US3899403A - Electrolytic method of making concentrated hydroxide solutions by sequential use of 3-compartment and 2-compartment electrolytic cells having separating compartment walls of particular cation-active permselective membranes - Google Patents
Electrolytic method of making concentrated hydroxide solutions by sequential use of 3-compartment and 2-compartment electrolytic cells having separating compartment walls of particular cation-active permselective membranes Download PDFInfo
- Publication number
- US3899403A US3899403A US411619A US41161973A US3899403A US 3899403 A US3899403 A US 3899403A US 411619 A US411619 A US 411619A US 41161973 A US41161973 A US 41161973A US 3899403 A US3899403 A US 3899403A
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- United States
- Prior art keywords
- compartment
- cells
- cathode
- cell
- sodium hydroxide
- Prior art date
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- Expired - Lifetime
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- 239000012528 membrane Substances 0.000 title claims abstract description 96
- XLYOFNOQVPJJNP-UHFFFAOYSA-M hydroxide Chemical compound [OH-] XLYOFNOQVPJJNP-UHFFFAOYSA-M 0.000 title claims abstract description 36
- 238000004519 manufacturing process Methods 0.000 title claims description 25
- HEMHJVSKTPXQMS-UHFFFAOYSA-M Sodium hydroxide Chemical compound [OH-].[Na+] HEMHJVSKTPXQMS-UHFFFAOYSA-M 0.000 claims abstract description 153
- 239000003518 caustics Substances 0.000 claims abstract description 77
- 239000000872 buffer Substances 0.000 claims abstract description 63
- 238000000034 method Methods 0.000 claims abstract description 63
- FAPWRFPIFSIZLT-UHFFFAOYSA-M Sodium chloride Chemical compound [Na+].[Cl-] FAPWRFPIFSIZLT-UHFFFAOYSA-M 0.000 claims abstract description 44
- 229920001577 copolymer Polymers 0.000 claims abstract description 34
- 230000008569 process Effects 0.000 claims abstract description 33
- 239000000460 chlorine Substances 0.000 claims abstract description 28
- ZAMOUSCENKQFHK-UHFFFAOYSA-N Chlorine atom Chemical compound [Cl] ZAMOUSCENKQFHK-UHFFFAOYSA-N 0.000 claims abstract description 26
- 229910052801 chlorine Inorganic materials 0.000 claims abstract description 26
- 239000011780 sodium chloride Substances 0.000 claims abstract description 22
- 229920001155 polypropylene Polymers 0.000 claims abstract description 19
- RRZIJNVZMJUGTK-UHFFFAOYSA-N 1,1,2-trifluoro-2-(1,2,2-trifluoroethenoxy)ethene Chemical class FC(F)=C(F)OC(F)=C(F)F RRZIJNVZMJUGTK-UHFFFAOYSA-N 0.000 claims abstract description 17
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims abstract description 17
- 229930195733 hydrocarbon Natural products 0.000 claims abstract description 14
- 150000002430 hydrocarbons Chemical class 0.000 claims abstract description 14
- 239000004215 Carbon black (E152) Substances 0.000 claims abstract description 12
- HQQADJVZYDDRJT-UHFFFAOYSA-N ethene;prop-1-ene Chemical group C=C.CC=C HQQADJVZYDDRJT-UHFFFAOYSA-N 0.000 claims abstract description 11
- 239000000243 solution Substances 0.000 claims description 76
- -1 polytetrafluoroethylene Polymers 0.000 claims description 30
- 239000000463 material Substances 0.000 claims description 27
- 229910000510 noble metal Inorganic materials 0.000 claims description 18
- BASFCYQUMIYNBI-UHFFFAOYSA-N platinum Chemical compound [Pt] BASFCYQUMIYNBI-UHFFFAOYSA-N 0.000 claims description 16
- RTAQQCXQSZGOHL-UHFFFAOYSA-N Titanium Chemical compound [Ti] RTAQQCXQSZGOHL-UHFFFAOYSA-N 0.000 claims description 14
- 239000007864 aqueous solution Substances 0.000 claims description 14
- 239000010936 titanium Substances 0.000 claims description 13
- 229910052719 titanium Inorganic materials 0.000 claims description 13
- 239000000203 mixture Substances 0.000 claims description 12
- 239000003792 electrolyte Substances 0.000 claims description 11
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 claims description 10
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 claims description 10
- 239000001257 hydrogen Substances 0.000 claims description 10
- 229910052739 hydrogen Inorganic materials 0.000 claims description 10
- 229910000831 Steel Inorganic materials 0.000 claims description 9
- 150000004706 metal oxides Chemical class 0.000 claims description 9
- 229920001343 polytetrafluoroethylene Polymers 0.000 claims description 9
- 239000010959 steel Substances 0.000 claims description 9
- 239000004743 Polypropylene Substances 0.000 claims description 8
- 239000004810 polytetrafluoroethylene Substances 0.000 claims description 8
- BFKJFAAPBSQJPD-UHFFFAOYSA-N tetrafluoroethene Chemical group FC(F)=C(F)F BFKJFAAPBSQJPD-UHFFFAOYSA-N 0.000 claims description 8
- 229910052697 platinum Inorganic materials 0.000 claims description 7
- 229910052751 metal Inorganic materials 0.000 claims description 6
- 239000002184 metal Substances 0.000 claims description 6
- 229910001925 ruthenium oxide Inorganic materials 0.000 claims description 6
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 claims description 5
- KJTLSVCANCCWHF-UHFFFAOYSA-N Ruthenium Chemical compound [Ru] KJTLSVCANCCWHF-UHFFFAOYSA-N 0.000 claims description 5
- 239000010425 asbestos Substances 0.000 claims description 5
- 229910002804 graphite Inorganic materials 0.000 claims description 5
- 239000010439 graphite Substances 0.000 claims description 5
- 229910052742 iron Inorganic materials 0.000 claims description 5
- 229910052895 riebeckite Inorganic materials 0.000 claims description 5
- WOCIAKWEIIZHES-UHFFFAOYSA-N ruthenium(iv) oxide Chemical compound O=[Ru]=O WOCIAKWEIIZHES-UHFFFAOYSA-N 0.000 claims description 5
- 229910045601 alloy Inorganic materials 0.000 claims description 4
- 239000000956 alloy Substances 0.000 claims description 4
- 229910052707 ruthenium Inorganic materials 0.000 claims description 4
- 229910052715 tantalum Inorganic materials 0.000 claims description 4
