FR2263977A1 - Purifn of sodium hydroxide solns - by cooling to supersaln, pptg crystals, classifying and removing impure crystals with classifying soln - Google Patents
Purifn of sodium hydroxide solns - by cooling to supersaln, pptg crystals, classifying and removing impure crystals with classifying solnInfo
- Publication number
- FR2263977A1 FR2263977A1 FR7408204A FR7408204A FR2263977A1 FR 2263977 A1 FR2263977 A1 FR 2263977A1 FR 7408204 A FR7408204 A FR 7408204A FR 7408204 A FR7408204 A FR 7408204A FR 2263977 A1 FR2263977 A1 FR 2263977A1
- Authority
- FR
- France
- Prior art keywords
- classifying
- soln
- crystals
- cooling
- supersaln
- 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.)
- Withdrawn
Links
- HEMHJVSKTPXQMS-UHFFFAOYSA-M Sodium hydroxide Chemical compound [OH-].[Na+] HEMHJVSKTPXQMS-UHFFFAOYSA-M 0.000 title abstract 18
- 239000013078 crystal Substances 0.000 title abstract 8
- 238000001816 cooling Methods 0.000 title abstract 2
- 239000012535 impurity Substances 0.000 abstract 4
- FAPWRFPIFSIZLT-UHFFFAOYSA-M Sodium chloride Chemical compound [Na+].[Cl-] FAPWRFPIFSIZLT-UHFFFAOYSA-M 0.000 abstract 2
- 238000000034 method Methods 0.000 abstract 1
- 238000004064 recycling Methods 0.000 abstract 1
- 239000002002 slurry Substances 0.000 abstract 1
- 239000011780 sodium chloride Substances 0.000 abstract 1
- 238000005406 washing Methods 0.000 abstract 1
Classifications
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01D—COMPOUNDS OF ALKALI METALS, i.e. LITHIUM, SODIUM, POTASSIUM, RUBIDIUM, CAESIUM, OR FRANCIUM
- C01D1/00—Oxides or hydroxides of sodium, potassium or alkali metals in general
- C01D1/04—Hydroxides
- C01D1/28—Purification; Separation
- C01D1/30—Purification; Separation by crystallisation
Landscapes
- Chemical & Material Sciences (AREA)
- Organic Chemistry (AREA)
- Engineering & Computer Science (AREA)
- Materials Engineering (AREA)
- Inorganic Chemistry (AREA)
- Extraction Or Liquid Replacement (AREA)
Abstract
Method esp. for reducing diaphragm cell effluent impurities (partic NaCl) to 0.01-0.001 %, involves (a) cooling soln to NaOH hydrate supersatn. temp. (b) forming from this soln a slurry of large NaOH hydrate crystals and finer impurity crystals (e) separating the two by countercurrent contact with a classifying soln such that the fine impurity crystals are carried with the classifying soln and the larger NaOH hydrate crystals settle to form a bed (d) separating the classifying soln. (e) removing the fine impurity crystals from the classifying soln (f) adding NaOH soln to the classifying soln and recycling to step (a), and (g) removing and washing the NaOH hydrate crystals.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| FR7408204A FR2263977A1 (en) | 1974-03-11 | 1974-03-11 | Purifn of sodium hydroxide solns - by cooling to supersaln, pptg crystals, classifying and removing impure crystals with classifying soln |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| FR7408204A FR2263977A1 (en) | 1974-03-11 | 1974-03-11 | Purifn of sodium hydroxide solns - by cooling to supersaln, pptg crystals, classifying and removing impure crystals with classifying soln |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| FR2263977A1 true FR2263977A1 (en) | 1975-10-10 |
Family
ID=9136122
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| FR7408204A Withdrawn FR2263977A1 (en) | 1974-03-11 | 1974-03-11 | Purifn of sodium hydroxide solns - by cooling to supersaln, pptg crystals, classifying and removing impure crystals with classifying soln |
Country Status (1)
| Country | Link |
|---|---|
| FR (1) | FR2263977A1 (en) |
-
1974
- 1974-03-11 FR FR7408204A patent/FR2263977A1/en not_active Withdrawn
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| ST | Notification of lapse |