JPH06322402A - Method for separating and refining potassium fluoride - Google Patents
Method for separating and refining potassium fluorideInfo
- Publication number
- JPH06322402A JPH06322402A JP6359092A JP6359092A JPH06322402A JP H06322402 A JPH06322402 A JP H06322402A JP 6359092 A JP6359092 A JP 6359092A JP 6359092 A JP6359092 A JP 6359092A JP H06322402 A JPH06322402 A JP H06322402A
- Authority
- JP
- Japan
- Prior art keywords
- fluoride
- potassium
- tantalum
- salt
- potassium fluoride
- 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.)
- Granted
Links
- 239000011698 potassium fluoride Substances 0.000 title claims abstract description 70
- NROKBHXJSPEDAR-UHFFFAOYSA-M potassium fluoride Chemical compound [F-].[K+] NROKBHXJSPEDAR-UHFFFAOYSA-M 0.000 title claims abstract description 35
- 235000003270 potassium fluoride Nutrition 0.000 title claims abstract description 17
- 238000000034 method Methods 0.000 title claims description 18
- 238000007670 refining Methods 0.000 title abstract 2
- WCUXLLCKKVVCTQ-UHFFFAOYSA-M Potassium chloride Chemical compound [Cl-].[K+] WCUXLLCKKVVCTQ-UHFFFAOYSA-M 0.000 claims abstract description 75
- 150000003839 salts Chemical class 0.000 claims abstract description 73
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims abstract description 39
- 235000011164 potassium chloride Nutrition 0.000 claims abstract description 37
- 239000001103 potassium chloride Substances 0.000 claims abstract description 37
- APLLYCDGAWQGRK-UHFFFAOYSA-H potassium;hexafluorotantalum(1-) Chemical compound [F-].[F-].[F-].[F-].[F-].[F-].[K+].[Ta+5] APLLYCDGAWQGRK-UHFFFAOYSA-H 0.000 claims abstract description 12
- 239000006227 byproduct Substances 0.000 claims description 24
- 239000000706 filtrate Substances 0.000 claims description 16
- 229910052715 tantalum Inorganic materials 0.000 claims description 15
- GUVRBAGPIYLISA-UHFFFAOYSA-N tantalum atom Chemical compound [Ta] GUVRBAGPIYLISA-UHFFFAOYSA-N 0.000 claims description 15
- 238000007865 diluting Methods 0.000 claims description 13
- 239000011734 sodium Substances 0.000 claims description 13
- 239000002994 raw material Substances 0.000 claims description 11
- 229910052783 alkali metal Inorganic materials 0.000 claims description 9
- 150000001340 alkali metals Chemical class 0.000 claims description 9
- 238000010438 heat treatment Methods 0.000 claims description 8
- 239000000203 mixture Substances 0.000 claims description 8
- 239000011775 sodium fluoride Substances 0.000 claims description 6
- 238000001816 cooling Methods 0.000 claims description 4
- 229910052708 sodium Inorganic materials 0.000 claims description 4
- DGAQECJNVWCQMB-PUAWFVPOSA-M Ilexoside XXIX Chemical compound C[C@@H]1CC[C@@]2(CC[C@@]3(C(=CC[C@H]4[C@]3(CC[C@@H]5[C@@]4(CC[C@@H](C5(C)C)OS(=O)(=O)[O-])C)C)[C@@H]2[C@]1(C)O)C)C(=O)O[C@H]6[C@@H]([C@H]([C@@H]([C@H](O6)CO)O)O)O.[Na+] DGAQECJNVWCQMB-PUAWFVPOSA-M 0.000 claims description 3
- PUZPDOWCWNUUKD-UHFFFAOYSA-M sodium fluoride Chemical compound [F-].[Na+] PUZPDOWCWNUUKD-UHFFFAOYSA-M 0.000 claims 6
- 235000013024 sodium fluoride Nutrition 0.000 claims 3
- 150000004673 fluoride salts Chemical group 0.000 claims 1
- 229910052751 metal Inorganic materials 0.000 abstract description 5
- 239000002184 metal Substances 0.000 abstract description 5
- 238000004064 recycling Methods 0.000 abstract description 2
- 239000011833 salt mixture Substances 0.000 abstract 3
- KRHYYFGTRYWZRS-UHFFFAOYSA-M Fluoride anion Chemical compound [F-] KRHYYFGTRYWZRS-UHFFFAOYSA-M 0.000 abstract 1
- 230000005494 condensation Effects 0.000 abstract 1
- 238000009833 condensation Methods 0.000 abstract 1
- 238000001953 recrystallisation Methods 0.000 abstract 1
- 238000006722 reduction reaction Methods 0.000 description 19
- 239000013078 crystal Substances 0.000 description 18
- 238000006243 chemical reaction Methods 0.000 description 14
- FAPWRFPIFSIZLT-UHFFFAOYSA-M Sodium chloride Chemical compound [Na+].[Cl-] FAPWRFPIFSIZLT-UHFFFAOYSA-M 0.000 description 12
- 239000012535 impurity Substances 0.000 description 11
- 239000000843 powder Substances 0.000 description 11
- 239000000243 solution Substances 0.000 description 10
- 239000003990 capacitor Substances 0.000 description 6
- 239000011780 sodium chloride Substances 0.000 description 6
- 239000000126 substance Substances 0.000 description 6
- 239000003085 diluting agent Substances 0.000 description 4
- 239000011148 porous material Substances 0.000 description 4
- 238000003756 stirring Methods 0.000 description 4
- 239000007864 aqueous solution Substances 0.000 description 3
- 239000011575 calcium Substances 0.000 description 3
- 238000001914 filtration Methods 0.000 description 3
- 229910052742 iron Inorganic materials 0.000 description 3
- 238000002844 melting Methods 0.000 description 3
- 230000008018 melting Effects 0.000 description 3
- 238000000967 suction filtration Methods 0.000 description 3
- 239000007795 chemical reaction product Substances 0.000 description 2
- 230000007423 decrease Effects 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 229910021645 metal ion Inorganic materials 0.000 description 2
- 239000002245 particle Substances 0.000 description 2
- 239000002244 precipitate Substances 0.000 description 2
- 238000011084 recovery Methods 0.000 description 2
- 229910052710 silicon Inorganic materials 0.000 description 2