- GUVRBAGPIYLISA-UHFFFAOYSA-N tantalum atom Chemical compound [Ta] GUVRBAGPIYLISA-UHFFFAOYSA-N 0.000 claims description 4
- 229910052741 iridium Inorganic materials 0.000 claims description 3
- GKOZUEZYRPOHIO-UHFFFAOYSA-N iridium atom Chemical compound [Ir] GKOZUEZYRPOHIO-UHFFFAOYSA-N 0.000 claims description 3
- 229910044991 metal oxide Inorganic materials 0.000 claims description 3
- 229910052758 niobium Inorganic materials 0.000 claims description 3
- 239000010955 niobium Substances 0.000 claims description 3
- GUCVJGMIXFAOAE-UHFFFAOYSA-N niobium atom Chemical compound [Nb] GUCVJGMIXFAOAE-UHFFFAOYSA-N 0.000 claims description 3
- 229910052703 rhodium Inorganic materials 0.000 claims description 3
- 239000010948 rhodium Substances 0.000 claims description 3
- MHOVAHRLVXNVSD-UHFFFAOYSA-N rhodium atom Chemical compound [Rh] MHOVAHRLVXNVSD-UHFFFAOYSA-N 0.000 claims description 3
- 238000005868 electrolysis reaction Methods 0.000 abstract description 11
- 210000004027 cell Anatomy 0.000 description 135
- 210000004379 membrane Anatomy 0.000 description 87
- XTEGARKTQYYJKE-UHFFFAOYSA-M Chlorate Chemical compound [O-]Cl(=O)=O XTEGARKTQYYJKE-UHFFFAOYSA-M 0.000 description 27
- 235000002639 sodium chloride Nutrition 0.000 description 24
- 239000000047 product Substances 0.000 description 13
- 229920000728 polyester Polymers 0.000 description 11
- VEXZGXHMUGYJMC-UHFFFAOYSA-M Chloride anion Chemical compound [Cl-] VEXZGXHMUGYJMC-UHFFFAOYSA-M 0.000 description 9
- YMWUJEATGCHHMB-UHFFFAOYSA-N Dichloromethane Chemical compound ClCCl YMWUJEATGCHHMB-UHFFFAOYSA-N 0.000 description 9
- PPBRXRYQALVLMV-UHFFFAOYSA-N Styrene Chemical compound C=CC1=CC=CC=C1 PPBRXRYQALVLMV-UHFFFAOYSA-N 0.000 description 8
- 229920000642 polymer Polymers 0.000 description 8
- 238000011282 treatment Methods 0.000 description 8
- 229920009441 perflouroethylene propylene Polymers 0.000 description 7
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 description 6
- 241000196324 Embryophyta Species 0.000 description 6
- VEXZGXHMUGYJMC-UHFFFAOYSA-N Hydrochloric acid Chemical compound Cl VEXZGXHMUGYJMC-UHFFFAOYSA-N 0.000 description 6
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 6
- 239000004020 conductor Substances 0.000 description 6
- 229910052802 copper Inorganic materials 0.000 description 6
- 239000010949 copper Substances 0.000 description 6
- 239000004744 fabric Substances 0.000 description 6
- 239000010408 film Substances 0.000 description 6
- 239000001301 oxygen Substances 0.000 description 6
- 229910052760 oxygen Inorganic materials 0.000 description 6
- 238000002474 experimental method Methods 0.000 description 5
- 125000001997 phenyl group Chemical group [H]C1=C([H])C([H])=C(*)C([H])=C1[H] 0.000 description 5
- 229940058401 polytetrafluoroethylene Drugs 0.000 description 5
- 150000003839 salts Chemical class 0.000 description 5
- WCUXLLCKKVVCTQ-UHFFFAOYSA-M Potassium chloride Chemical class [Cl-].[K+] WCUXLLCKKVVCTQ-UHFFFAOYSA-M 0.000 description 4
- 239000012267 brine Substances 0.000 description 4
- 238000006243 chemical reaction Methods 0.000 description 4
- OSVXSBDYLRYLIG-UHFFFAOYSA-N dioxidochlorine(.) Chemical compound O=Cl=O OSVXSBDYLRYLIG-UHFFFAOYSA-N 0.000 description 4
- 230000007062 hydrolysis Effects 0.000 description 4
- 238000006460 hydrolysis reaction Methods 0.000 description 4
- WQYVRQLZKVEZGA-UHFFFAOYSA-N hypochlorite Chemical compound Cl[O-] WQYVRQLZKVEZGA-UHFFFAOYSA-N 0.000 description 4
- 239000004033 plastic Substances 0.000 description 4
- 229920003023 plastic Polymers 0.000 description 4
- 238000004076 pulp bleaching Methods 0.000 description 4
- 230000003134 recirculating effect Effects 0.000 description 4
- 238000011160 research Methods 0.000 description 4
- HPALAKNZSZLMCH-UHFFFAOYSA-M sodium;chloride;hydrate Chemical compound O.[Na+].[Cl-] HPALAKNZSZLMCH-UHFFFAOYSA-M 0.000 description 4
- 239000000126 substance Substances 0.000 description 4
- UHOVQNZJYSORNB-UHFFFAOYSA-N Benzene Chemical compound C1=CC=CC=C1 UHOVQNZJYSORNB-UHFFFAOYSA-N 0.000 description 3
- GWEVSGVZZGPLCZ-UHFFFAOYSA-N Titan oxide Chemical compound O=[Ti]=O GWEVSGVZZGPLCZ-UHFFFAOYSA-N 0.000 description 3
- 125000004432 carbon atom Chemical group C* 0.000 description 3
- 150000001768 cations Chemical class 0.000 description 3
- XTEGARKTQYYJKE-UHFFFAOYSA-N chloric acid Chemical compound OCl(=O)=O XTEGARKTQYYJKE-UHFFFAOYSA-N 0.000 description 3
- 230000006835 compression Effects 0.000 description 3
- 238000007906 compression Methods 0.000 description 3
- 238000010276 construction Methods 0.000 description 3
- 230000003292 diminished effect Effects 0.000 description 3
- 239000000835 fiber Substances 0.000 description 3
- 238000012986 modification Methods 0.000 description 3
- 230000004048 modification Effects 0.000 description 3
- 235000011164 potassium chloride Nutrition 0.000 description 3
- 238000004537 pulping Methods 0.000 description 3
- 230000005855 radiation Effects 0.000 description 3
- 239000012266 salt solution Substances 0.000 description 3
- 239000000758 substrate Substances 0.000 description 3
- DJKGDNKYTKCJKD-BPOCMEKLSA-N (1s,4r,5s,6r)-1,2,3,4,7,7-hexachlorobicyclo[2.2.1]hept-2-ene-5,6-dicarboxylic acid Chemical compound ClC1=C(Cl)[C@]2(Cl)[C@H](C(=O)O)[C@H](C(O)=O)[C@@]1(Cl)C2(Cl)Cl DJKGDNKYTKCJKD-BPOCMEKLSA-N 0.000 description 2
- KEQGZUUPPQEDPF-UHFFFAOYSA-N 1,3-dichloro-5,5-dimethylimidazolidine-2,4-dione Chemical compound CC1(C)N(Cl)C(=O)N(Cl)C1=O KEQGZUUPPQEDPF-UHFFFAOYSA-N 0.000 description 2
- 239000004155 Chlorine dioxide Substances 0.000 description 2
- HEDRZPFGACZZDS-UHFFFAOYSA-N Chloroform Chemical compound ClC(Cl)Cl HEDRZPFGACZZDS-UHFFFAOYSA-N 0.000 description 2
- RTZKZFJDLAIYFH-UHFFFAOYSA-N Diethyl ether Chemical compound CCOCC RTZKZFJDLAIYFH-UHFFFAOYSA-N 0.000 description 2
- 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 description 2
- TWRXJAOTZQYOKJ-UHFFFAOYSA-L Magnesium chloride Chemical compound [Mg+2].[Cl-].[Cl-] TWRXJAOTZQYOKJ-UHFFFAOYSA-L 0.000 description 2
