NO312505B1 - Process for purifying an aqueous solution of alkali metal chloride to remove iodine - Google Patents
Process for purifying an aqueous solution of alkali metal chloride to remove iodine Download PDFInfo
- Publication number
- NO312505B1 NO312505B1 NO19932247A NO932247A NO312505B1 NO 312505 B1 NO312505 B1 NO 312505B1 NO 19932247 A NO19932247 A NO 19932247A NO 932247 A NO932247 A NO 932247A NO 312505 B1 NO312505 B1 NO 312505B1
- Authority
- NO
- Norway
- Prior art keywords
- iodine
- activated carbon
- solution
- alkali metal
- purifying
- Prior art date
Links
- 229910052740 iodine Inorganic materials 0.000 title claims abstract description 60
- 239000011630 iodine Substances 0.000 title claims abstract description 60
- 238000000034 method Methods 0.000 title claims abstract description 21
- 229910001514 alkali metal chloride Inorganic materials 0.000 title claims abstract description 9
- ZCYVEMRRCGMTRW-UHFFFAOYSA-N 7553-56-2 Chemical compound [I] ZCYVEMRRCGMTRW-UHFFFAOYSA-N 0.000 title claims abstract 7
- 239000007864 aqueous solution Substances 0.000 title claims description 11
- PNDPGZBMCMUPRI-UHFFFAOYSA-N iodine Chemical compound II PNDPGZBMCMUPRI-UHFFFAOYSA-N 0.000 claims abstract description 70
- 230000003647 oxidation Effects 0.000 claims abstract description 16
- 238000007254 oxidation reaction Methods 0.000 claims abstract description 16
- ZAMOUSCENKQFHK-UHFFFAOYSA-N Chlorine atom Chemical compound [Cl] ZAMOUSCENKQFHK-UHFFFAOYSA-N 0.000 claims abstract description 9
- 239000000460 chlorine Substances 0.000 claims abstract description 9
- 229910052801 chlorine Inorganic materials 0.000 claims abstract description 9
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 claims description 89
- 239000000243 solution Substances 0.000 claims description 21
- XMBWDFGMSWQBCA-UHFFFAOYSA-N hydrogen iodide Chemical compound I XMBWDFGMSWQBCA-UHFFFAOYSA-N 0.000 claims description 7
- 230000002378 acidificating effect Effects 0.000 claims description 4
- 239000003638 chemical reducing agent Substances 0.000 claims description 4
- 239000011734 sodium Substances 0.000 claims description 4
- 239000002904 solvent Substances 0.000 claims description 3
- 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 2
- 229910052783 alkali metal Inorganic materials 0.000 claims description 2
- 150000002496 iodine Chemical class 0.000 claims description 2
- 150000001340 alkali metals Chemical class 0.000 claims 1
- 229910052708 sodium Inorganic materials 0.000 claims 1
- FAPWRFPIFSIZLT-UHFFFAOYSA-M Sodium chloride Chemical compound [Na+].[Cl-] FAPWRFPIFSIZLT-UHFFFAOYSA-M 0.000 abstract description 32
- 239000011780 sodium chloride Substances 0.000 abstract description 13
- 239000012528 membrane Substances 0.000 abstract description 5
- 230000001590 oxidative effect Effects 0.000 abstract description 2
- 239000003610 charcoal Substances 0.000 abstract 2
- 238000000746 purification Methods 0.000 abstract 1
- 239000012266 salt solution Substances 0.000 description 29
- 239000011347 resin Substances 0.000 description 11
- 229920005989 resin Polymers 0.000 description 11
- 229910052799 carbon Inorganic materials 0.000 description 10
- 238000001179 sorption measurement Methods 0.000 description 9
- 230000002829 reductive effect Effects 0.000 description 7
- CDBYLPFSWZWCQE-UHFFFAOYSA-L Sodium Carbonate Chemical compound [Na+].[Na+].[O-]C([O-])=O CDBYLPFSWZWCQE-UHFFFAOYSA-L 0.000 description 4
- 238000005868 electrolysis reaction Methods 0.000 description 4
- 238000010828 elution Methods 0.000 description 4
- KHIWWQKSHDUIBK-UHFFFAOYSA-N periodic acid Chemical compound OI(=O)(=O)=O KHIWWQKSHDUIBK-UHFFFAOYSA-N 0.000 description 4
- LSNNMFCWUKXFEE-UHFFFAOYSA-L sulfite Chemical compound [O-]S([O-])=O LSNNMFCWUKXFEE-UHFFFAOYSA-L 0.000 description 4
- -1 ammonium ions Chemical class 0.000 description 3
- 125000000129 anionic group Chemical group 0.000 description 3
- 239000002245 particle Substances 0.000 description 3
- MYRTYDVEIRVNKP-UHFFFAOYSA-N 1,2-Divinylbenzene Chemical compound C=CC1=CC=CC=C1C=C MYRTYDVEIRVNKP-UHFFFAOYSA-N 0.000 description 2
- WECIKJKLCDCIMY-UHFFFAOYSA-N 2-chloro-n-(2-cyanoethyl)acetamide Chemical compound ClCC(=O)NCCC#N WECIKJKLCDCIMY-UHFFFAOYSA-N 0.000 description 2
- OYPRJOBELJOOCE-UHFFFAOYSA-N Calcium Chemical compound [Ca] OYPRJOBELJOOCE-UHFFFAOYSA-N 0.000 description 2
- VEXZGXHMUGYJMC-UHFFFAOYSA-N Hydrochloric acid Chemical compound Cl VEXZGXHMUGYJMC-UHFFFAOYSA-N 0.000 description 2
- MHAJPDPJQMAIIY-UHFFFAOYSA-N Hydrogen peroxide Chemical compound OO MHAJPDPJQMAIIY-UHFFFAOYSA-N 0.000 description 2
- FYYHWMGAXLPEAU-UHFFFAOYSA-N Magnesium Chemical compound [Mg] FYYHWMGAXLPEAU-UHFFFAOYSA-N 0.000 description 2
- WCUXLLCKKVVCTQ-UHFFFAOYSA-M Potassium chloride Chemical compound [Cl-].[K+] WCUXLLCKKVVCTQ-UHFFFAOYSA-M 0.000 description 2
- PPBRXRYQALVLMV-UHFFFAOYSA-N Styrene Chemical compound C=CC1=CC=CC=C1 PPBRXRYQALVLMV-UHFFFAOYSA-N 0.000 description 2
- 238000010521 absorption reaction Methods 0.000 description 2
- 239000011575 calcium Substances 0.000 description 2
- 229910052791 calcium Inorganic materials 0.000 description 2
- 210000004534 cecum Anatomy 0.000 description 2
- 238000011049 filling Methods 0.000 description 2
- 239000010419 fine particle Substances 0.000 description 2
- WQYVRQLZKVEZGA-UHFFFAOYSA-N hypochlorite Chemical compound Cl[O-] WQYVRQLZKVEZGA-UHFFFAOYSA-N 0.000 description 2