- 235000008733 Citrus aurantifolia Nutrition 0.000 description 1
- 229910020640 KF—NaF Inorganic materials 0.000 description 1
- ZLMJMSJWJFRBEC-UHFFFAOYSA-N Potassium Chemical compound [K] ZLMJMSJWJFRBEC-UHFFFAOYSA-N 0.000 description 1
- KEAYESYHFKHZAL-UHFFFAOYSA-N Sodium Chemical compound [Na] KEAYESYHFKHZAL-UHFFFAOYSA-N 0.000 description 1
- 235000011941 Tilia x europaea Nutrition 0.000 description 1
- 229910001508 alkali metal halide Inorganic materials 0.000 description 1
- 150000008045 alkali metal halides Chemical class 0.000 description 1
- 239000010407 anodic oxide Substances 0.000 description 1
- 229910052791 calcium Inorganic materials 0.000 description 1
- WUKWITHWXAAZEY-UHFFFAOYSA-L calcium difluoride Chemical compound [F-].[F-].[Ca+2] WUKWITHWXAAZEY-UHFFFAOYSA-L 0.000 description 1
- 229910001634 calcium fluoride Inorganic materials 0.000 description 1
- 239000003638 chemical reducing agent Substances 0.000 description 1
- 229910052804 chromium Inorganic materials 0.000 description 1
- 239000011362 coarse particle Substances 0.000 description 1
- 230000000052 comparative effect Effects 0.000 description 1
- 238000013329 compounding Methods 0.000 description 1
- 239000000498 cooling water Substances 0.000 description 1
- 238000005260 corrosion Methods 0.000 description 1
- 230000007797 corrosion Effects 0.000 description 1
- 238000004090 dissolution Methods 0.000 description 1
- 238000001035 drying Methods 0.000 description 1
- 239000010419 fine particle Substances 0.000 description 1
- XLYOFNOQVPJJNP-UHFFFAOYSA-M hydroxide Chemical compound [OH-] XLYOFNOQVPJJNP-UHFFFAOYSA-M 0.000 description 1
- 150000004679 hydroxides Chemical class 0.000 description 1
- 238000002955 isolation Methods 0.000 description 1
- 239000004571 lime Substances 0.000 description 1
- 229910052749 magnesium Inorganic materials 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 150000002739 metals Chemical class 0.000 description 1
- 238000002156 mixing Methods 0.000 description 1
- 229910052759 nickel Inorganic materials 0.000 description 1
- 229910052700 potassium Inorganic materials 0.000 description 1
- 239000011591 potassium Substances 0.000 description 1
- 238000000746 purification Methods 0.000 description 1
- 229920006395 saturated elastomer Polymers 0.000 description 1
- 238000000926 separation method Methods 0.000 description 1
- JHDVAGRZMNESMW-UHFFFAOYSA-H sodium;tantalum(5+);hexafluoride Chemical compound [F-].[F-].[F-].[F-].[F-].[F-].[Na+].[Ta+5] JHDVAGRZMNESMW-UHFFFAOYSA-H 0.000 description 1
- 239000007787 solid Substances 0.000 description 1
Classifications
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01D—COMPOUNDS OF ALKALI METALS, i.e. LITHIUM, SODIUM, POTASSIUM, RUBIDIUM, CAESIUM, OR FRANCIUM
- C01D3/00—Halides of sodium, potassium or alkali metals in general
- C01D3/02—Fluorides
Landscapes
- Chemical & Material Sciences (AREA)
- Organic Chemistry (AREA)
- Engineering & Computer Science (AREA)
- Materials Engineering (AREA)
- Inorganic Chemistry (AREA)
- Manufacture And Refinement Of Metals (AREA)
- Powder Metallurgy (AREA)
Abstract
Description
【０００１】[0001]
【産業上の利用分野】本発明はフッ化タンタルカリウム
をナトリウム還元する際に、希釈塩として使用するフッ
化カリウムに関し、特に還元工程で副生する混合塩を回
収精製して再使用する方法に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to potassium fluoride used as a diluting salt when sodium tantalum fluoride is reduced, and more particularly to a method for recovering and purifying a mixed salt produced as a by-product in the reduction step and reusing it. .
【０００２】[0002]
【従来の技術】タンタル（Ｔａ）は融点が約３０００℃
と高く、耐熱性にすぐれており化学的安定性にもすぐれ
ているので、各種耐熱耐食材料として使用されている。
また、表面に安定した陽極酸化皮膜を作り、その皮膜の
誘電率がきわめて高いことを利用して、焼結形タンタル
コンデンサとして利用されている。タンタルは通常フッ
化タンタルカリウム（Ｋ2 Ｔa Ｆ7 ）をナトリウム（Ｎ
ａ）やカリウム（Ｋ）等のアルカリ金属を用いて還元す
る方法により得られる。その還元反応は次の反応式によ
る。 Ｋ2 Ｔa Ｆ7 ＋５Ｎａ → Ｔａ＋２ＫＦ＋５ＮａＦ ‥‥‥（１） この反応はＫ2 Ｔa Ｆ7 が所定の温度（６００〜９００
℃）に達した時点で金属ナトリウムを接触させると反応
を開始し、反応の進行に伴って反応熱によって浴温が１
０００℃前後の高温に達する。その結果生成タンタル粒
子が成長したり、あるいは相互に焼結して粗い粒子にな
ってしまい、コンデンサ用としては不適当なものとな
る。また、金属ナトリウムを均一にＫ2 Ｔa Ｆ7 に接触
させることができなかったり、生成タンタルメタルと副
生混合塩との分離が困難となることから、収率が低下す
るという困難を伴う。2. Description of the Related Art Tantalum (Ta) has a melting point of about 3000.degree.
It is used as various heat and corrosion resistant materials because of its high heat resistance and excellent chemical stability.
Further, a stable anodic oxide film is formed on the surface, and the fact that the film has a very high dielectric constant is used as a sintered tantalum capacitor. Tantalum is usually potassium tantalum fluoride (K 2 Ta F 7 ) and sodium (N 2
It is obtained by a method of reduction using an alkali metal such as a) or potassium (K). The reduction reaction is based on the following reaction formula. K 2 T a F 7 + 5Na → Ta + 2KF + 5NaF ‥‥‥ (1) This reaction is K 2 T a F 7 a predetermined temperature (600 to 900
(° C), the reaction starts when the metallic sodium is contacted, and the bath temperature becomes 1 due to the heat of reaction as the reaction progresses.
Reach high temperatures around 000 ° C. As a result, the generated tantalum particles grow or sinter each other into coarse particles, which is unsuitable for capacitors. Further, it is difficult to uniformly contact the sodium metal with K 2 Ta F 7 or it becomes difficult to separate the produced tantalum metal and the by-produced mixed salt, which causes a problem that the yield decreases.