- 229920001328 Polyvinylidene chloride Polymers 0.000 description 2
- 229920001131 Pulp (paper) Polymers 0.000 description 2
- BQCADISMDOOEFD-UHFFFAOYSA-N Silver Chemical compound [Ag] BQCADISMDOOEFD-UHFFFAOYSA-N 0.000 description 2
- QAOWNCQODCNURD-UHFFFAOYSA-N Sulfuric acid Chemical compound OS(O)(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-N 0.000 description 2
- 230000002378 acidificating effect Effects 0.000 description 2
- 229910001508 alkali metal halide Inorganic materials 0.000 description 2
- 150000008045 alkali metal halides Chemical class 0.000 description 2
- 229910052782 aluminium Inorganic materials 0.000 description 2
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 2
- 230000008901 benefit Effects 0.000 description 2
- 239000007844 bleaching agent Substances 0.000 description 2
- 210000002421 cell wall Anatomy 0.000 description 2
- 235000019398 chlorine dioxide Nutrition 0.000 description 2
- XTHPWXDJESJLNJ-UHFFFAOYSA-N chlorosulfonic acid Substances OS(Cl)(=O)=O XTHPWXDJESJLNJ-UHFFFAOYSA-N 0.000 description 2
- 238000001816 cooling Methods 0.000 description 2
- 230000007423 decrease Effects 0.000 description 2
- YADSGOSSYOOKMP-UHFFFAOYSA-N dioxolead Chemical compound O=[Pb]=O YADSGOSSYOOKMP-UHFFFAOYSA-N 0.000 description 2
- 229920001971 elastomer Polymers 0.000 description 2
- 125000002887 hydroxy group Chemical group [H]O* 0.000 description 2
- 238000009434 installation Methods 0.000 description 2
- 239000007788 liquid Substances 0.000 description 2
- 239000002609 medium Substances 0.000 description 2
- 150000002739 metals Chemical class 0.000 description 2
- 238000013508 migration Methods 0.000 description 2
- 230000005012 migration Effects 0.000 description 2
- 230000020477 pH reduction Effects 0.000 description 2
- 229910003446 platinum oxide Inorganic materials 0.000 description 2
- 229920000915 polyvinyl chloride Polymers 0.000 description 2
- 239000004800 polyvinyl chloride Substances 0.000 description 2
- 239000005033 polyvinylidene chloride Substances 0.000 description 2
- 230000003716 rejuvenation Effects 0.000 description 2
- 239000005060 rubber Substances 0.000 description 2
- 229920006395 saturated elastomer Polymers 0.000 description 2
- 229910052709 silver Inorganic materials 0.000 description 2
- 239000004332 silver Substances 0.000 description 2
- 229910052708 sodium Inorganic materials 0.000 description 2
- 239000011734 sodium Substances 0.000 description 2
- 239000007787 solid Substances 0.000 description 2
- OGIDPMRJRNCKJF-UHFFFAOYSA-N titanium oxide Inorganic materials [Ti]=O OGIDPMRJRNCKJF-UHFFFAOYSA-N 0.000 description 2
- BZSXEZOLBIJVQK-UHFFFAOYSA-N 2-methylsulfonylbenzoic acid Chemical compound CS(=O)(=O)C1=CC=CC=C1C(O)=O BZSXEZOLBIJVQK-UHFFFAOYSA-N 0.000 description 1
- WKBOTKDWSSQWDR-UHFFFAOYSA-N Bromine atom Chemical compound [Br] WKBOTKDWSSQWDR-UHFFFAOYSA-N 0.000 description 1
- KZBUYRJDOAKODT-UHFFFAOYSA-N Chlorine Chemical compound ClCl KZBUYRJDOAKODT-UHFFFAOYSA-N 0.000 description 1
- VGGSQFUCUMXWEO-UHFFFAOYSA-N Ethene Chemical compound C=C VGGSQFUCUMXWEO-UHFFFAOYSA-N 0.000 description 1
- 239000005977 Ethylene Substances 0.000 description 1
- 229920004546 Hetron™ Polymers 0.000 description 1
- 229910001209 Low-carbon steel Inorganic materials 0.000 description 1
- 239000004677 Nylon Substances 0.000 description 1
- 229920001774 Perfluoroether Polymers 0.000 description 1
- 240000005428 Pistacia lentiscus Species 0.000 description 1
- ZLMJMSJWJFRBEC-UHFFFAOYSA-N Potassium Chemical compound [K] ZLMJMSJWJFRBEC-UHFFFAOYSA-N 0.000 description 1
- FKNQFGJONOIPTF-UHFFFAOYSA-N Sodium cation Chemical compound [Na+] FKNQFGJONOIPTF-UHFFFAOYSA-N 0.000 description 1
- 239000004809 Teflon Substances 0.000 description 1
- 229920006362 Teflon® Polymers 0.000 description 1
- 239000002253 acid Substances 0.000 description 1
- 239000000654 additive Substances 0.000 description 1
- 230000000996 additive effect Effects 0.000 description 1
- 229910001514 alkali metal chloride Inorganic materials 0.000 description 1
- 150000008044 alkali metal hydroxides Chemical class 0.000 description 1
- 125000000217 alkyl group Chemical group 0.000 description 1
- 239000012736 aqueous medium Substances 0.000 description 1
- 239000002585 base Substances 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 230000033228 biological regulation Effects 0.000 description 1
- 230000005540 biological transmission Effects 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- GDTBXPJZTBHREO-UHFFFAOYSA-N bromine Substances BrBr GDTBXPJZTBHREO-UHFFFAOYSA-N 0.000 description 1
- 229910052794 bromium Inorganic materials 0.000 description 1
- 239000007853 buffer solution Substances 0.000 description 1
- 239000006227 byproduct Substances 0.000 description 1
- 125000002091 cationic group Chemical group 0.000 description 1
- 210000005056 cell body Anatomy 0.000 description 1
- 239000007795 chemical reaction product Substances 0.000 description 1
- 239000003795 chemical substances by application Substances 0.000 description 1
- 150000001805 chlorine compounds Chemical class 0.000 description 1
- 229910017052 cobalt Inorganic materials 0.000 description 1
- 239000010941 cobalt Substances 0.000 description 1
- GUTLYIVDDKVIGB-UHFFFAOYSA-N cobalt atom Chemical compound [Co] GUTLYIVDDKVIGB-UHFFFAOYSA-N 0.000 description 1
- 239000002131 composite material Substances 0.000 description 1
- 150000001875 compounds Chemical class 0.000 description 1
- 238000010924 continuous production Methods 0.000 description 1
- 238000002425 crystallisation Methods 0.000 description 1
- 230000008025 crystallization Effects 0.000 description 1
- 230000003247 decreasing effect Effects 0.000 description 1
- 238000011161 development Methods 0.000 description 1
- 238000007865 diluting Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 125000001495 ethyl group Chemical group [H]C([H])([H])C([H])([H])* 0.000 description 1
- 238000001704 evaporation Methods 0.000 description 1