- ICIWUVCWSCSTAQ-UHFFFAOYSA-M iodate Chemical compound [O-]I(=O)=O ICIWUVCWSCSTAQ-UHFFFAOYSA-M 0.000 description 2
- 239000011777 magnesium Substances 0.000 description 2
- 229910052749 magnesium Inorganic materials 0.000 description 2
- 239000007800 oxidant agent Substances 0.000 description 2
- 239000002244 precipitate Substances 0.000 description 2
- 230000008929 regeneration Effects 0.000 description 2
- 238000011069 regeneration method Methods 0.000 description 2
- 235000017550 sodium carbonate Nutrition 0.000 description 2
- 229910000029 sodium carbonate Inorganic materials 0.000 description 2
- 150000003467 sulfuric acid derivatives Chemical class 0.000 description 2
- NWUYHJFMYQTDRP-UHFFFAOYSA-N 1,2-bis(ethenyl)benzene;1-ethenyl-2-ethylbenzene;styrene Chemical compound C=CC1=CC=CC=C1.CCC1=CC=CC=C1C=C.C=CC1=CC=CC=C1C=C NWUYHJFMYQTDRP-UHFFFAOYSA-N 0.000 description 1
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 1
- VEXZGXHMUGYJMC-UHFFFAOYSA-M Chloride anion Chemical compound [Cl-] VEXZGXHMUGYJMC-UHFFFAOYSA-M 0.000 description 1
- 235000013162 Cocos nucifera Nutrition 0.000 description 1
- 244000060011 Cocos nucifera Species 0.000 description 1
- 239000003929 acidic solution Substances 0.000 description 1
- 239000012736 aqueous medium Substances 0.000 description 1
- 229910052788 barium Inorganic materials 0.000 description 1
- DSAJWYNOEDNPEQ-UHFFFAOYSA-N barium atom Chemical compound [Ba] DSAJWYNOEDNPEQ-UHFFFAOYSA-N 0.000 description 1
- SSTZWBSEDRHYPU-UHFFFAOYSA-L barium(2+);diperiodate Chemical compound [Ba+2].[O-]I(=O)(=O)=O.[O-]I(=O)(=O)=O SSTZWBSEDRHYPU-UHFFFAOYSA-L 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- 150000004649 carbonic acid derivatives Chemical class 0.000 description 1
- 230000015556 catabolic process Effects 0.000 description 1
- 125000002091 cationic group Chemical group 0.000 description 1
- 238000006243 chemical reaction Methods 0.000 description 1
- 239000003795 chemical substances by application Substances 0.000 description 1
- 238000004140 cleaning Methods 0.000 description 1
- 229920001577 copolymer Polymers 0.000 description 1
- 238000006731 degradation reaction Methods 0.000 description 1
- 238000003795 desorption Methods 0.000 description 1
- 238000000605 extraction Methods 0.000 description 1
- 239000012535 impurity Substances 0.000 description 1
- 150000004694 iodide salts Chemical class 0.000 description 1
- 239000003456 ion exchange resin Substances 0.000 description 1
- 229920003303 ion-exchange polymer Polymers 0.000 description 1
- 239000002609 medium Substances 0.000 description 1
- 230000007935 neutral effect Effects 0.000 description 1
- VLTRZXGMWDSKGL-UHFFFAOYSA-N perchloric acid Chemical class OCl(=O)(=O)=O VLTRZXGMWDSKGL-UHFFFAOYSA-N 0.000 description 1
- 239000001103 potassium chloride Substances 0.000 description 1
- 235000011164 potassium chloride Nutrition 0.000 description 1
- 238000001556 precipitation Methods 0.000 description 1
- 125000001453 quaternary ammonium group Chemical group 0.000 description 1
- SUKJFIGYRHOWBL-UHFFFAOYSA-N sodium hypochlorite Chemical compound [Na+].Cl[O-] SUKJFIGYRHOWBL-UHFFFAOYSA-N 0.000 description 1
- 238000005406 washing Methods 0.000 description 1
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 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
- C01D3/14—Purification
- C01D3/16—Purification by precipitation or adsorption
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
- B01J20/00—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof
- B01J20/02—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof comprising inorganic material
- B01J20/20—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof comprising inorganic material comprising free carbon; comprising carbon obtained by carbonising processes
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
- B01J20/00—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof
- B01J20/30—Processes for preparing, regenerating, or reactivating
- B01J20/34—Regenerating or reactivating
- B01J20/3416—Regenerating or reactivating of sorbents or filter aids comprising free carbon, e.g. activated carbon
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
- C01B7/00—Halogens; Halogen acids
- C01B7/13—Iodine; Hydrogen iodide
- C01B7/14—Iodine
Landscapes
- Chemical & Material Sciences (AREA)
- Organic Chemistry (AREA)
- Inorganic Chemistry (AREA)
- Engineering & Computer Science (AREA)
- Materials Engineering (AREA)
- Water Treatment By Sorption (AREA)
- Treatment Of Water By Oxidation Or Reduction (AREA)
- Solid-Sorbent Or Filter-Aiding Compositions (AREA)
- Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
- Removal Of Specific Substances (AREA)
- Detergent Compositions (AREA)
- Cleaning And De-Greasing Of Metallic Materials By Chemical Methods (AREA)
- Electrolytic Production Of Non-Metals, Compounds, Apparatuses Therefor (AREA)
- Treating Waste Gases (AREA)
- Pharmaceuticals Containing Other Organic And Inorganic Compounds (AREA)
- Fats And Perfumes (AREA)
- Developing Agents For Electrophotography (AREA)
- Water Treatment By Electricity Or Magnetism (AREA)
Abstract
Description
Foreliggende oppfinnelse angår en fremgangsmåte for rensing av en vandig oppløsning av alkalimetallklorid for å fjerne jod. The present invention relates to a method for purifying an aqueous solution of alkali metal chloride to remove iodine.
