to a range of 10 to 30% by weight,
Furthermore, a range of 20 to 25 weight i% is optimal.
珪弗化水素酸水溶液の濃度が30重量%を越えると得ら
れる珪弗化ソーダの粒子径が非常に小さくなり固液分離
が非常に困難となるのみならず、結晶への母液の付着量
増加による乾燥能力低下、乾燥に要するエネルギーの増
加、製品中の不純物の増加などの悪影響を招く。When the concentration of the hydrosilicofluoric acid aqueous solution exceeds 30% by weight, the particle size of the resulting sodium silicofluoride becomes extremely small, making solid-liquid separation extremely difficult, and the amount of mother liquor adhering to the crystals increases. This leads to negative effects such as a decrease in drying capacity due to drying, an increase in the energy required for drying, and an increase in impurities in the product.
また珪弗化水素酸水溶液の濃度が10重量%未満では、
30重量%を越える場合と同様生成する珪弗化ソーダの
粒子径が小さくなるのに加えて、はっきりした原因は不
明ではあるが、珪弗化ソーダの収率が低下し、弗素分の
回収率が落ちるので好ましくない。Furthermore, if the concentration of the hydrosilicofluoric acid aqueous solution is less than 10% by weight,
In addition to the particle size of the produced sodium silifluoride becoming smaller than when the amount exceeds 30% by weight, the yield of sodium silifluoride decreases, although the exact cause is unknown, and the recovery rate of fluorine content decreases. It is not desirable because it will fall off.
次に珪弗化水素酸水溶液と海水との反応における海水の
使用量は、珪弗化水素酸に対する塩化ナトリウムのモル
比が1.5〜2.5の範囲になるようにするのが望まし
く、中でも20〜2.3が好適である。Next, it is desirable that the amount of seawater used in the reaction between the hydrosilicofluoric acid aqueous solution and seawater is such that the molar ratio of sodium chloride to hydrosilicofluoric acid is in the range of 1.5 to 2.5. Among them, 20 to 2.3 is preferable.
モル比が1.5未満では弗素回収率の著しい低下を招き
、モル比2.5以上では得られる珪弗化ソーダの純度が
低下して、製品としての価値が乏しくなると共に珪弗化
ソーダの回収率も低下する。If the molar ratio is less than 1.5, the fluorine recovery rate will drop significantly, and if the molar ratio is more than 2.5, the purity of the obtained sodium silifluoride will decrease, resulting in poor value as a product and the loss of the sodium silifluoride. The recovery rate also decreases.
このモル比造加による珪弗化ソーダの純度低下は、海水
中に含まれる塩化ナトリウム分以外の不純物分の影響に
よるものと考えられる。The decrease in the purity of sodium silicofluoride due to this molar ratio addition is considered to be due to the influence of impurities other than sodium chloride contained in seawater.
使用する海水は懸濁物が無ければよく、格別他に条件は
ない。The seawater used only needs to be free of suspended matter, and there are no other special requirements.
珪弗化水素酸と塩化ナトIJウムとの反応は比較的速や
かに進行するので反応時間は5分以下で充分であるが、
反応時間の延長による弊害はなく、また反応温度も常温
〜70℃程度であれば得られる珪弗化ソーダは純度が9
8.5%以上で粒子径も20〜60μ程度の高品質のも
のが得られる。The reaction between hydrofluorosilicic acid and sodium chloride proceeds relatively quickly, so a reaction time of 5 minutes or less is sufficient.
There is no harm caused by prolonging the reaction time, and if the reaction temperature is between room temperature and 70°C, the resulting sodium silicofluoride will have a purity of 9.
At 8.5% or more, high quality particles with a particle size of about 20 to 60 μm can be obtained.
このようにして生成した珪弗化ソーダは遠心分離、濾過
等で固液分離した後乾燥するという方法で製品とするこ
とが出来る。The sodium silicofluoride thus produced can be made into a product by separating solid and liquid by centrifugation, filtration, etc., and then drying it.
一方炉液は溶存する少量の弗素分を石灰乳等カルシウム
化合物で凝集、中和、沈澱等を行なう従来公知の方法で
容易に処理することが出来る。On the other hand, the furnace liquid can be easily treated by conventionally known methods in which a small amount of dissolved fluorine is coagulated, neutralized, or precipitated with a calcium compound such as milk of lime.