- 230000008020 evaporation Effects 0.000 description 1
- 239000002360 explosive Substances 0.000 description 1
- UQSQSQZYBQSBJZ-UHFFFAOYSA-N fluorosulfonic acid Chemical compound OS(F)(=O)=O UQSQSQZYBQSBJZ-UHFFFAOYSA-N 0.000 description 1
- 239000000446 fuel Substances 0.000 description 1
- 238000007499 fusion processing Methods 0.000 description 1
- 239000011521 glass Substances 0.000 description 1
- 150000004820 halides Chemical class 0.000 description 1
- 229910052736 halogen Inorganic materials 0.000 description 1
- 150000002367 halogens Chemical class 0.000 description 1
- HCDGVLDPFQMKDK-UHFFFAOYSA-N hexafluoropropylene Chemical group FC(F)=C(F)C(F)(F)F HCDGVLDPFQMKDK-UHFFFAOYSA-N 0.000 description 1
- 150000002431 hydrogen Chemical class 0.000 description 1
- 150000004679 hydroxides Chemical class 0.000 description 1
- 239000012535 impurity Substances 0.000 description 1
- 238000010348 incorporation Methods 0.000 description 1
- 238000005342 ion exchange Methods 0.000 description 1
- 150000002500 ions Chemical class 0.000 description 1
- 230000001788 irregular Effects 0.000 description 1
- 239000006193 liquid solution Substances 0.000 description 1
- 229910001629 magnesium chloride Inorganic materials 0.000 description 1
- 239000000178 monomer Substances 0.000 description 1
- 230000007935 neutral effect Effects 0.000 description 1
- SNICXCGAKADSCV-UHFFFAOYSA-N nicotine Chemical compound CN1CCCC1C1=CC=CN=C1 SNICXCGAKADSCV-UHFFFAOYSA-N 0.000 description 1
- 229920001778 nylon Polymers 0.000 description 1
- MUMZUERVLWJKNR-UHFFFAOYSA-N oxoplatinum Chemical compound [Pt]=O MUMZUERVLWJKNR-UHFFFAOYSA-N 0.000 description 1
- JVUFZBJAJZPEOQ-UHFFFAOYSA-N oxoruthenium(1+) oxygen(2-) titanium(4+) Chemical group [O-2].[O-2].[Ti+4].[Ru+]=O JVUFZBJAJZPEOQ-UHFFFAOYSA-N 0.000 description 1
- UJMWVICAENGCRF-UHFFFAOYSA-N oxygen difluoride Chemical compound FOF UJMWVICAENGCRF-UHFFFAOYSA-N 0.000 description 1
- SOQBVABWOPYFQZ-UHFFFAOYSA-N oxygen(2-);titanium(4+) Chemical class [O-2].[O-2].[Ti+4] SOQBVABWOPYFQZ-UHFFFAOYSA-N 0.000 description 1
- 230000000149 penetrating effect Effects 0.000 description 1
- 229920001568 phenolic resin Polymers 0.000 description 1
- 229920001084 poly(chloroprene) Polymers 0.000 description 1
- 229910052700 potassium Inorganic materials 0.000 description 1
- 239000011591 potassium Substances 0.000 description 1
- 239000001103 potassium chloride Substances 0.000 description 1
- 239000002244 precipitate Substances 0.000 description 1
- 238000003825 pressing Methods 0.000 description 1
- 238000012545 processing Methods 0.000 description 1
- 230000000135 prohibitive effect Effects 0.000 description 1
- 125000002572 propoxy group Chemical group [*]OC([H])([H])C(C([H])([H])[H])([H])[H] 0.000 description 1
- 125000001436 propyl group Chemical group [H]C([*])([H])C([H])([H])C([H])([H])[H] 0.000 description 1
- 238000005057 refrigeration Methods 0.000 description 1
- 230000001105 regulatory effect Effects 0.000 description 1
- 229930195734 saturated hydrocarbon Natural products 0.000 description 1
- 229910001415 sodium ion Inorganic materials 0.000 description 1
- 238000006467 substitution reaction Methods 0.000 description 1
- 238000006277 sulfonation reaction Methods 0.000 description 1
- 125000000472 sulfonyl group Chemical group *S(*)(=O)=O 0.000 description 1
- HIFJUMGIHIZEPX-UHFFFAOYSA-N sulfuric acid;sulfur trioxide Chemical compound O=S(=O)=O.OS(O)(=O)=O HIFJUMGIHIZEPX-UHFFFAOYSA-N 0.000 description 1
- 238000004381 surface treatment Methods 0.000 description 1
- 229920001169 thermoplastic Polymers 0.000 description 1
- 239000004416 thermosoftening plastic Substances 0.000 description 1
- 230000008719 thickening Effects 0.000 description 1
- 239000010409 thin film Substances 0.000 description 1
- 239000004408 titanium dioxide Substances 0.000 description 1
- 238000004448 titration Methods 0.000 description 1
- 229920011532 unplasticized polyvinyl chloride Polymers 0.000 description 1
- 229930195735 unsaturated hydrocarbon Natural products 0.000 description 1
Images
Classifications
-
- C—CHEMISTRY; METALLURGY
- C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
- C25B—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES FOR THE PRODUCTION OF COMPOUNDS OR NON-METALS; APPARATUS THEREFOR
- C25B13/00—Diaphragms; Spacing elements
- C25B13/02—Diaphragms; Spacing elements characterised by shape or form
-
- C—CHEMISTRY; METALLURGY
- C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
- C25B—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES FOR THE PRODUCTION OF COMPOUNDS OR NON-METALS; APPARATUS THEREFOR
- C25B1/00—Electrolytic production of inorganic compounds or non-metals
- C25B1/01—Products
- C25B1/24—Halogens or compounds thereof
- C25B1/26—Chlorine; Compounds thereof
Definitions
- a concentrated hydroxide solution containing over 250 g./l. of sodium hydroxide is made by a two-cell aqueous sodium chloride electrolysis process wherein, in a first cell, containing at least three (and preferably three) compartments, with a buffer compartment separated from adjoining anode and cathode compartments by walls of a cation-active permselective mem brane, which is of aliydrolyzed copolymer of a perfluorinated hydrocarbon and fluorosulfonated perfluorovinyl ether or of a sulfostyrenated perfluorinated ethylene propylene polymer, a concentrated sodium hydroxide solution is made in the cathode compartment, a dilute sodium hydroxide solution is produced in a buffer compartment, to which compartment water is added during the electrolysis and
- This invention relates to the electrolytic manufacture of hydroxide solutions. More specifically, it is of a process for making alkali metal hydroxides in concentrated liquid solution form by the electrolysis of aqueous alkali metal halide solutions in two different types of electrolytic cells, each of which'utilizes one or more cation-active permselective membranes of a particular type.