Vandige oppløsninger av natriumklorid elektrolyseres for å fremstille klor og soda. Aqueous solutions of sodium chloride are electrolysed to produce chlorine and soda ash.
Når elektrolysen gjennomføres ved den såkalte "membran"-prosess, må den vandige oppløsning omhyggelig renses for å fjerne de vanlige urenheter i natriumkloridet som kalsium, magnesium og sulfater. Man benytter for eksempel precipitering med natriumkarbonat og etterfølgende absorpsjon på harpikser; slike prosesser er beskrevet i UllmamVs "Encyclopedia of Industrial Chemistry", bind A6-1986, side 448. Avhengig av opprinnelse kan natriumkloridoppløsningen også inneholde jod i form av jodid, I". When the electrolysis is carried out by the so-called "membrane" process, the aqueous solution must be carefully purified to remove the usual impurities in the sodium chloride such as calcium, magnesium and sulphates. One uses, for example, precipitation with sodium carbonate and subsequent absorption on resins; such processes are described in UllmamV's "Encyclopedia of Industrial Chemistry", volume A6-1986, page 448. Depending on its origin, the sodium chloride solution may also contain iodine in the form of iodide, I".
Publikasjonen "Research Disclosure nr. 30732" fra november 1989 forklarer at det jod som er tilstede i vandige natriumkloridoppløsninger i jodidform, oksyderes til perjodat i cellen under elektrolysen, dette perjodat precipiterer så i membranet og skader det. I henhold til denne publikasjon blir barium satt til oppløsningen før elektrolysen; det dannes så et meget fint og meget uoppløselig precipitat av bariumperjodat. The publication "Research Disclosure No. 30732" from November 1989 explains that the iodine present in aqueous sodium chloride solutions in iodide form is oxidized to periodate in the cell during electrolysis, this periodate then precipitates in the membrane and damages it. According to this publication, barium is added to the solution before the electrolysis; a very fine and very insoluble precipitate of barium periodate is then formed.
US-4.483.754 forklarer også at nærværet av jod i en vandig natriumkloirdoppløsning i en membranprosess resulterer i en hurtig nedbrytning av membranene. I henhold til denne kjente teknikk blir det jod som er tilstede i den vandige oppløsning i jodidform, oksydasjonstilstand -1, oksydert til molekylært jod, oksydasjonstilstand 0, og dette molekylære jod blir så fjernet fra den vandige kloridoppløsning enten ved absorpsjon på en anionisk harpiks eller ved stripping med luft i en kolonne. US-4,483,754 also explains that the presence of iodine in an aqueous sodium chloride solution in a membrane process results in a rapid degradation of the membranes. According to this known technique, the iodine present in the aqueous solution in iodide form, oxidation state -1, is oxidized to molecular iodine, oxidation state 0, and this molecular iodine is then removed from the aqueous chloride solution either by absorption on an anionic resin or by stripping with air in a column.
Eksempel 1 viser at en saltoppløsning inneholdende 80 ppm jod i Nal-form (95 ppm Nal) oksyderes og så føres over en anionisk harpiks med en romhastighet på 2 h~<l>, det vil si en saltoppløsningsstrøm per time på to ganger volumet av harpikssjiktet. Jodinnholdet i saltoppløsningen reduseres til 0,8 ppm. Example 1 shows that a salt solution containing 80 ppm iodine in Nal form (95 ppm Nal) is oxidized and then passed over an anionic resin with a space velocity of 2 h~<l>, i.e. a salt solution flow per hour of twice the volume of the resin layer. The iodine content in the salt solution is reduced to 0.8 ppm.
Eksempel 3 viser at jodinnholdet i en saltoppløsning kan reduseres fra 12 til 0,7 ppm ved stripping med luft. I henhold til dette patent og for å fjerne jod, er det mulig å benytte enten adsorpsjon på aktivkarbon eller på harpiks eller stripping med luft, idet det er mulig at disse tre midler kan benyttes hver for seg eller i kombinasjon. Example 3 shows that the iodine content in a salt solution can be reduced from 12 to 0.7 ppm by stripping with air. According to this patent and to remove iodine, it is possible to use either adsorption on activated carbon or on resin or stripping with air, as it is possible that these three agents can be used separately or in combination.
EP-søknad 399.588 beskriver en fremgangsmåte for rensing av en vandig natriumklorid-oppløsning, hvori jodidene oksyderes til molekylært jod som så adsorberes på en ione-bytteharpiks og derefter, i et etterfølgende trinn, ammoniumioner oksyderes til molekylært nitrogen som fjernes fra oppløsningen ved stripping med luft. EP application 399,588 describes a process for purifying an aqueous sodium chloride solution in which the iodides are oxidized to molecular iodine which is then adsorbed on an ion exchange resin and then, in a subsequent step, ammonium ions are oxidized to molecular nitrogen which is removed from the solution by stripping with air.
Harpiksen er av den anioniske type som har bundet kationiske seter som er kvaternære ammoniumgrupper bundet til langkjede-kopolymerer av styren eller divinylbenzen. Jodinnholdet i saltoppløsningen kan på denne måte reduseres fra 2,9 til 0,5 ppm i henhold til eksempel 1, fra 2,5 til 0,2 ppm i henhold til eksempel 2 eller fra 2,9 til 0,3 ppm i henhold til eksempel 3. The resin is of the anionic type which has bound cationic sites which are quaternary ammonium groups bound to long-chain copolymers of styrene or divinylbenzene. The iodine content in the salt solution can in this way be reduced from 2.9 to 0.5 ppm according to example 1, from 2.5 to 0.2 ppm according to example 2 or from 2.9 to 0.3 ppm according to example 3.