従来の弗素含有排ガスの処理方法は、多くの場合、石灰
乳、苛性ソーダなどの有用な原料を使用して弗素分を利
用価値のない産業廃棄物とする方法であったが、本発明
の方法は、上記のような原料を使用することなく、単に
海水と反応させるだけで、弗素含有排ガスの処理を兼ね
、高品質の珪弗化ソーダを得るというものであって、そ
の工業的な有用性は極めて大きいものである。Conventional methods for treating fluorine-containing exhaust gas often use useful raw materials such as milk of lime and caustic soda to turn the fluorine content into industrial waste with no use value, but the method of the present invention , it is possible to obtain high-quality sodium silicofluoride by simply reacting it with seawater without using the above-mentioned raw materials, which also serves as a treatment for fluorine-containing exhaust gas, and its industrial usefulness is It is extremely large.
以下、本発明を実施例及び比較例により具体的に説明す
る。Hereinafter, the present invention will be specifically explained with reference to Examples and Comparative Examples.
尚、実施例、比較例において%及び麻は夫々重量基準を
示す。In addition, in Examples and Comparative Examples, % and linen are based on weight, respectively.
実施例 1
有効容積12001の攪拌機付反応槽に、氷晶石製造の
際の排ガスを水に吸収させて得られた表−1に示す組成
の珪弗化水素酸水溶液100kgと清澄な海水(塩化ナ
トリウム濃度21.1 g/l )を8701加え、温
度50℃にて反応させた後、回転真空濾過機にて濾過後
乾燥して純度99.6%、粒径30〜60μの珪弗化ソ
ーダを20.4kg得た。Example 1 100 kg of a hydrosilicofluoric acid aqueous solution having the composition shown in Table 1 obtained by absorbing exhaust gas during cryolite production into water and clear seawater (chlorinated After adding 8,701 ml of sodium (concentration: 21.1 g/l) and reacting at a temperature of 50°C, it was filtered with a rotary vacuum filter and dried to obtain sodium fluorosilicide with a purity of 99.6% and a particle size of 30 to 60μ. 20.4 kg of was obtained.
実施例 2
実施例1と同じ珪弗化水素酸水溶液100kgに水を1
00kg加え稀釈した以外は実施例1と全く同様な操作
を行なった。Example 2 Add 1 part of water to 100 kg of the same hydrosilicofluoric acid aqueous solution as in Example 1.
The same operation as in Example 1 was performed except that 00 kg was added and diluted.
得られた珪弗化ソーダは純度99.5%、粒径30〜6
0μであり、収量は18.1kgであった。The obtained sodium silicofluoride has a purity of 99.5% and a particle size of 30 to 6.
The yield was 18.1 kg.
比較例 1
反応槽を有効容積18001、海水量を14004に変
更した以外は実施例1と全く同様の操作を行ない15.
1kgの珪弗化ソーダを得たが、純度は98.1%と悪
化してJIS規格値(98,5%以上)をも維持出来な
く、粒径も20〜40μと低下し且つ収量も低下した。Comparative Example 1 The same operation as in Example 1 was carried out except that the effective volume of the reaction tank was changed to 18001 and the seawater volume was changed to 14004.15.
Although 1 kg of sodium silicofluoride was obtained, the purity deteriorated to 98.1% and the JIS standard value (98.5% or more) could not be maintained, the particle size decreased to 20 to 40μ, and the yield also decreased. did.
比較例 2
湿式燐酸濃縮工程に於いて発生した弗素含有排ガスを水
に吸収させた溶液を分析したところ、弗素分(Fとして
)16.7%、珪素分(SiO□として)5.1%であ
った。Comparative Example 2 A solution obtained by absorbing fluorine-containing exhaust gas generated in the wet phosphoric acid concentration process in water was analyzed and found that the fluorine content (as F) was 16.7% and the silicon content (as SiO□) was 5.1%. there were.
この液100kgを用いて清澄な海水1000G塩化ナ
トリウム分21.:l/l)を加え温度40℃にて、反
応、濾過、乾燥し、純度98.1%、粒径20〜40μ
の珪弗化ソーダを9.8 kg得た。Using 100kg of this liquid, clear seawater 1000G sodium chloride content 21. :l/l) and reacted at a temperature of 40℃, filtered, and dried to obtain a mixture with a purity of 98.1% and a particle size of 20-40μ.
9.8 kg of sodium silicofluoride was obtained.
実施例 3
比較例2と同じ弗素含有排ガス吸収液に活性シリカとし
て珪ソウ土を添加し、再び分析したところF16.6%
、S t 028.5%であった。Example 3 Diatomaceous earth was added as activated silica to the same fluorine-containing exhaust gas absorption liquid as in Comparative Example 2, and analysis was performed again to find F16.6%.
, S t 028.5%.