- Chlorine and caustic are essential and large volume commodities which are required basic chemicals in all industrial societies. They are commercially produced by electrolysis of aqueous salt solutions and a major proportion of such production is by diaphragm cells. Such cells have been improved by incorporation therein of dimensionally stable anodes, which include noble metals, alloys or oxides thereof or mixtures thereof, on valve metals.
- the present method allows the utilization of the dilute caustic inthe manufacture of a more concentrated sodium hydroxide solution so that, even if there is no nearby plant or other installation which can utilize the dilute caustic enough water has been removed from it to allow it to be marketed as an article of commerce and to be economically shipped over long distances.
- a method for electrolytically manufacturing concentrated hydroxide solutions containing over 250 g./l. of sodium hydroxide or equivalent hydroxide comprises making concentrated and dilute aqueous hydroxide solutions simultaneously by electrolyzing an aqueous solution containing halide ions in an electrolytic cell having at least three compartments therein, an anode, a cathode, at least two cation-active permselective membranes, of a polymeric materialselected from the group consisting of a hydrolyzed copolymer of a'perfluorinated hydrocarbon and a fluorosulfonated perfluorovinyl ether and a sulfostyrenated perfluorinated” ethylene proplyene polymer, defining anode and cathode side walls of a buffer compartment or compartments between anode and cathode compartments, and such walls, with walls thereab'out, defining anode and cathode compartments, while adding waterw
- a two-compartment electrolytic cell having anode and cathode compartments separated by a cation-active permselective membrane of a polymeric material selected from-the group consisting of a hydrolyzed copolymer of a perfluorinated hydrocarbon and a fluorosulfonatedperfluorovinyl ether, and a sulfostyrenated perfluorinated ethylene propylene polymer, in which cell, in the anode compartment thereof, an aqueous solution containing halide ions is electrolyzed, and withdrawing from the catholyte compartment of the two-compartment cell concentrated hydroxide solution containing more than 250 g./l.
- electrolytic cell ll includes outer wall 13, anode 15, cathode 17 and conductive means 19 and 21 for connecting the anode and the cathode to sources of positive and negative electrical potentials, respectively.
- permselective membranes 23 and 25 divide the volume into anode or anolyte compartment 27, cathode or catholyte compartment 29 and buffer compartment 31.
- An aqueous solution of alkali metal halide, preferably acidic, is fed to the anolyte compartment through line 33, from saturator 35.
- chlorine gas is removed from above the anode compartment through line 37 and hydrogen gas is correspondingly removed from above the cathode compartment through line 39.
- More concentrated hydroxide solution is withdrawn from cathode compartment 29 through line 41 while the corresponding solution of lower concentration is withdrawn from the buffer compartment through line 43 and is delivered to the cathode compartment 45 of twocompartment cell 47.
- Water may be added to buffer compartment 31 of three-compartment cell 11 through line 49 to maintain the desired concentration of caustic in that compartment so as to maintain a high current efficiency, cathode efficiency, cathode compartment efficency, caustic efficiency or sodium ion efficiency (all such terms being interchangeable) by limiting the transmission of hydroxyl ions to the anolyte through membrane 23.
- Solid sodium chloride or other source of chloride ions may be fed to saturator through line 51 to raise the chloride concentration in the feed to the cells.
- the anolytes may be recirculated back to the saturator for addition of salt to maintain the desired concentration thereof in the anolyte.
- Proportioning valve 53 controls the flow of rejuvenated electrolyte to anolyte compartments 27 and 55 through lines 33' and 75.
- anode 57 is connected to a source of positive electrical potential via conductor 59 and cathode 61 is similarly connected via a corresponding conductor 63.
- Cationactive permselective membrane 65 separates compartments and 55.
- Low concentration sodium hydroxide solution from buffer compartment 31 passes through line 67 into cathode compartment 45 to add its hydroxyl ion content to that produced in the two-compartment cell by electrolysis thereof.
- a high concentration sodium hydroxide solution is produced in cathode compartment 45 and is withdrawn from it through line 69.
- Chlorine and hydrogen are withdrawn from the anode and cathode compartments, respectively, through lines 71 and 73.
- the high concentration sodium hydroxide solution produced may be sold, employed in chemical reactions, e.g., making chlorate, or may be evaporated to still higher concentrations.
- the chlorine may be reacted with the caustic to form hypochlorite or chlorate or may be reacted with hydrogen made to produce hydrochloric acid. Otherwise, it is salable, usually after liquefaction, in which process any oxygen present is removed.
- the chlorine, hydrogen and high concentration caustic solution streams from the three-compartment and two-compartment cells may be kept separate or may be combined.
- anolyte will be recirculated back to the saturator and if the chlorate concentration therein becomes too high, due to reaction of chlorine with caustic in the anode compartment of the twocompartment cell, some of the anolyte may be sent to a separator or crystallizer for removal of the chlorate, preferably, in crystalline form, or it may be fed as a chlorate cell electrolyte.
- caustic current efficiency e.g., over or in the threecompartment cell
- the chlorine produced contains less oxygen and the electric power is utilized more for the production of caustic than in two-compartment cells.
- caustic current efficiencies of only 50 or 60% (or more) are obtainable but there is no dilute caustic byproduct, all of the caustic solution being produced as saltfree high concentration caustic.
- the overall efficiency of the process is generally over 70% and often over 75%, a startling increase over the 50 or 60% efficiencies obtainable when utilizing the two-compartment cell alone to make strong caustic.
- the feed from one three-compartment cell is shown going to a single two-compartment cell.
- a plurality of three-compartment cells may be headed together, both with respect to feeds and products, and the products may be fed to a plurality of twocompartment cells.
- the high concentration catholyte hydroxide removed is at a concentration over 250 g./l., preferably over 350 g./l.
- the dilute caustic taken off from the buffer compartment is at a concentration over 20 g./l. and is usually in the 50 to 200 g./l. range, preferably being over 75 g./l., more preferably being from lOO to g./l. and most preferably being about l25 g./l.
- the preferred embodiments of the invention utilize a pair of the described membranes to form the three compartments of the present three compartment cells it will be evident that a greater num ber of compartments, e.g., 4 to 6, including plural buffer zones, may be employed.
- a greater num ber of compartments e.g., 4 to 6, including plural buffer zones
- the cell compartments of both types of cells will usually be separated by flat membranes and will usually be of substantially rectilinear or parallelepipedal construction, various other shapes, including curves, e.g., ellipsoids, and irregular surfaces, e.g., sawtoothed or plurally pointed walls, may also be utilized.
- the buffer zone(s), formed by the plurality of membranes will be between bipolar electrodes, rather than the monopolar electrodes which are described herein.