Et harpikssjikt kan ikke redusere jodinnholdet i saltoppløsningen til under 0,2 ppm. Volumet av harpiks er meget stort og strømningshastigheten per time av saltoppløsning er mellom 2 og 10 ganger volumet av harpiksen. Jodoppfyllingsforholdet for harpiksen er lavt på tidspunktet for jodlekkasjen, 0,5 ppm. Det er nå funnet at for å redusere jodinnholdet i en saltoppløsning fra 1,5 til 0,2 ppm, når jodlekkingen 0,5 ppm i det øyeblikk volumet av en saltoppløsning lik 250 ganger volumet av sjiktet er behandlet. A resin layer cannot reduce the iodine content of the salt solution below 0.2 ppm. The volume of resin is very large and the flow rate per hour of saline solution is between 2 and 10 times the volume of the resin. The iodine replenishment ratio of the resin is low at the time of the iodine leakage, 0.5 ppm. It has now been found that to reduce the iodine content of a salt solution from 1.5 to 0.2 ppm, the iodine leakage reaches 0.5 ppm at the moment the volume of a salt solution equal to 250 times the volume of the bed is treated.
US-4.483.754, nevnt ovenfor, presenterer adsorpsjon på harpiks som ekvivalent med adsorpsjon på aktivt karbon. Det er nå imidlertid funnet av situasjonen er helt anner-ledes. US-4,483,754, mentioned above, presents adsorption on resin as equivalent to adsorption on activated carbon. However, it has now been found that the situation is completely different.
Et sjikt av aktivt karbon kan redusere jodinnholdet for en saltoppløsning til 0,05 ppm. Volumet av aktivt karbon er lavt, og strømningsmengden per time for saltoppløsningen kan gå opp i 30 til 50 ganger volumet av karbon. Kapasiteten for karbonet er høyt, og det er funnet at, for å redusere jodinnholdet i en saltoppløsning fra 2 til 0,05 ppm, har sjiktet av aktivt karbon en jodlekkasje på over 0,5 ppm så snart et volum saltoppløsning lik 9 til 10.000 ganger sjiktvolumet, er behandlet. Det aktive karbonet kan lett regenereres. A layer of activated carbon can reduce the iodine content of a salt solution to 0.05 ppm. The volume of activated carbon is low, and the flow rate per hour of the salt solution can reach 30 to 50 times the volume of carbon. The capacity of the carbon is high, and it has been found that, to reduce the iodine content of a salt solution from 2 to 0.05 ppm, the layer of activated carbon has an iodine leakage of more than 0.5 ppm as soon as a volume of salt solution equal to 9 to 10,000 times the layer volume, is processed. The active carbon can be easily regenerated.
I henhold til dette angår foreliggende oppfinnelse en fremgangsmåte for rensing av en vandig oppløsning av alkalimetallklorid inneholdende jod og denne fremgangsmåte karakteriseres ved at jodet oksyderes til molekylært jod og så adsorberes på et sjikt av på forhånd oksydert aktivkarbon. According to this, the present invention relates to a method for purifying an aqueous solution of alkali metal chloride containing iodine and this method is characterized by the iodine being oxidized to molecular iodine and then adsorbed on a layer of previously oxidized activated carbon.
Den vandige alkalimetallkloridoppløsning (eller saltoppløsning) kan for eksempel være en oppløsning av natrium- eller kaliumklorid; denne oppløsning kan også inneholde alkalimetallklorater, perklorater eller sulfater. I en vandig alkalimetallkloridoppløsning er jodet i de fleste tilfeller i form av jodid, I". The aqueous alkali metal chloride solution (or salt solution) can be, for example, a solution of sodium or potassium chloride; this solution may also contain alkali metal chlorates, perchlorates or sulfates. In an aqueous alkali metal chloride solution, the iodine is in most cases in the form of iodide, I".
Oksydasjonen av jod til molekylært jodid gjennomføres ved bruk av et oksydasjonsmiddel som aktivt klor eller hydrogenperoksyd. For å oksydere under anvendelse av aktivt klor, er det tilstrekkelig å injisere klor, klorvann eller en hypokloritt i saltopp-løsningen. Det er også mulig å oksydere ved bruk av jodat eller et perjodat. The oxidation of iodine to molecular iodide is carried out using an oxidizing agent such as active chlorine or hydrogen peroxide. To oxidize using active chlorine, it is sufficient to inject chlorine, chlorine water or a hypochlorite into the salt solution. It is also possible to oxidize using iodate or a periodate.
Aktivt klor foretrekkes på grunn av den høyere oksydasjonskraft. Tilsetningen av oksydasjonsmiddel kan enkelt kontrolleres ved å måle rekox-potensialet, rH, for det vandige medium, det vil si saltoppløsningen, som må ligge mellom 460 og 560 mV/SCE, målt ved 50°C, fortrinnsvis mellom 500 og 550 mV/SCE. Denne oksydasjon gjennomføres fordelaktig på en saltoppløsning ved en pH-verdi under 3 og fortrinnsvis mellom 2 og 1,5. Active chlorine is preferred because of its higher oxidizing power. The addition of oxidizing agent can be easily checked by measuring the recox potential, rH, of the aqueous medium, i.e. the salt solution, which must lie between 460 and 560 mV/SCE, measured at 50°C, preferably between 500 and 550 mV/SCE . This oxidation is advantageously carried out in a salt solution at a pH value below 3 and preferably between 2 and 1.5.