【０００３】このため上記還元反応に際し、フッ化カリ
ルム（ＫＦ）、塩化カリウム（ＫＣｌ）、塩化ナトリウ
ム（ＮａＣｌ）等のアルカリ金属のハロゲン化物を希釈
塩として使用することが提案されている（特開昭４８−
４３００６号、特開昭６２−２７８２１０号公報参
照）。希釈塩を使用する場合は浴温度を７６０〜８５０
℃と低くしてもなお流動性が良好で、生成タンタルと副
生混合塩との分離も容易で収率が高く、かつ生成したタ
ンタルも微細粒子となりコンデンサ用として好適なもの
となる。希釈塩を使用することの効果は大きいものの、
副生する混合塩の量も増大しその処理が問題となるが、
現状では大量の水を加えて溶解し、石灰を加えてフッ化
カルシウムとして固定して処理しているのみで、有効な
再利用の方法も見出されていない。Therefore, it has been proposed to use an alkali metal halide such as potassium fluoride (KF), potassium chloride (KCl) or sodium chloride (NaCl) as a diluting salt in the above reduction reaction (Japanese Patent Application Laid-Open No. 2000-242242). 48-
No. 43006, JP-A-62-278210). If using dilute salt, the bath temperature should be 760-850.
Even if the temperature is as low as ℃, the fluidity is still good, the separation of the produced tantalum and the by-product mixed salt is easy and the yield is high, and the produced tantalum becomes fine particles, which is suitable for capacitors. Although the effect of using diluted salt is great,
The amount of mixed salt produced as a by-product also increases and its treatment becomes a problem,
At present, a large amount of water is added to dissolve it, and lime is added to fix it as calcium fluoride for treatment, and no effective recycling method has been found.
【０００４】[0004]
【発明が解決しようとする課題】希釈塩としてたとえば
ＫＦとＫＣｌを用いる場合の反応式は次式による。 Ｋ2 Ｔa Ｆ7 ＋５Ｎａ＋ｍｋＦ＋ｎＫＣｌ → Ｔａ＋（２＋ｍ）ＫＦ＋ｎＫＣｌ＋５ＮａＦ ‥‥‥（２） 希釈塩はＫＦ、ＫＣｌ、ＮａＣｌをそれぞれ単独又は混
合して用いる。ここで希釈塩として使用するＫＦまたは
ＫＣｌの量ｍ、ｎはＫＦ単独使用の場合、ｍは重量比で
原料Ｋ2 Ｔa Ｆ7 量の０．２〜２．５倍（モル比では
１．４〜１６．９倍）、ＫＦとＫＣｌを併用する場合、
ｍは重量比でＫ2 Ｔa Ｆ7 量の０．２〜２．５倍（モル
比では１．４〜１６．９倍）、ｎは３．０倍以下（モル
比で１５．８倍以下）の範囲で使用される。希釈塩の使
用量が多く、副生混合塩の発生量も多くなってくると原
料コストの上昇要因となることに加え、副生する混合塩
の処理も大きな問題となる。（２）式の反応を見ると、
希釈塩として加えたＫＦとＫＣｌの混合塩中に還元で生
じたＫＦとＮａＦが混合していく形態となっている。こ
の副生混合塩からＮａＦを分離除去できれば、希釈塩と
して使用できる。The reaction equation when using, for example, KF and KCl as the diluting salt is as follows. K 2 T a F 7 + 5Na + mkF + nKCl → Ta + (2 + m) KF + nKCl + 5NaF ‥‥‥ (2) diluting salt is KF, KCl, used respectively NaCl alone or in combination. Here, the amounts m and n of KF or KCl used as a diluting salt are 0.2 to 2.5 times the amount of the raw material K 2 Ta F 7 in a weight ratio (m. 4 to 16.9 times), when using KF and KCl together,
m is 0.2 to 2.5 times the K 2 T a F 7 weight in a weight ratio (from 1.4 to 16.9 times in mole ratio), 15.8 times n is 3.0 times or less (molar ratio The following is used in the range. When the amount of the diluted salt used is large and the amount of the mixed salt produced as a by-product is large, the raw material cost is increased, and the treatment of the mixed salt produced as a by-product becomes a serious problem. Looking at the reaction of equation (2),
It is a form in which KF and NaF produced by reduction are mixed in a mixed salt of KF and KCl added as a diluted salt. If NaF can be separated and removed from this by-product mixed salt, it can be used as a diluted salt.
【０００５】ところが、原料Ｋ2 Ｔa Ｆ7 中には不純物
としてＦｅ、Ｎｉ、Ｃｒ、Ｃａ、Ｍｇ、Ｓｉ等が含まれ
ており、これらは副生混合塩中に移行する。上記不純物
はコンデンサ用タンタルにとっては有害元素であり、希
釈塩中の含有量も極力低いものでなければならない。従
来、不純物金属を含むＫＦとＮａＦとの混合塩、あるい
はＫＦとＫＣｌとＮａＦとの混合塩から、高純度のＫＦ
あるいはＫＦ及びＫＣｌを分離する有効な手段は無く、
ましてやタンタル還元工程から発生する混合塩を分離精
製して再利用する手段は知られていない。本発明は上記
事情に鑑みなされてものであって、Ｋ2 Ｔa Ｆ7 のアル
カリ金属還元によって副生する混合塩を分離精製して再
利用する効果的な手段を提供しようとするものである。However, the raw material K 2 Ta F 7 contains Fe, Ni, Cr, Ca, Mg, Si and the like as impurities, and these are transferred to the by-product mixed salt. The above impurities are harmful elements for tantalum for capacitors, and the content in the diluted salt must be as low as possible. Conventionally, a mixed salt of KF and NaF containing an impurity metal or a mixed salt of KF, KCl and NaF is used to obtain high purity KF.
Or there is no effective means to separate KF and KCl,
Furthermore, there is no known means for separating and purifying the mixed salt generated from the tantalum reduction step and reusing it. The present invention has been made in view of the above circumstances, and it is an object of the present invention to provide an effective means for separating and purifying a mixed salt by-produced by the alkali metal reduction of K 2 Ta F 7 and reusing it. .