- Bipolar electrodes may also be employed for the twocompartment cells.
- Those of skill in the art will know the variations in structure that will be made to accommodate bipolar, rather than monopolar electrodes, and therefore, these will not be described in detail.
- pluralities of the individual cells will be employed in multi-cell units, often having common feed and productmanifolds and being housed in unitary structures. Again, such constructions are known to those in the art and need not be discussed herein.
- the volume of the buffer compartment(s) will usually be from 1 to 100%, preferably from 5 to 70% that of the sum of the volumes of the anode and cathode compart ments.
- the aqueous solution containing chloride ions is normally a water solution of sodium chloride, although potassium and other soluble chlorides, e.g., magnesium chloride, sometimes also may be utilized, at least in part. However, it is preferable to employ the alkali metal chlorides and of these sodium chloride is the best.
- Sodium and potassium chlorides include cations which do not form insoluble salts or precipitates and which produce stable hydroxides.
- the concentration of sodium chloride in a brine charged will usually be as high as feasible, normally being from 200 to 320 grams per liter for sodium chloride and from 200 to 360 g./l. for potassium chloride, with intermediate figures for mixtures of sodium and potassium chlorides.
- the electrolyte may be neutral or acidified to a pH in the range of about 1 to 6, acidification normally being effected with a suitable acid such as hydrochloric acid.
- Charging of the brine is to the anolyte compartment, usually at a concentration of 200 to 320 g./l., most preferably of 250 to 300 g./l.
- Intracompartmental recirculations of the various compartment contents are often desirable to maintain the concentrations uniform throughout.
- the presently preferred cation permselective membrane is of a hydrolyzed copolymer of perfluorinated hydrocarbon and a fluorosulfonated perfluorovinyl ether.
- the perfluorinated hydrocarbon is preferably tetrafluoroethylene, although other perfluorinated and saturated and unsaturated hydrocarbons of 2 to 5 carbon atoms may also be utilized, of which the monoolefinic hydrocarbons are preferred, especially those of 2 to 4 carbon atoms and most especially those of 2 to 3 carbon atoms, e.g., tetrafluoroethylene, hexafluoropropylene.
- PSEPVE perfluoro[2-(2-fluorosulfonylethoxy)-propyl vinyl ether]
- PSEPVE perfluoro[2-(2-fluorosulfonylethoxy)-propyl vinyl ether]
- PSEPVE perfluoro[2-(2-fluorosulfonylethoxy)-propyl vinyl ether]
- PSEPVE perfluoro[2-(2-fluorosulfonylethoxy)-propyl vinyl ether]
- PSEPVE perfluoro[2-(2-fluorosulfonylethoxy)-propyl vinyl ether]
- the copolymer may be made by reacting PSEPVE or equivalent with tetrafluoroethyleneor equivalent in desired proportions in water at elevated temperature and pressure for over an hour, after which time the mix is cooled. It separates into a lower perfluoroether layer and an upper layer of aqueous medium with dispersed desired polymer.
- the molecular weight is indeterminate butithe equivalent weight is about 900 to 1,600 preferably l,l00 to 1,400 and the percentage of PSEPVE or corresponding compound is about 10 to 30%, preferably l5 to 20% and most preferably about 17%.
- the unhydrolyzed copolymer may be compression molded at high temperature and pressure to produce sheets or membranes, which may vary in thickness from 0.02 to 0.5 mm. These are then further treated to hydrolyze pendant SO F groups to SO;,H groups, as by treating with 10% sulfuric acid or by the methods of the patents previously mentioned. The presence of the SO,,H groups may be verified by titration, as described in the Canadian patent. Additional details of various processing steps are described in Canadian Pat. No. 752,427 and US. Pat. No. 3,041,317, also hereby incorporated by reference.
- the copolymer membrane is preferably joined to the backing tetrafluoroethylene or other-suitable filaments prior to hydrolysis, when it is still thermoplastic; and the film of copolymer covers each filament, penetrating into the spaces between them and even around behind them, thinning the films slightly in the process, where they cover the filaments.
- the membrane described is far superior in the present processes to all other previously suggested membrane materials. It is more stable at elevated temperatures, e.g., above C. It lasts for much longer time periods in the medium of the electrolyte and the caustic product and does not become brittle when subjected to chlorine at high cell'ter'nperatures. Considering the savings in time and fabrication costs, the present membranes are more economical. The voltage drop through the membranes is acceptable and does not become inordinately high, as it does with many other membrane materials, when the caustic concentration in the cathode compartment increases to above about 200 g./l. of caustic.
- the selectivity of the membrane and its compatibility with the electrolyte do not decrease detrimentally as the hydroxyl concentration in the catholyte liquor increases, as has been noted with other membrane materials. Furthermore, the caustic efficiency of the electrolysis does not diminish as significantly as it does with other membranes when the hydroxyl ion concentration in the catholyte increases. Thus, these differences in the present process make it practicable, whereas previously described processes have not at tained commercial-acceptance. While the more preferred copolymers are those having equivalent weights of 900 to 1,600, with 1,100 to 1,400 being most preferred, some useful resinous membranes produced by the present method may be of equivalent weights from 500 to 4,000. The medium equivalent weight polymers are preferred because they are of satisfactory strength and stability, enable better selective ion exchange to take place and are of lower internal resistances, all of which are important to the present electrochemical cell.
- Improved versions of the above-described copolymers may be made by chemical treatment of surfaces thereof, as by treatments to modify the -SO l-l group thereon.
- the sulfonic group may be altered on the membrane to produce a concentration gradient or may be replaced in part with a phosphoric or phosphonic moiety.
- Such changes may be made in the manufacturing process or after production of the membrane.
- the depth of treatment will usually be from 0.001 to 0.01 mm.
- Caustic efficiencies of the invented processes, using such modified versions of the present improved membranes can increase about 3 to 20%, often about to Exemplary of such treatments is that described in French patent publication 2,152,194 of Mar. 26, 1973 in which one side of the membrane is treated with Nl-l to form SO Nl-l groups.
- sulfostyrenated FEP membranes To manufacture the sulfostyrenated FEP membranes a standard FEP, such as manufacture by E. I. DuPont de Nemours & Co., Inc., is styrenated and the styrenated polymer is then sulfonated.
- a solution of styrene in methylene chloride or benzene at a suitable concentration in the range of about 10 to is prepared and a sheet of PEP polymer having a thickness of about 0.02 to 0.5 mm., preferably 0.05 to 0.15 mm., is dipped into the solution. After removal it is subjected to radiation treatment, using a cobalt radiation source.
- the rate of application may be in the range of about 8,000 rads/hr.
- the phenyl rings of the styrene portion of the polymer are monosulfonated, preferably in he para position, by treatment with chlorosulfonic acid, fuming sulfuric acid or S0
- chlorosulfonic acid in chloroform is utilized and the sulfonation is completed in about /2 hour.