Det skulle ikke være nødvendig å si at hvis jod allerede foreligger i molekylær jodform, er det intet behov for å gjennomføre oksydasjonen. Hvis jodet foreligger i en oksydert form over molekylært jod, blir de redusert til molekylært jod ved hjelp av et reduksjonsmiddel. Saltoppløsningen er generelt tilgjengelig ved basisk eller nøytral pH-verdi, og det er da tilstrekkelig til å tilsette noe saltsyre. Hvis saltoppløsningen inneholder karbonater, resulterer en endring til sur pH-verdi i en dekarbonering og CO2 gasses ut før oksydasjonen av jod til molekylært jod. It should not be necessary to say that if iodine is already present in molecular iodine form, there is no need to carry out the oxidation. If the iodine is present in an oxidized form above molecular iodine, they are reduced to molecular iodine by means of a reducing agent. The salt solution is generally available at a basic or neutral pH value, and it is then sufficient to add some hydrochloric acid. If the salt solution contains carbonates, a change to an acidic pH value results in a decarbonation and CO2 is outgassed before the oxidation of iodine to molecular iodine.
En hvilken som helst type aktivt karbon kan benyttes, men det er enklest å benytte et granulært karbon i et stasjonært sjikt, for eksempel med en partikkelstørrelse på 0,4 til 1,7 mm, for å redusere saltoppløsningstrykktapene. Gode resultater oppnås med et aktivt karbon NC 35 fra CECA, partikkelstørrelsen for dette aktive karbon er 0,4 til 1,25 mm, og det er et kokosnøttkarbon. Any type of activated carbon can be used, but it is easiest to use a granular carbon in a stationary bed, for example with a particle size of 0.4 to 1.7 mm, to reduce salt solution pressure losses. Good results are obtained with an active carbon NC 35 from CECA, the particle size of this active carbon is 0.4 to 1.25 mm, and it is a coconut carbon.
Aktivkarbonet er lett reduktivt overfor elementært jod, for å oppnå en bedre effektivitet oksyderes overflaten av aktivkarbonet i en viss grad. Denne oksydasjonsbehandling kan gjennomføres med en klorert oppløsning inneholdende fra noen mg/l til noen g/l aktivt klor. Når det gjelder natriumkloridsaltoppløsninger, kan det benyttes en NaCl-salt-oppløsning ved lett sur pH-verdi, for eksempel den utmagrede og klorerte saltopp-løsning som forlater et elektrolyserom. The activated carbon is easily reductive towards elemental iodine, to achieve better efficiency the surface of the activated carbon is oxidized to a certain extent. This oxidation treatment can be carried out with a chlorinated solution containing from a few mg/l to a few g/l of active chlorine. In the case of sodium chloride salt solutions, a NaCl salt solution can be used at a slightly acidic pH value, for example the depleted and chlorinated salt solution that leaves an electrolysis room.
Denne oksydasjon av aktivt karbon kan skje før man gjennomfører adsorpsjonen av jod, det vil si efter regenereringen av aktivkarbonet. Det er ikke å gå utenfor oppfinnelsens ramme å gjennomføre denne oksydasjon under adsorpsjonen av jod under anvendelse av saltoppløsningen som skal renses med henblikk pa jod; det er tilstrekkelig a oksydere jodet partielt eller fullstendig over molekylært jod, det vil si til en oksydasjonstilstand over 0 (for eksempel jodat eller perjodat). Det er også mulig å kombinere en oksydasjon av jodet før adsorpsjonen og en oksydasjon under adsorpsjonen. This oxidation of activated carbon can take place before the adsorption of iodine is carried out, that is to say after the regeneration of the activated carbon. It is not beyond the scope of the invention to carry out this oxidation during the adsorption of iodine using the salt solution to be purified for iodine; it is sufficient to oxidize the iodine partially or completely above molecular iodine, that is to an oxidation state above 0 (for example iodate or periodate). It is also possible to combine an oxidation of the iodine before the adsorption and an oxidation during the adsorption.
Med et aktivkarbon som er oksydert før adsorpsjonen av jod, kan en saltoppløsning med 300 g/l NaCl og inneholdende opptil 10 mg/ljod, renses effektivt hvis pH-verdien holdes mellom 1,6 og 2 og hvis rH-verdien for mediet kontrolleres. With an activated carbon that is oxidized before the adsorption of iodine, a salt solution with 300 g/l NaCl and containing up to 10 mg/iodine can be effectively purified if the pH value is kept between 1.6 and 2 and if the rH value of the medium is controlled.
Jodinnholdet av 10.000 SV saltoppløsning er redusert fra 10 mg/l til mindre enn 0,05 mg/l. The iodine content of 10,000 SV saline solution has been reduced from 10 mg/l to less than 0.05 mg/l.
(SV : sjiktvolum, volumet av aktivkarbon-sjiktet). (SV : layer volume, the volume of the activated carbon layer).
Det er så tilstrekkelig å regenerere aktivkarbonet ved å fjerne jod med et oppløsnings-middel for jod eller et reduksjonsmiddel. It is then sufficient to regenerate the activated carbon by removing iodine with a solvent for iodine or a reducing agent.
Aktivkarbonsjiktet kan regenereres, for eksempel med en sulfittoppløsning. Det elementære jod reduseres med sulfittion i henhold til reaksjonen: The activated carbon layer can be regenerated, for example with a sulphite solution. The elemental iodine is reduced by the sulphite ion according to the reaction:
Jodet kan så ekstraheres fra aktivkarbonet som et resultat av fraværet av affinitet mellom jodid og aktivkarbon. The iodine can then be extracted from the activated carbon as a result of the absence of affinity between iodide and activated carbon.
Det er foretrukket å benytte en lett sur oppløsning for å unngå opptredenen av fine partikler av aktivkarbon under elueringen. Hvis elueringen gjennomføres med et basisk oppløsningsmiddel er det en risiko for at fine partikler av aktivkarbon kan finnes i eluatet. It is preferred to use a slightly acidic solution to avoid the appearance of fine particles of activated carbon during the elution. If the elution is carried out with a basic solvent, there is a risk that fine particles of activated carbon may be found in the eluate.