【０００６】[0006]
【課題を解決するための手段】前記課題を解決するた
め、本発明ではＫ2 Ｔa Ｆ7 をアルカリ金属還元して得
られる副生塩を、副生塩中のＫＦまたはＫＦとＫＣｌが
溶解するに必要な量以下の水に溶解して濾過し、濾液を
加熱濃縮して冷却後に晶出するＫＦまたはＫＦとＫＣｌ
を、再びＫ2 Ｔa Ｆ7 の還元工程の希釈塩として使用す
ることとした。In order to solve the above-mentioned problems, in the present invention, KF or KF and KCl in the by-product salt are dissolved in a by-product salt obtained by reducing K 2 Ta F 7 with an alkali metal. KF or KF and KCl, which are dissolved in water in an amount not more than that required for filtration and filtered, and the filtrate is heated and concentrated and crystallized after cooling
And it was to be used again as diluent salt reduction step of K 2 T a F 7.
【０００７】本発明の副生混合塩は、フッ化タンタルカ
リウムをアルカリ金属還元した結果発生したものであっ
て、前記（１）式で示されるＫＦとＮａＦとの混合物あ
るいは（２）式で示されるＫＣｌの加わったものであ
る。主要組成はＫＦ：１２〜８５wt％、ＫＣｌ：７５wt
％以下、残ＮａＦからなり、これに不純物金属や水分を
含んでいる。水分は反応終了後水冷却するためである。
不純物としては、Ｆｅ：１０ppm 、Ｎｉ：５ppm 、Ｃ
ｒ：４ppm 、Ｃａ：６０ppm 、Ｍｇ：１ppm 、Ｂ：１pp
m 、Ｓｉ：３０ppm 程度が含まれている。主要組成は上
記の他にＮａＣｌが含まれる場合もある。通常還元反応
がバッチ操業で行われるので、副成混合塩は冷却された
固形物として得られる。副生混合塩の成分のうち、Ｋ
Ｆ、ＫＣｌ、ＮａＣｌ等は水に対してかなりの溶解度を
持っているのに対し、ＮａＦの溶解度はきわめて小さ
い。ＫＦ、ＫＣｌ、ＮａＦの各温度の溶解度は表１の通
りである。The by-product mixed salt of the present invention is produced as a result of alkali metal reduction of potassium tantalum fluoride, and is a mixture of KF and NaF represented by the above formula (1) or represented by the formula (2). KCl is added. Main composition is KF: 12-85wt%, KCl: 75wt%
% Or less, it consists of residual NaF, which contains impurity metals and water. Water is for cooling water after the reaction is completed.
As impurities, Fe: 10 ppm, Ni: 5 ppm, C
r: 4 ppm, Ca: 60 ppm, Mg: 1 ppm, B: 1 pp
m, Si: about 30 ppm is included. In addition to the above, the main composition may include NaCl. Since the reduction reaction is usually performed in a batch operation, the by-product mixed salt is obtained as a cooled solid. Among the components of the by-product mixed salt, K
F, KCl, NaCl, etc. have a considerable solubility in water, whereas NaF has a very low solubility. The solubilities of KF, KCl and NaF at each temperature are shown in Table 1.
【０００８】[0008]
【表１】 [Table 1]
【０００９】実際の副生塩は２〜３成分が共存してお
り、不純物金属も含んでいるため、４０℃における水に
対する溶解度はＫＦ−ＮａＦ系ではＫＦ：６０wt％、Ｎ
ａＦ：１０ppm 以下、ＫＦ−ＫＣｌ−ＮａＦ系ではＫ
Ｆ：５２wt％、ＫＣｌ：６wt％、ＮａＦ：１０ppm 以下
となる。本発明では副生塩中のＫＦ及びＫＣｌのみが溶
解するのに必要な量以下の水を使用し、ＮａＦを不溶残
渣として除去するものである。この場合、ＫＦ及びＫＣ
ｌのみが溶解する水の量は表１に示す各成分の溶解度に
基づいて決定する。水の量が少ない場合は未溶解のＫＦ
やＫＣｌが残り、回収率が低下するが純度は高くなる。
水の量が多い場合はＮａＦの混入量が増えてくる。従っ
て本発明ではＫＦ及びＫＣｌが溶解するのに必要な理論
水量を上限としてそれ以下の水量を使用し、回収後のＫ
Ｆ及びＫＣｌの純度を確保することとした。The actual by-product salt coexists with a few components and also contains an impurity metal. Therefore, the solubility in water at 40 ° C. is KF: 60 wt%, N in the KF-NaF system.
aF: 10 ppm or less, K in KF-KCl-NaF system
F: 52 wt%, KCl: 6 wt%, NaF: 10 ppm or less. In the present invention, water is used in an amount equal to or less than the amount required to dissolve only KF and KCl in the by-product salt, and NaF is removed as an insoluble residue. In this case, KF and KC
The amount of water in which only 1 is dissolved is determined based on the solubility of each component shown in Table 1. Undissolved KF when the amount of water is small
And KCl remain and the recovery rate decreases, but the purity increases.
When the amount of water is large, the amount of NaF mixed in increases. Therefore, in the present invention, the theoretical amount of water necessary for KF and KCl to dissolve is used as an upper limit, and the amount of water less than that is used.
It was decided to ensure the purity of F and KCl.
【００１０】溶解する水の温度はＫＦの溶解度が高くな
る１７℃以上が良い。ＫＦの溶解度は４５℃以上では飽
和してしまうので、あまり高温で溶解させても効果に乏
しく、かえって不純物の混入を招く。したがって溶解温
度は１７〜４５℃、好ましくは２５〜４０℃とする。溶
解中の水溶液のpHは１２〜１４のアルカリ性とする。通
常は副生塩中の未反応Ｎａによってアルカリ性が保たれ
るが、未反応Ｎａが少ない場合はpH調整する必要があ
る。アルカリ性水溶液中では不純物金属イオンが存在す
る場合は不溶性水酸化物となり、後続の濾過処理によっ
て残渣として分離除去できる。The temperature of water to be dissolved is preferably 17 ° C. or higher at which the solubility of KF becomes high. Since the solubility of KF is saturated at 45 ° C. or higher, even if it is dissolved at an excessively high temperature, the effect is poor, and rather impurities are mixed. Therefore, the melting temperature is 17 to 45 ° C, preferably 25 to 40 ° C. The pH of the aqueous solution during dissolution should be 12-14 alkaline. Usually, the alkalinity is maintained by the unreacted Na in the by-product salt, but when the amount of unreacted Na is small, it is necessary to adjust the pH. When an impurity metal ion is present in an alkaline aqueous solution, it becomes an insoluble hydroxide and can be separated and removed as a residue by the subsequent filtration treatment.