- Examples of useful membranes made by the de scribed process are products of RAl Research Corporation, Hauppauge, New York, identified as 18ST12S and 16ST13S, the former being 18% styrenated and having two-thirds of the phenyl groups monosulfonated and the latter being 16% styrenated and having thirteen-sixteenths of the phenyl groups monosulfonated.
- 18% styrenation a solution of 17%% of styrene in methylene chloride is utilized and to obtain the 16% styrenation a solution of 16% of styrene in methylene chloride is employed.
- the membrane walls will normally be from 0.02 to 0.5 mm. thick, preferably from 0.1 to 0.5 mm. and most preferably 0.1 to 0.3 mm.
- the network filaments or fibers When mounted on a polytet rafluoroethylene, asbestos, titanium or other suitable network, for support, the network filaments or fibers will usually have a thickness of 0.01 to 0.5 mm., preferably 0.05 to 0.15 mm., corresponding to up to the thickness of the membrane. Often it will be preferable for the fibers to be less than half the film thickness but filament thicknesses greater than that of the film may also be successfully employed, e.g., 1.1 to 5 times the film thickness.
- the networks, screens or cloths have an area percentage of openings therein from about 8 to 80%, preferably 10 to and most preferably 30 to 70%. Generally the cross sections of the filaments will be circular but other shapes, such as ellipses, squares and rectangles, are also useful.
- the supporting network is preferably a screen or cloth and although it may be cemented to the membrane it is preferred that it be fused to it by high temperature, high pressure compression before hydrolysis of the copolymer. Then, the membrane-network composite can be clamped or otherwise fastened in place in a holder or support.
- the material of construction of the cell body may be conventional, including concrete or stressed concrete lined with mastics, rubbers, e.g., neoprene, polyvinylidene chloride, FEP, chlorendic acid based polyester, polypropylene, polyvinyl chloride, TFE or other suitable plastic or may be similarly lined boxes of other structural materials.
- Substantially selfsupporting structures such as rigid polyvinyl chloride, polyvinylidene chloride, polypropylene or phenol formaldehyde resins may be employed, preferably reinforced with moldedin fibers, cloths or webs of glass filaments, steel, nylon,
- the electrodes of the cell can be made of any electrically conductive material which will resist the attack of the various cell contents.
- the cathodes are made of graphite, iron, lead dioxide on graphite or titanium, steel or noble metal, such as platinum, iridium, ruthenium or rhodium.
- noble metals they may be deposited as surfaces on conductive substrates, e.g., copper, silver, aluminum, steel, iron.
- the anodes are also of materials or have surfaces of materials such as noble metals, noble metal alloys, noble metal oxides, noble metal oxides mixed with valve metal oxides, e.g., ruthenium oxide plus titanium dioxide, or mixtures thereof, on a substrate which is conductive.
- such surfaces are on or with a valve metal and connect to a conductive metal, such as those described.
- a conductive metal such as those described.
- the conductors for such materials may be aluminum, copper, silver, steel or iron, with copper being much preferred.
- a preferable dimensionally stable anode is ruthenium oxide-titanium dioxide mixture on a titanium substrate, connected to a copper conductor.
- the voltage drops from anodes to cathodes are usually in the range of about 2.3 to volts, although sometimes they are slightly more than 5 volts, e.g., up to 6 volts. Preferably, they are in the range of 3.5 to 4.5
- the current densities while they may be from 0.5
- amperes per square inch of electrode surface are preferably from 1 to 3 amperes/sq. in. and ideally about 2 amperes/sq. in.
- the voltage ranges are for perfectly aligned electrodes and it is understood that where such alignment is not exact, as in laboratory units, the voltages can be up to about 0.5 volt higher.
- the important advantages of the present invention is in the production of concentrated caustic, low in chloride concentration, without the need for dilute caustic being an end product of the method. Yet, this is done at a comparatively high efficiency due to the utilization of the three-compartment cell and the initial manufacture of dilute caustic in the buffer compartment thereof.
- the use of the buffer compartment and the presence of dilute caustic in it diminishes the pressure on caustic ions to penetrate into the anode compartment of that cell and thereby improves efficiency because less oxygen or other relatively useless product is manufactured in the anolyte than would be the case were more hydroxide to penetrate into it.
- the pressre of the caustic can also be diminished by feeding additional water to the compartment and making a weaker caustic therein, e.g., one of as little as 25 to 50 g./l. concentration.
- a weaker caustic e.g., one of as little as 25 to 50 g./l. concentration.
- the improved efficiency of this operation must be balanced against the employment of so weak a caustic as a feed to the catholyte of the two-compartment cell.
- the anolyte of both cells should be acidic so that it can react with any hydroxyl entering the anode compartment from the buffer zone, preventing oxygen formation.
- a pH in the ranges of 1 to 6 can be used, the range of l to 5 is preferred and 2 to 4 is best.
- the buffer solution and catholyte pHs are 14.
- the temperature of the electrolyte will be maintained at less than 105C., preferably being 20 to 95C., more preferably being 50 to 95C. and most preferably being about 65 to 95C. Electrolyte temperatures may be controlled by recirculation of portions thereof and by regulations of proportions of feeds to the various zones and the temperatures of such feeds.
- refrigeration or other cooling means or liquids may also be employed.
- feeds of diluting water to the buffer companment and dilute caustic to the catholyte compartment of the two-compartment cell and any recirculating anolyte employed may be cooled to about 10to 20C., preferably to about 10C., before admission to the compartment and recirculating electrolyte moving essentially intracompartmentally may also be cooled.
- cooling may be merely by exposure of the liquids to ambient conditions before they enter or reenter the cells.
- the high concentration caustic solution made is free of chloride or essentially free thereof, often containing as little as 0.1 to .10 g./l. and usually about one g./l. thereof, with the caustic concentration in the 250 to 400 or 250 to 450 g.'/l. range. Such caustic concentrations may be further increased by evaporation and comparatively little thermal energy is needed to raise them to 50%.
- a possible disadvantage of the present method the production of chlorate in the anolyte of the two-compartment" cell, is even convertible to an advantage, when that anolyte effluent is fed to chlorate cells.
- the chlorate may be separated from the recirculating anolyte and may be commercially utilized. I
- the present cells may be incorporated in large or small plants, thus producing usable caustic while making from 20 to 1,000 tons per day of chlorine or equivalent and in all cases efficiencies obtained can be such as to make the process economically desirable. It is highly preferred however, that the installation should be located near to and be used in conjunction with a pulp bleaching plant so that the chlorine and chlorate, if any of the latter salt is produced, may be used together with the concentrated caustic in wood pulp bleaching or in the production of bleaching agents, e.g., chlorine dioxide. Of course, the caustic and chlorine manufactured may also be marketed.
- EXAMPLE 1 The three-compartment and two-compartment cells of the Figure are employed, with the changes described herein, to produce chlorine, hydrogen and concentrated sodium hydroxide solution from an aqueous sodium chloride solution. As illustrated, for simplicity, a single three-compartment and a single twocompartment cell are employed but in actual practice the ratio of threecompartment cells to twocompartment cells will be about 1.5, with the feeds to the various cells and discharges from them often being through common lines.