Sulfittoppløsningen har fortrinnsvis en pH-verdi på 3 til 5. Ved utløpet av kolonnen er det vanlig at pH-verdien synker til under 1 som et resultat av dannelsen av H+. The sulphite solution preferably has a pH value of 3 to 5. At the outlet of the column it is common for the pH value to drop below 1 as a result of the formation of H+.
Eluering med en sulfittoppløsning inneholdende 1 til 20 g/l Na2SC>4 gjør det mulig å ekstrahere praktisk talt alt jod som er absorbert av aktivkarbonet. Elution with a sulphite solution containing 1 to 20 g/l Na 2 SC> 4 makes it possible to extract practically all the iodine absorbed by the activated carbon.
Når jod så er ekstrahert fra aktivkarbonet, kan den sistnevnte underkastes oksydasjonsbehandling som beskrevet ovenfor, og benyttes igjen for rengjøring av saltoppløsning inneholdende jod. When iodine has then been extracted from the activated carbon, the latter can be subjected to oxidation treatment as described above, and used again for cleaning salt solution containing iodine.
Regenerering av aktivkarbon kan gjennomføres ved et antall vaskinger i en lukket sløyfe med en lett sur, vandig, sulfittoppløsning. Karbonet blir så skyllet med en vandig oppløsning med pH-verdi mellom 1 og 3, og denne mildt reduserende oppløsning tillater at de siste spor av jod fjernes. Regeneration of activated carbon can be carried out by a number of washings in a closed loop with a slightly acidic, aqueous, sulphite solution. The carbon is then rinsed with an aqueous solution of pH between 1 and 3, and this mildly reducing solution allows the last traces of iodine to be removed.
Fremgangsmåten ifølge oppfinnelsen anvendes fortrinnsvis på vandige oppløsninger som allerede er renset for kalsium og magnesium. The method according to the invention is preferably used on aqueous solutions that have already been purified from calcium and magnesium.
I en utførelsesform av oppfinnelsen angår den en fremgangsmåte for rensing av en vandig oppløsning av alkalimetallklorid inneholdende jod i form av molekylært jod og denne fremgangsmåte karakteriseres ved at dette jod absorberes på et sjikt av på forhånd oksydert aktivkarbon. In one embodiment of the invention, it relates to a method for purifying an aqueous solution of alkali metal chloride containing iodine in the form of molecular iodine and this method is characterized by the fact that this iodine is absorbed on a layer of previously oxidized activated carbon.
Det er her tilstrekkelig å gjennomføre operasjonen som ovenfor uten jodoksydasjons-trinnet. It is sufficient here to carry out the operation as above without the iodine oxidation step.
EKSEMPEL 1 ISammenligningseksempel] EXAMPLE 1 IComparison example]
50 g aktivkarbon med partikkelstørrelse 0,4-1,25 mm (CECA referanse NC35) anbringes i en kolonne. Saltoppløsningen med pH = 1,6, T = 50°C, rH = 500 - 530 mV/SCE ved 50°C, inneholder 2,2 mg/ljod. Det er en natriumkloirdoppløsning inneholdende 300 g/l NaCl. Strømningshastigheten er lik 45 SV/time, det vil si at strømningsmengden saltoppløsning pr. time 45 ganger volumet av aktivkarbon-sjiktet. 50 g of activated carbon with a particle size of 0.4-1.25 mm (CECA reference NC35) are placed in a column. The salt solution with pH = 1.6, T = 50°C, rH = 500 - 530 mV/SCE at 50°C, contains 2.2 mg/Iodine. It is a sodium chloride solution containing 300 g/l NaCl. The flow rate is equal to 45 SV/hour, that is, the flow amount of saline solution per hour 45 times the volume of the activated carbon layer.
Jodinnholdet i kolonneutløpet fluktuerer mellom 0,2 og 0,5 mg/l i 200 timer. The iodine content in the column outlet fluctuates between 0.2 and 0.5 mg/l for 200 hours.
EKSEMPEL 2 EXAMPLE 2
Prosedyren er som i eksempel 1, på den annen side er de 50 g aktivkarbon oksydert med 15 g NaCIO, operasjonen ble gjennomført med 10 SV/time for en saltoppløsning ved en konsentrasjon på 300 g/l NaCl inneholdende 200 mg/l NaCIO. The procedure is as in example 1, on the other hand, the 50 g of activated carbon are oxidized with 15 g of NaCIO, the operation was carried out at 10 SV/hour for a salt solution at a concentration of 300 g/l NaCl containing 200 mg/l NaCIO.
Jodinnholdet i kolonneutløpet forble under 0,05 mg/l i 200 timer. The iodine content of the column outlet remained below 0.05 mg/l for 200 hours.
EKSEMPEL 3 EXAMPLE 3
Aktivkarbonet fra eksempel 2 regenereres efter et forsøk på 100 timer adsorpsjon. Den beregnede oppfyllingsgrad er da 8% (det vil si 4 g jod). The activated carbon from example 2 is regenerated after a trial of 100 hours of adsorption. The calculated degree of filling is then 8% (that is, 4 g of iodine).
Ekstraheringen av jod fra karbonet gjennomføres med en Na2S03-oppløsning med pH-verdi lik 4 ved en konsentrasjon på 10 g/l ved føring gjennom kolonnen ved 3 SV/time i 2 1/2 time. Desorpsjonen følges av en skylling med en mildt reduserende saltoppløsning inneholdende * 200 g/l NaCl. The extraction of iodine from the carbon is carried out with a Na 2 SO 3 solution with a pH value equal to 4 at a concentration of 10 g/l by passing through the column at 3 SV/hour for 2 1/2 hours. The desorption is followed by a rinse with a mildly reducing salt solution containing * 200 g/l NaCl.
98,5% av det ventede jod (i henhold til det beregnede oppfyllingsforhold) ble ekstrahert fra aktivkarbonet. 98.5% of the expected iodine (according to the calculated filling ratio) was extracted from the activated carbon.