【００１１】ＮａＦも未溶解残渣となる。この溶液を濾
過し、濾液を加熱濃縮して水分を減少させたのち、室温
附近まで冷却してＫＦ又はＫＦとＫＣｌの結晶を晶出さ
せ、再び濾過して結晶を分離回収する。このようにして
得られたＫＦ又はＫＦとＫＣｌの結晶は極めて高純度と
なる。NaF also becomes an undissolved residue. The solution is filtered, and the filtrate is concentrated by heating to reduce the water content, and then cooled to around room temperature to crystallize KF or KF and KCl crystals, which is filtered again to separate and collect the crystals. The crystals of KF or KF and KCl thus obtained have extremely high purity.
【００１２】次に回収したＫＦ又はＫＦとＫＣｌの結晶
を乾燥し、新たなＫ2 Ｔa Ｆ7 の還元工程の希釈塩とし
て使用する。還元反応は前記（２）式に従う。ここで希
釈塩はＫＦ単独でも良いし、ＫＦとＫＣｌを共用しても
良い。さらにＮａＣｌを併用しても良い。使用成分や使
用量が多くなる程、反応浴の融点が下がり操業が容易に
なる。しかし、還元生成するＴａの粒径、比表面積等の
粉末特性は反応温度に影響されるので、それらを考慮し
て希釈塩を選択する。Next, the recovered KF or the crystals of KF and KCl are dried and used as a diluted salt in a new reduction step of K 2 T a F 7 . The reduction reaction follows the equation (2). Here, the diluted salt may be KF alone or KF and KCl may be shared. Further, NaCl may be used together. The more components and amounts used, the lower the melting point of the reaction bath and the easier the operation. However, the powder properties such as the particle size and specific surface area of Ta produced by reduction are affected by the reaction temperature, and therefore the diluent salt is selected in consideration of them.
【００１３】希釈塩の量は原料となるＫ2 Ｔa Ｆ7 の量
を基準とし、ＫＦ単独の場合はＫ2Ｔa Ｆ7 量の０．２
〜２．５倍（重量比、以下同じ）、ＫＦとＫＣｌを併用
する場合はＫＦ量はＫ2 Ｔa Ｆ7 量の０．２〜２．５
倍、ＫＣｌ量は３．０倍以下が適当である。希釈塩の添
加方法はＫ2 Ｔa Ｆ7 と混合しても良く、Ｋ2 Ｔa Ｆ7
と交互に供給しても良く、あるいは希釈塩で隔離層を形
成し、その上からアルカリ金属還元剤を加える等公知の
方法が使用できる。回収希釈塩に加えて新規な希釈塩を
使用することはもちろん支障はない。その他還元条件は
公知の方法に従えば良い。The amount of the diluting salt is based on the amount of K 2 T a F 7 used as a raw material, and when KF is used alone, the amount of K 2 T a F 7 is 0.2.
2.5 times 0.2 to 2.5 (weight ratio, hereinafter the same), KF amount when used in combination KF and KCl is K 2 T a F 7 weight
It is suitable that the amount of KCl is 3.0 times or less. The method of adding the diluent salt may be mixed with K 2 T a F 7, K 2 T a F 7
Alternatively, a known method such as forming an isolation layer with a diluted salt and adding an alkali metal reducing agent thereto can be used. Of course, there is no problem in using a new diluted salt in addition to the recovered diluted salt. Other reducing conditions may be in accordance with a known method.
【００１４】[0014]
【作用】本発明はＫ2 Ｔa Ｆ7 をアルカリ金属還元して
得られる副生の混合塩を、水に対する溶解度差を利用し
て分離精製し、得られた高純度のＫＦ又はＫＦとＫＣｌ
の結晶を、Ｋ2 Ｔa Ｆ7 のアルカリ金属還元工程の希釈
塩として使用するものである。副生塩の精製工程では水
溶液のpHを１２〜１４のアルカリ性に保つことにより、
不純物金属イオンを水に不溶の水酸化物として除去でき
ることを利用したものである。According to the present invention, the by-product mixed salt obtained by reducing K 2 T a F 7 with an alkali metal is separated and purified by utilizing the difference in solubility in water, and the obtained high-purity KF or KF and KCl are obtained.
Is used as a diluting salt in the alkali metal reduction step of K 2 Ta F 7 . By maintaining the pH of the aqueous solution at 12 to 14 in the by-product salt purification step,
It utilizes the fact that impurity metal ions can be removed as hydroxides insoluble in water.
【００１５】[0015]
【実施例】本発明の実施例を示して具体的に説明する。 実施例１ Ｋ2 Ｔa Ｆ7 をＮａ還元してＴａ粉末を製造する際に副
生するＫＦとＮａＦを主成分とする混合塩を破砕し、１
０００重量部に４０℃の水１０００重量部を加えて、水
温を４０℃に維持しながら２２時間撹拌溶解した。溶液
のpHは１３．２であった。混合塩の化学分析値を表２に
示す。EXAMPLES The present invention will be specifically described with reference to examples. Example 1 K 2 T a F 7 were crushed mixed salt mainly composed of KF and NaF by-produced during the production of Ta powder with Na reduced, 1
1000 parts by weight of water at 40 ° C. was added to 000 parts by weight, and dissolved by stirring for 22 hours while maintaining the water temperature at 40 ° C. The pH of the solution was 13.2. The chemical analysis values of the mixed salt are shown in Table 2.
【００１６】[0016]
【表２】 [Table 2]
【００１７】この溶液を吸引濾過し、残渣３５１重量部
と濾液１６４１重量部を得た。化学分析の結果、残渣は
ＮａＦ：９１．６％、ＫＦ：７．６％、水分：０．７％
であった。濾液を孔径１μm の濾紙にて濾過した後、加
熱濃縮して８３２重量部となる迄水分を蒸発させた後、
２５℃まで冷却して１時間保持し結晶を晶出させた。再
度吸引濾過して５２１重量部の白色結晶と２８０重量部
の濾液を得た。白色結晶の乾燥後の分析値を表２に示
す。濾液中には４４．０％のＫＦが含まれていた。The solution was suction filtered to obtain 351 parts by weight of the residue and 1641 parts by weight of the filtrate. As a result of chemical analysis, the residue was NaF: 91.6%, KF: 7.6%, water content: 0.7%.