この液を用いて、比較例2と同様の条件下にて反応、濾
過、乾燥を行い、純度99.5%、粒径30〜60μの
珪弗化ソーダを21.2kg得た。Using this liquid, reaction, filtration, and drying were performed under the same conditions as in Comparative Example 2 to obtain 21.2 kg of sodium silicofluoride with a purity of 99.5% and a particle size of 30 to 60 μm.
比較例 3
実施例1と同じ珪弗化水素酸水溶液100kgに水を2
50kg加え稀釈した以外は、実施例1と全く同様な操
作を行った。Comparative Example 3 Add 2 ml of water to 100 kg of the same hydrosilicic acid aqueous solution as in Example 1.
The same operation as in Example 1 was performed except that 50 kg was added and diluted.
得られた珪弗化ソーダは純度98.0%、粒径10〜2
5μであり収量は14.9kgであった。The obtained sodium silicofluoride had a purity of 98.0% and a particle size of 10 to 2.
The yield was 14.9 kg.
比較例 4
実施例1と同じ珪弗化水素酸水溶液を濃縮し表−2の組
成の液を得た、該液50kgと清澄な海水(塩化ナトリ
ウム濃度21.1 g/l )を8701加え、実施例
1と同様、反応、濾過、乾燥を行ったところ得られた珪
弗化ソーダの純度は97.8%、粒径5〜10μであり
収量は20.1 kgであった。Comparative Example 4 The same aqueous hydrosilicofluoric acid solution as in Example 1 was concentrated to obtain a liquid having the composition shown in Table 2. 50 kg of this liquid and 870 kg of clear seawater (sodium chloride concentration 21.1 g/l) were added. As in Example 1, the reaction, filtration, and drying were carried out, and the purity of the sodium silicofluoride obtained was 97.8%, the particle size was 5 to 10 μm, and the yield was 20.1 kg.
実施例 4
表2の液50kgに水35kyを加え稀釈した以外は比
較例4と全く同様な操作を行った。Example 4 The same operation as in Comparative Example 4 was performed except that 50 kg of the liquid shown in Table 2 was diluted by adding 35 ky of water.
得られた珪弗化ソーダは純度99.4%、粒径30〜6
0であり収量は20.4kgであった。The obtained sodium silicofluoride has a purity of 99.4% and a particle size of 30 to 6.
0, and the yield was 20.4 kg.
Claims (1)
液とした後、該珪弗化水素酸と塩化ナトリウムとを反応
させて珪弗化ソーダを製造する方法において、珪弗化水
素酸水溶液の濃度を10〜30重量%とし、塩化ナトリ
ウム源として海水を、該海水中の塩化ナトリウムが、珪
弗化水素酸1モルに対し1.5〜2.5モルきなるよう
な量で使用することを特徴とする弗素含有排ガスからの
珪弗化ソーダの製造方法。1. In a method for producing sodium silicofluoride by absorbing fluorine-containing exhaust gas into water to form an aqueous solution of hydrosilicofluoric acid and then reacting the hydrofluoric acid with sodium chloride, the method comprises: The concentration of sodium chloride is 10 to 30% by weight, and seawater is used as a sodium chloride source in an amount such that sodium chloride in the seawater is 1.5 to 2.5 mol per 1 mol of hydrosilicofluoric acid. A method for producing sodium silicofluoride from fluorine-containing exhaust gas, characterized in that:
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP3249981A JPS5934131B2 (en) | 1981-03-09 | 1981-03-09 | Method for producing silicofluoride soda from fluorine-containing exhaust gas |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP3249981A JPS5934131B2 (en) | 1981-03-09 | 1981-03-09 | Method for producing silicofluoride soda from fluorine-containing exhaust gas |
Publications (2)
Publication Number | Publication Date |
---|---|
JPS57149816A JPS57149816A (en) | 1982-09-16 |
JPS5934131B2 true JPS5934131B2 (en) | 1984-08-20 |
Family
ID=12360680
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
JP3249981A Expired JPS5934131B2 (en) | 1981-03-09 | 1981-03-09 | Method for producing silicofluoride soda from fluorine-containing exhaust gas |
Country Status (1)
Country | Link |
---|---|
JP (1) | JPS5934131B2 (en) |
Families Citing this family (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
KR100256914B1 (en) * | 1997-11-03 | 2000-05-15 | 최상원 | Method for preparing crystalline compound having mesoporous structure |
JP5495392B2 (en) * | 2011-05-24 | 2014-05-21 | 森田化学工業株式会社 | Method for producing valuable materials from waste liquid |
-
1981
- 1981-03-09 JP JP3249981A patent/JPS5934131B2/en not_active Expired
Also Published As
Publication number | Publication date |
---|---|
JPS57149816A (en) | 1982-09-16 |
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