EKSEMPEL 4 EXAMPLE 4
En kolonne inneholdende 75 g aktivkarbon ble aktivert (med en 200 g/l saltoppløsning inneholdende 3 g/l NaCIO) som løp gjennom kolonnen i en strømningsmengde av 10 SV/time. Ekvivalenten til 25 g NaCIO ble benyttet for å oksydere de 75 g aktivkarbon. Saltoppløsningen er identisk med den i eksempel 1. På den annen side er strømnings-mengden 30 SV/time, og aktivkarbonet var oksydert. A column containing 75 g of activated carbon was activated (with a 200 g/l saline solution containing 3 g/l NaClO) running through the column at a flow rate of 10 SV/hr. The equivalent of 25 g of NaCIO was used to oxidize the 75 g of activated carbon. The salt solution is identical to that in example 1. On the other hand, the flow rate is 30 SV/hour, and the activated carbon was oxidized.
Jodinnholdet i kolonneutløpet forble under 0,05 mg/l i mer enn 300 timer. The iodine content of the column effluent remained below 0.05 mg/l for more than 300 hours.
EKSEMPEL 5 EXAMPLE 5
En aktivkarbon-kolonne på 45 g inneholdt« 25 vekt-% jod efter drift i 950 timer. Denne oppfylling ble oppnådd ved behandling av en saltoppløsning inneholdende 10 mg/ljod. An activated carbon column of 45 g contained 25% by weight of iodine after operation for 950 hours. This replenishment was achieved by treatment with a saline solution containing 10 mg/iod.
En oppløsning på 10 g/l Na2S03 med pH = 4 ble ført gjennom kolonnen i en mengde av 3 SV/time. Efter 8 timer var 10,95 g jod ekstrahert fra aktivkarbonet, det vil si mer enn 96% av det adsorberte jod. A solution of 10 g/l Na 2 SO 3 with pH = 4 was passed through the column at a rate of 3 SV/hour. After 8 hours, 10.95 g of iodine had been extracted from the activated carbon, that is, more than 96% of the adsorbed iodine.
Under elueringstrinnet hadde aktivkarbonet ikke undergått noen skade. During the elution step, the activated carbon had not undergone any damage.
Claims (7)
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| FR9207914A FR2692879B1 (en) | 1992-06-26 | 1992-06-26 | Process for the purification of an aqueous solution of alkali metal chloride to remove iodine. |
Publications (3)
| Publication Number | Publication Date |
|---|---|
| NO932247D0 NO932247D0 (en) | 1993-06-17 |
| NO932247L NO932247L (en) | 1993-12-30 |
| NO312505B1 true NO312505B1 (en) | 2002-05-21 |
Family
ID=9431265
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| NO19932247A NO312505B1 (en) | 1992-06-26 | 1993-06-17 | Process for purifying an aqueous solution of alkali metal chloride to remove iodine |
Country Status (13)
| Country | Link |
|---|---|
| EP (1) | EP0576335B1 (en) |
| JP (1) | JPH0791666B2 (en) |
| KR (1) | KR100237429B1 (en) |
| CN (1) | CN1040738C (en) |
| AT (1) | ATE135331T1 (en) |
| CA (1) | CA2099184C (en) |
| DE (1) | DE69301778T2 (en) |
| DK (1) | DK0576335T3 (en) |
| ES (1) | ES2087678T3 (en) |
| FI (1) | FI932936A (en) |
| FR (1) | FR2692879B1 (en) |
| GR (1) | GR3020029T3 (en) |
| NO (1) | NO312505B1 (en) |
Families Citing this family (15)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101171202B (en) * | 2005-05-02 | 2010-12-08 | 日宝化学株式会社 | Process for the recovery of iodine |
| US10013381B2 (en) | 2006-08-31 | 2018-07-03 | Bose Corporation | Media playing from a docked handheld media device |
| KR101046433B1 (en) | 2008-09-10 | 2011-07-05 | 한국화학연구원 | How to remove iodine mixture from aqueous solution |
| JP5571416B2 (en) | 2010-03-17 | 2014-08-13 | Ｊｘ日鉱日石金属株式会社 | Copper sulfide ore leaching method |
| AU2011255908B2 (en) | 2010-05-19 | 2014-06-12 | Jx Nippon Mining & Metals Corporation | Method for processing acidic solution that contains iodide ions and iron ions |
| CN101935847B (en) * | 2010-10-20 | 2012-10-17 | 昊华宇航化工有限责任公司 | Method for removing trace iodine from salt water for producing sodium hydroxide by electrolysis method |
| JP5718175B2 (en) * | 2011-06-21 | 2015-05-13 | Jx日鉱日石金属株式会社 | Elution method of iodine adsorbed on activated carbon |
| FR2991494B1 (en) | 2012-06-05 | 2020-01-31 | Korea Atomic Energy Research Institute | IODINE ABSORBING MATERIAL CONTAINING SALT AND RADIOACTIVE IODINE REMOVAL SYSTEM USING THE SAME |
| KR101636976B1 (en) * | 2012-06-05 | 2016-07-12 | 한국원자력연구원 | A iodine absorbent material containing salts and a radioactive iodine removal system using the same |
| RU2550405C2 (en) * | 2013-06-13 | 2015-05-10 | Общество с ограниченной ответственностью "Тюменская сырьевая компания" (ООО "ТСК") | Method of iodine extraction from confined groundwater |
| CN103305863B (en) * | 2013-06-19 | 2016-04-27 | 北京化工大学 | A kind of ion film caustic soda brine depth is except iodine method |
| CN103288201A (en) * | 2013-06-20 | 2013-09-11 | 哈尔滨工业大学 | Water treatment method for removing radioactive iodine pollution through combined use of persulfate and active carbon |
| CN103866348A (en) * | 2014-04-08 | 2014-06-18 | 重庆大学 | Method for removing trace iodine in chlor-alkali brine by using ozone |
| CN105293526A (en) * | 2015-10-26 | 2016-02-03 | 天津科技大学 | Method for purifying iodine in saline water of ionic membrane caustic soda production process |