Met. The filtrate was filtered through a filter paper with a pore size of 1 μm, and then concentrated by heating to evaporate the water content to 832 parts by weight.
It was cooled to 25 ° C. and kept for 1 hour to crystallize crystals. Suction filtration was carried out again to obtain 521 parts by weight of white crystals and 280 parts by weight of filtrate. The analytical values of the white crystals after drying are shown in Table 2. The filtrate contained 44.0% KF.
【００１８】次に、この回収ＫＦを利用してＫ2 Ｔa Ｆ
7 のＮａ還元を行った。還元方法は反応容器に原料Ｋ2
Ｔa Ｆ7 及び回収ＫＦを投入した後、容器内をＡｒガス
で置換した。原料の使用割合を表３に示す。Next, using this recovered KF, K 2 T a F
Na reduction of 7 was performed. The reduction method is to use the raw material K 2
After introducing T a F 7 and recovered KF, the inside of the container was replaced with Ar gas. Table 3 shows the usage ratio of the raw materials.
【００１９】[0019]
【表３】 [Table 3]
【００２０】次いで反応容器内を８００℃にした後、容
器内を撹拌しながらＮａを添加した。すべてのＮａ添加
が終わった時点で、容器内の温度は反応熱により８８０
℃となった。Ｋ2 Ｔa Ｆ7 とＮａとの反応によりＴａ粉
末と新たなＫＦ、ＮａＦとが得られた。反応終了後冷却
し、容器から反応生成物を取り出し、Ｔａ粉末の沈殿層
とＫＦ、ＮａＦの層を機械的に分離し、Ｔａ粉末の沈殿
層を水洗、酸洗および乾燥してＴａ粉末を得た。得られ
たＴａ粉末の特性と収率を表３に示す。Next, after the inside of the reaction vessel was heated to 800 ° C., Na was added while stirring the inside of the vessel. At the end of all Na addition, the temperature in the container was 880 due to the heat of reaction.
It became ℃. K 2 T a F 7 and Na and Ta powder and the new KF by reaction, and the NaF was obtained. After completion of the reaction, the reaction product is cooled, the reaction product is taken out from the container, the Ta powder precipitate layer and the KF and NaF layers are mechanically separated, and the Ta powder precipitate layer is washed with water, pickled and dried to obtain Ta powder. It was Table 3 shows the characteristics and yield of the obtained Ta powder.
【００２１】実施例２ Ｋ2 Ｔa Ｆ7 をＮａ還元してＴａ粉末を製造する際に副
生するＫＦとＫＣｌとＮａＦとを主成分とする混合塩を
破砕し、１０００重量部に４０℃の水６５０重量部を加
えて、水温を４０℃に維持しながら２４時間撹拌溶解し
た。溶液のpHは１３．１であった。混合塩の化学分析値
を表２に示す。Example 2 K 2 T a F 7 was reduced with Na to produce Ta powder, and a mixed salt containing KF, KCl and NaF as main components, which was a by-product, was crushed and added to 1000 parts by weight at 40 ° C. 650 parts by weight of water was added and the solution was stirred and dissolved for 24 hours while maintaining the water temperature at 40 ° C. The pH of the solution was 13.1. The chemical analysis values of the mixed salt are shown in Table 2.
【００２２】この溶液を吸引濾過し、残渣４８０重量部
と濾液１１５８重量部を得た。化学分析の結果、残渣は
ＮａＦ：８８．８％、ＫＣｌ：９．６％、ＫＦ：１．０
％、水分：０．６％であった。濾液を孔径１μm の濾紙
にて濾過した後、加熱濃縮して４７６重量部となる迄水
分を蒸発させた後、２５℃まで冷却して１時間保持し結
晶を晶出させた。再度吸引濾過して４７２重量部の白色
結晶を得た。乾燥後の白色結晶の分析値を表２に示す。The solution was suction filtered to obtain 480 parts by weight of the residue and 1158 parts by weight of the filtrate. As a result of chemical analysis, the residue was NaF: 88.8%, KCl: 9.6%, KF: 1.0.
%, Water content: 0.6%. The filtrate was filtered with a filter paper having a pore size of 1 μm, and then concentrated by heating to evaporate the water content to 476 parts by weight, then cooled to 25 ° C. and kept for 1 hour to crystallize crystals. Suction filtration was performed again to obtain 472 parts by weight of white crystals. Table 2 shows the analytical values of the dried white crystals.
【００２３】次に、この回収混合塩を希釈塩として使用
し、Ｋ2 Ｔa Ｆ7 のＮａ還元を実施した。操作方法は実
施例１と同様である。原料の配合割合とＴａ粉末の特性
及び回収率を表３に示す。Next, this recovered mixed salt was used as a diluting salt to carry out Na reduction of K 2 Ta F 7 . The operation method is the same as in the first embodiment. Table 3 shows the mixing ratio of the raw materials, the characteristics of the Ta powder, and the recovery rate.
【００２４】実施例３ ＫＦとＮａＦを主成分とする副生混合塩１０００重量部
に３０℃の水１０００重量部を加え、水温を３０℃に維
持しながら２２時間撹拌溶解した。溶液のpHは１３．１
であった。この溶液を吸引濾過し、残渣３８２重量部と
濾液１６１２重量部を得た。化学分析の結果、残渣はＮ
ａＦ：９３．０％、ＫＦ：６．０％、水分：０．７％で
あった。Example 3 1000 parts by weight of water at 30 ° C. was added to 1000 parts by weight of a by-produced mixed salt containing KF and NaF as main components, and dissolved by stirring for 22 hours while maintaining the water temperature at 30 ° C. The pH of the solution is 13.1
Met. The solution was suction filtered to obtain 382 parts by weight of the residue and 1612 parts by weight of the filtrate. As a result of chemical analysis, the residue is N
The aF was 93.0%, the KF was 6.0%, and the water was 0.7%.
【００２５】濾液を孔径１μm の濾紙にて濾過した後、
加熱濃縮して８１１重量部となる迄水分を蒸発させた
後、２５℃まで冷却して１時間保持し結晶を晶出させ
た。再度吸引濾過して４９２重量部の白色結晶を得た。
乾燥後の白色結晶の分析値を表２に示す。After filtering the filtrate with a filter paper having a pore size of 1 μm,
After concentrating by heating to evaporate the water content to 811 parts by weight, the mixture was cooled to 25 ° C. and kept for 1 hour to crystallize crystals. Suction filtration was performed again to obtain 492 parts by weight of white crystals.
Table 2 shows the analytical values of the dried white crystals.