| CN105293779B (en) * | 2015-11-24 | 2017-11-17 | 天津科技大学 | The cleaning equipment and operating method of iodine in ion film caustic soda production technology salt solution |
Family Cites Families (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US1944423A (en) * | 1927-03-05 | 1934-01-23 | Gen Salt Company | Recovery of iodine |
| DE3108991A1 (en) * | 1981-03-10 | 1982-09-23 | Gesellschaft für Strahlen- und Umweltforschung mbH, 8000 München | METHOD FOR SEPARATING AND COLLECTING IODINE |
| JPS59162285A (en) * | 1983-03-04 | 1984-09-13 | Asahi Chem Ind Co Ltd | Method for electrolyzing salt by ion exchange membrane method |
| JPH0712427B2 (en) * | 1985-11-14 | 1995-02-15 | 三菱重工業株式会社 | Manufacturing method of carbon monoxide adsorbent |
| JP2569124B2 (en) * | 1988-05-23 | 1997-01-08 | 三井東圧化学株式会社 | Method for recovering iodine from waste liquid containing organic iodine compound |
| IT1229724B (en) * | 1989-05-15 | 1991-09-07 | Solvay | PURIFICATION PROCEDURE OF A CHLORIDE AQUEOUS SOLUTION OF AN ALKALINE METAL FROM AMMONIAC AND IODATE COMPOUNDS. |
| JPH0416554A (en) * | 1990-05-07 | 1992-01-21 | Oki Electric Ind Co Ltd | Zirconium oxide-based solid solution and thermal head using same |
-
1992
- 1992-06-26 FR FR9207914A patent/FR2692879B1/en not_active Expired - Fee Related
-
1993
- 1993-06-17 NO NO19932247A patent/NO312505B1/en not_active IP Right Cessation
- 1993-06-18 AT AT93401568T patent/ATE135331T1/en not_active IP Right Cessation
- 1993-06-18 EP EP93401568A patent/EP0576335B1/en not_active Expired - Lifetime
- 1993-06-18 DE DE69301778T patent/DE69301778T2/en not_active Expired - Fee Related
- 1993-06-18 DK DK93401568.6T patent/DK0576335T3/en active
- 1993-06-18 ES ES93401568T patent/ES2087678T3/en not_active Expired - Lifetime
- 1993-06-24 FI FI932936A patent/FI932936A/en not_active IP Right Cessation
- 1993-06-25 CA CA002099184A patent/CA2099184C/en not_active Expired - Fee Related
- 1993-06-26 CN CN93109428A patent/CN1040738C/en not_active Expired - Fee Related
- 1993-06-26 KR KR1019930011782A patent/KR100237429B1/en not_active IP Right Cessation
- 1993-06-28 JP JP5181989A patent/JPH0791666B2/en not_active Expired - Fee Related
-
1996
- 1996-05-23 GR GR960401392T patent/GR3020029T3/en unknown
Also Published As
| Publication number | Publication date |
|---|---|
| JPH0791666B2 (en) | 1995-10-04 |
| DE69301778T2 (en) | 1996-10-02 |
| EP0576335B1 (en) | 1996-03-13 |
| FR2692879A1 (en) | 1993-12-31 |
| CN1084824A (en) | 1994-04-06 |
| EP0576335A1 (en) | 1993-12-29 |
| FI932936A0 (en) | 1993-06-24 |
| JPH0673588A (en) | 1994-03-15 |
| FI932936A (en) | 1993-12-27 |
| KR100237429B1 (en) | 2000-01-15 |
| CA2099184A1 (en) | 1993-12-27 |
| NO932247L (en) | 1993-12-30 |
| CN1040738C (en) | 1998-11-18 |
| KR940000370A (en) | 1994-01-03 |
| NO932247D0 (en) | 1993-06-17 |
| ES2087678T3 (en) | 1996-07-16 |
| FR2692879B1 (en) | 1994-12-02 |
| DK0576335T3 (en) | 1996-07-22 |
| CA2099184C (en) | 1999-10-12 |
| DE69301778D1 (en) | 1996-04-18 |
| ATE135331T1 (en) | 1996-03-15 |
| GR3020029T3 (en) | 1996-08-31 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| NO312505B1 (en) | Process for purifying an aqueous solution of alkali metal chloride to remove iodine | |
| RU2724779C1 (en) | Method for integrated processing of produced water of oil fields | |
| EP0143962B1 (en) | Process for removing aluminum and silica from alkali metal halide brine solutions | |
| US20080289972A1 (en) | Method of Purifying an Aqueous Solution | |
| US3929600A (en) | Process of removing ammoniacal nitrogen from waste water | |
| JP3021540B2 (en) | Purification method of alkali metal chloride aqueous solution | |
| US20150259765A1 (en) | Closed loop method for gold and silver extraction by halogens | |
| BG112342A (en) | Improved method of a closed cycle for extracting gold and silver through halogens | |
| JPH07237919A (en) | Method for purification of alkali metal chloride water solution and its plant | |
| JPH073485A (en) | Method for electrolyzing alkaline metal chloride | |
| RU2325469C2 (en) | Method for iodine or bromine recovery | |
| JP4436183B2 (en) | Iodine ion removal process and electrolysis process | |
| JP6369579B1 (en) | Method for removing silica from saline solution | |
| JPS6191014A (en) | Method of purifying aqueous solution of potassium chloride for electrolysis | |
| EP0609839B1 (en) | Method for electrolyzing an alkali metal chloride | |
| NO302465B1 (en) | Process for purifying an aqueous alkali metal chloride solution by removing iodine and optionally ammonium | |
| JP2023178802A (en) | Treatment method of cyanuric acid-containing wastewater | |
| JP3363762B2 (en) | Electrolysis method | |
| CA3229029A1 (en) | Method for lithium sorption extraction from lithium-containing brines | |
| SU1726379A1 (en) | Process for recovering lithium from natural water by ion exchange | |
| JPS5939185B2 (en) | How to remove mercury from solution | |
| JPH0448731B2 (en) | ||
| RU2113402C1 (en) | Method of isolating iodine from solutions | |
| JPH0716561A (en) | Treatment of fluorine-containing water | |
| JPS6356173B2 (en) |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| MM1K | Lapsed by not paying the annual fees |