【００２６】次に、この回収結晶に新たなＫＦ及びＫＣ
ｌを加えて希釈塩とし、Ｋ2 Ｔa Ｆ7 のＮａ還元を実施
した。還元方法は実施例１と同様である。原料の配合条
件と操業結果を表３に示す。Next, new KF and KC are added to the recovered crystals.
1 was added to give a diluted salt, and K 2 Ta F 7 was reduced with Na. The reduction method is the same as in Example 1. Table 3 shows the raw material compounding conditions and the operation results.
【００２７】比較例 ＫＦとＮａＦを主成分とする副生混合塩１０００重量部
に４０℃の水２０００重量部を加え、水温を４０℃に維
持しながら２２時間撹拌溶解した。溶液のpHは１２．２
であった。Comparative Example 2000 parts by weight of water at 40 ° C. was added to 1000 parts by weight of a by-produced mixed salt containing KF and NaF as main components, and dissolved by stirring for 22 hours while maintaining the water temperature at 40 ° C. The pH of the solution is 12.2
Met.
【００２８】この溶液を吸引濾過し、残渣３８３重量部
と濾液２６０８重量部を得た。濾液を孔径１μm の濾紙
で濾過した後、加熱濃縮して８２８重量部となるまで水
分を蒸発させ、２５℃まで冷却して結晶を晶出させた。
再度吸引濾過して５６８重量部の結晶を得た。This solution was suction filtered to obtain 383 parts by weight of the residue and 2608 parts by weight of the filtrate. The filtrate was filtered with a filter paper having a pore size of 1 μm, and then concentrated by heating to evaporate the water content to 828 parts by weight, and cooled to 25 ° C. to crystallize crystals.
It was suction filtered again to obtain 568 parts by weight of crystals.
【００２９】結晶の組成はＫＦ：９０．０％、ＮａＦ：
８．８％、水分：０．８％、Ｆｅ：４ppm 、Ｎｉ：２pp
m 、Ｃｒ：２ppm 、Ｓｉ：５ppm 、Ｃａ：１ppm 、Ｍ
ｇ：１ppm 、Ｂ：１ppm であった。この結晶はＮａＦが
多くしかも有害不純物であるＦｅ、Ｓｉが高く、コンデ
ンサ用Ｔａ粉末製造用の希釈塩としては使用できなかっ
た。The composition of crystals is KF: 90.0%, NaF:
8.8%, water content: 0.8%, Fe: 4ppm, Ni: 2pp
m, Cr: 2ppm, Si: 5ppm, Ca: 1ppm, M
g: 1 ppm and B: 1 ppm. This crystal was high in NaF and high in harmful impurities such as Fe and Si, and could not be used as a diluting salt for producing Ta powder for capacitors.
【００３０】[0030]
【発明の効果】本発明によればＫ2 Ｔa Ｆ7 のＮａ還元
の際に副生する不純物を含んだ副生混合塩から、希釈塩
として有効なＫＦ、ＫＣｌ成分を高純度状態で回収でき
る。回収された塩はコンデンサ用Ｔａ粉末製造用の希釈
塩として利用できるものである。本発明により希釈塩を
リサイクルして使用できるようになるため、希釈塩のコ
ストが大幅に節減できるばかりでなく、副生物の処理費
用も大幅に削減できる効果を有する。INDUSTRIAL APPLICABILITY According to the present invention, KF and KCl components effective as diluent salts are recovered in a high purity state from a by-product mixed salt containing impurities by-produced during Na reduction of K 2 T a F 7. it can. The recovered salt can be used as a diluted salt for producing Ta powder for capacitors. Since the diluted salt can be recycled and used according to the present invention, not only the cost of the diluted salt can be significantly reduced, but also the cost of treating the by-product can be significantly reduced.
Claims (8)
合物を、フッ化カリウムを溶解するのに必要とする量ま
たはそれ以下の水に溶解して濾過し、残渣としてフッ化
ナトリウムを回収すると同時に、濾液を加熱濃縮して冷
却し、フッ化カリウムを晶出させることを特徴とするフ
ッ化カリウムの分離精製方法。1. A mixture of potassium fluoride and sodium fluoride is dissolved in water in an amount or less required to dissolve potassium fluoride and filtered to collect sodium fluoride as a residue, and at the same time, A method for separating and purifying potassium fluoride, which comprises concentrating and cooling the filtrate by heating to crystallize potassium fluoride.
塩化カリウムの混合物を、フッ化カリウムと塩化カリウ
ムが溶解するのに必要とする量またはそれ以下の水に溶
解して濾過し、残渣としてフッ化ナトリウムを回収する
と同時に、濾液を加熱濃縮して冷却し、フッ化カリウム
及び塩化カリウムを晶出させることを特徴とするフッ化
カリウムの分離精製方法。2. A mixture of potassium fluoride, sodium fluoride and potassium chloride is dissolved in water in an amount necessary for dissolving potassium fluoride and potassium chloride or less, and the mixture is filtered to obtain a fluoride residue. A method for separating and purifying potassium fluoride, which comprises recovering sodium and, at the same time, concentrating and cooling the filtrate by heating to crystallize potassium fluoride and potassium chloride.
還元して得られる副生混合塩を、混合塩中のフッ化カリ
ウムが溶解するのに必要とする量またはそれ以下の水に
溶解して濾過し、濾液を加熱濃縮して冷却後に晶出する
フッ化カリウムを、再びフッ化タンタルカリウム還元工
程の希釈塩として使用することを特徴とするタンタルの
還元方法。3. A by-product mixed salt obtained by reducing potassium tantalum fluoride with an alkali metal is dissolved in water in an amount or less required for dissolving potassium fluoride in the mixed salt and filtered. A method for reducing tantalum, characterized in that potassium fluoride crystallized after heating and condensing the filtrate is used again as a diluting salt in the tantalum potassium fluoride reduction step.
還元して得られる副生混合塩を、混合塩中のフッ化カリ
ウム及び塩化カリウムが溶解するのに必要とする量また
はそれ以下の水に溶解して濾過し、濾液を加熱濃縮して
冷却後に晶出するフッ化カリウム及び塩化カリウムを、
再びフッ化タンタルカリウム還元工程の希釈塩として使
用することを特徴とするタンタルの還元方法。4. The by-product mixed salt obtained by reducing potassium tantalum fluoride with an alkali metal is dissolved in water in an amount or less required for dissolving potassium fluoride and potassium chloride in the mixed salt. Filtered, the filtrate is heated and concentrated, and potassium fluoride and potassium chloride that crystallize after cooling,
A method for reducing tantalum, which is used again as a diluting salt in a potassium tantalum fluoride reduction step.
量が、フッ化タンタルカリウム原料の０．２〜２．５倍
（重量比）であることを特徴とする請求項３記載のタン
タルの還元方法。5. The reduction of tantalum according to claim 3, wherein the amount of potassium fluoride used as a diluting salt is 0.2 to 2.5 times (weight ratio) of the tantalum potassium fluoride raw material. Method.
量が、フッ化タンタルカリウム原料の０．２〜２．５倍
（重量比）であり、塩化カリウムの量がフッ化タンタル
カリウム原料の３．０倍以下（重量比）であることを特
徴とする請求項４記載のタンタルの還元方法。6. The amount of potassium fluoride used as the diluting salt is 0.2 to 2.5 times (weight ratio) that of the tantalum potassium fluoride raw material, and the amount of potassium chloride is 3 times that of the tantalum potassium fluoride raw material. 5. The method for reducing tantalum according to claim 4, wherein the reduction ratio is 0.0 times or less (weight ratio).
なうことを特徴とする請求項３ないし請求項６記載のタ
ンタルの還元方法。7. The method for reducing tantalum according to claim 3, wherein the by-product mixed salt is dissolved at 25 to 40 ° C.
カリ性水中でおこなうことを特徴とする請求項３ないし
請求項７記載のタンタルの還元方法。8. The method for reducing tantalum according to claim 3, wherein the mixed salt by-product is dissolved in alkaline water having a pH of 12 to 14.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP4063590A JP2547500B2 (en) | 1992-03-19 | 1992-03-19 | How to reduce tantalum |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP4063590A JP2547500B2 (en) | 1992-03-19 | 1992-03-19 | How to reduce tantalum |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH06322402A true JPH06322402A (en) | 1994-11-22 |
| JP2547500B2 JP2547500B2 (en) | 1996-10-23 |
Family
ID=13233639
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP4063590A Expired - Fee Related JP2547500B2 (en) | 1992-03-19 | 1992-03-19 | How to reduce tantalum |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP2547500B2 (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US8906117B2 (en) | 2009-10-20 | 2014-12-09 | Solvay Sa | Process for the combined regeneration of soluble salts contained in a residue of an industrial process |
| CN112441600A (en) * | 2019-08-30 | 2021-03-05 | 联化科技(盐城)有限公司 | Separation method of industrial mixed potassium salt |
| CN115353123A (en) * | 2022-08-16 | 2022-11-18 | 珠海正杏新材料科技有限公司 | Method for recovering potassium fluoride |
Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5333995A (en) * | 1976-09-11 | 1978-03-30 | Morita Kagaku Kogyo | Separating process for potassium fluoride and potassium chloride |
| JPH0248413A (en) * | 1988-08-05 | 1990-02-19 | Showa Denko Kk | Production of anhydrous potassium fluoride powder |
-
1992
- 1992-03-19 JP JP4063590A patent/JP2547500B2/en not_active Expired - Fee Related
Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5333995A (en) * | 1976-09-11 | 1978-03-30 | Morita Kagaku Kogyo | Separating process for potassium fluoride and potassium chloride |
| JPH0248413A (en) * | 1988-08-05 | 1990-02-19 | Showa Denko Kk | Production of anhydrous potassium fluoride powder |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US8906117B2 (en) | 2009-10-20 | 2014-12-09 | Solvay Sa | Process for the combined regeneration of soluble salts contained in a residue of an industrial process |
| CN112441600A (en) * | 2019-08-30 | 2021-03-05 | 联化科技(盐城)有限公司 | Separation method of industrial mixed potassium salt |
| CN115353123A (en) * | 2022-08-16 | 2022-11-18 | 珠海正杏新材料科技有限公司 | Method for recovering potassium fluoride |
| CN115353123B (en) * | 2022-08-16 | 2023-12-05 | 珠海正杏新材料科技有限公司 | Recovery method of potassium fluoride |
Also Published As
| Publication number | Publication date |
|---|---|
| JP2547500B2 (en) | 1996-10-23 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| RU2233898C2 (en) | Method of preparation of magnesium chloride solution | |
| CA1188483A (en) | Process of producing potassium tetrafluoro aluminate | |
| US5635146A (en) | Method for the dissolution and purification of tantalum pentoxide | |
| SK285016B6 (en) | Process for production of caesium salt | |
| US6383459B1 (en) | Method for purifying a tantalum compound using a fluoride compound and sulfuric acid | |
| US4457903A (en) | Semicontinuous process for the production of pure silicon | |
| JPH0517832A (en) | Method for recovering lithium from waste lithium batteries | |
| US2808313A (en) | Method for the production of high purity caesium compounds from caesium-bearing minerals | |
| US6764669B2 (en) | Method for producing fluorinated potassium tantalate crystal | |
| JP4174708B2 (en) | Method for recovering and purifying calcium fluoride from a by-product mixed salt containing fluorine | |
| EP1264799A1 (en) | Process for the purification of aqueous metal salt solutions | |
| JP5421088B2 (en) | Method for producing valuable materials and hydrochloric acid from waste liquid | |
| JP2547500B2 (en) | How to reduce tantalum | |
| KR20070095439A (en) | How to prepare cesium hydroxide solution | |
| JP4275939B2 (en) | Method for recovering tantalum compound and / or niobium compound | |
| JP3382561B2 (en) | High purity phosphoric acid | |
| JP4322122B2 (en) | Method for purifying high-purity niobium compound and / or tantalum compound | |
| JP4351912B2 (en) | Method for purifying niobium compound and / or tantalum compound | |
| JPH01313333A (en) | Production of niobium hydroxide or tantalum hydroxide having high purity | |
| JP4322008B2 (en) | Method for recovering tantalum compound and / or niobium compound | |
| US1261948A (en) | Process of purifying zirconium ores. | |
| US5019158A (en) | Process for the separation of calcium and nitrogen from lithium | |
| JP2004521060A (en) | Method for removing sodium sulfate from nickel hydroxide waste stream | |
| JP4360452B2 (en) | Complete recycling of by-products in tantalum production | |
| JP3137226B2 (en) | Production method of high purity strontium chloride |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| R250 | Receipt of annual fees |
Free format text: JAPANESE INTERMEDIATE CODE: R250 |
|
| LAPS | Cancellation because of no payment of annual fees |