- the cell walls are-of asbestos filled polypropylene or polypropylene or may be of steel lined with unplasticized polyvinyl chloride and in some instances, polypropylene.
- Polyesters such as chlorendic acid based polyesters, e.g., Hetron, made by Hooker Chemical Corp., may be used as a wall lining, too. Rubber or other synthetic plastic gaskets may act as seals between cell walls, covers and other parts.
- the electrodes are in contact with the membranes separating the buffer compartment from the electrode compartments of the three-compartment cell and such membranes are cation-active permselective membranes manufactured by E. I. DuPont de Nemours & Company, lnc. and sold as their XR-type membranes.
- the membranes are 7 mils thick, (about 0.2 mm.) and are joined to a backing or supporting network of polytetrafluoroethylene (Teflon) filaments of a diameter of about 0.1 mm., woven into a cloth which has an area percentage of openings therein of about 22%. They were initially flat and were fused onto the screen or cloth of Teflon by high temperature, high compression pressing, with some of the membrane portions actually flowing around the filaments during the fusion process to lock onto the cloth, without thickening the membrane between the cloth filaments.
- Teflon polytetrafluoroethylene
- the material of the XR-type permselective membrane is a hydrolyzed copolymer of a perfluorinated hydrocarbon and a fluorosulfonated perfluorovinyl ether.
- the electrodes are in contact with the buffer membranes, with the flatter sides of the membranes facing the contacting electrodes. In some experiments spacings of 0.01 to 5 mm. between the electrodes and the membranes are utilized and satisfactory results are obtained but the present arrangement, and the absence of spacings is preferred.
- the same membranes are employed in both the three-compartment and twocompartment cells.
- the buffer compartment is about 6 mm. wide and the electrodes are positioned against the membranes, making the interelectrode distance essentially the same.
- the volume ratios of the anode compartment buffer compartment cathode compartment are about 10:1:10 and the anode and cathode compartment of the two-compartment cell are of about the same volume, with the permselective membrane being centrally located and electrode gaps (from anode to cathode) being 1 to 10 mm.
- the anodes utilized are of a mixture of ruthenium and titanium oxides on titaniumcommunicated with current sources by titanium-clad copper members.
- the titanium base for the anode is titanium mesh, about 1 mm., in diameter and with about 50% open area, coated with a 1:3 ruthenium oxide, titanium oxide mixture-about 1 mm. thick.
- the cathodes are of a mild steel wire mesh, essentially 1 mm. in equivalent diameter, having about 35% open area, and are communicated with negative electrical sources or sinks by a copper conductor.
- the anode compartments of the cells are filled with a nearly saturated salt solution or brine of sodium chloride at about a concentration and the cathode and buffer compartment are filled with water, initially containing'a small quantity of salt or brine to improve conductivity.
- the current is turned on and the chlorine and hydrogen produced in the cells are taken off.
- Water is fed to the buffer compartment of the threecompartment cell to maintain the concentration of sodium hydroxide therein low and at the desired concentrations dilute and more concentrated sodium hydroxide solutions are removed from the buffer compartment and the cathode compartment, respectively, of the three-compartment cell.
- That taken off the buffer compartment is fed to the cathode compartment of the the sodium chloride content of the withdrawn anolyte is about 22% by weight and that of the returned anolyte from the resaturator is about 25%.
- a proportion of the recirculating electrolyte may bypass the resaturator.
- a similar recirculation and resaturation in the anolyte of the two-compartment cell is effected, utilizing the same resaturator and by valve adjustment the proportions of flows to each of the anolyte compartments of the three-compartment and twocompartment cells are regulated.
- separately circulating systems may be employed.
- Chlorine is produced at a current efficiency of about 96% and it contains essentially no free oxygen.
- the caustic efficiency of the threecompartment cell is about 90% and it produces 36 tons of sodium hydroxide per day at a concentration of 400 g./l. and 18 tons per day at a concentration of g./l.
- the more concentrated caustic contains only 0.5 g./l. of NaCl. It is sent to an evaporator and is raised to 50% concentration, although in some instances it is sold directly as 400 g./l. solution or is utilized in such form for woodpulp treatment.
- the gap between the anode and cathode is approximately 2 mm.
- the chloride solution feeds are the same as for the threecompartment cell and in addition to the caustic charge to the cathode compartment and thefeed solution to the anode compartment, sometimes a water feed is sent to the cathode compartment to regulate the concentration of the product thereof.
- the eight cells produce a total of 42 tons of sodium hydroxide per day of a concentration of 400 g./l. and a sodium chloride concentration of 0.8 g./l.
- the total hydroxide production for the 20 cells is 78 tons of sodium hydroxide per day, which corresponds to a total plant caustic efficiency of about 78%.
- the three-compartment cells operate at a caustic efficiency of about 85-90% and the twocompartment cells operate at about 60% caustic efficiency.
- the chlorine produced in the two-compartment cells may be kept separate from that of the three-compartment cells because of its oxygen or impurity content being more than would have been the case if it was acidified. However, it contains less than 6% of oxyen.
- hydrochloric acid is added to the anolyte of the twocompartment cells in sufficient quantity to neutralize the migrating caustic the chlorine from the cell can be as pure as that from a threecompartment cell.
- the products obtained are used in pulping and in pulp bleaching operations, especially in the treatment of groundwood pulps.
- the caustic and chlorine are reacted to form bleaching agents, such as hypochlorite and chlorate, the latter of which may be subsequently treated to produce chlorine dioxide for pulp bleaching.
- the thicknesses of the membranes are increased to to 14 mils, at which caustic efficiencies increase but voltage drops are also greater.
- the membranes of greater thicknesses are operative it is preferred to employ the 7 mil membranes in these reactions.
- the membranes thickness is decreased to 4 mils the process is satisfactory but caustic efficiency is diminished somewhat.
- Example 2 The process of Example 1 is repeated, employing 10 mil membranes of membrane materials identified as l8STl2S and 16ST13S, respectively, made by RAI Research Corporation, in replacement of the hydrolyzed copolymer of tetrafluoroethylene and sulfonated perfluorovinyl ether.
- the former of the RAI products is a sulfostyrenated FEP in which the FEP is 18% styrenated and has two-thirds of the phenyl groups thereof monosulfonated, and the latter is 16% styrenated and has thirteen-sixteenths of the phenyl groups monosulfonated.
- the membranes stand up better than other available cation-active permselective membranes but not as well as the membranes of Example 1.
- their characteristics e.g., physical appearances, uniformity, voltage drop, are better than other cation-active permselective membrane materials available (except the hydrolyzed copolymers of perfluorinated hydrocarbons and fluorosulfonated perfluorovinyl ethers) but especially in the anode compartment where chlorine attacks the membrane lengthening of operating life is desirable.
- the RAI membranes are decidedly better in operation than comparable commercial products, except for those of the MX type.
- the operating temperature is changed to 80C. and although efficiencies are somewhat lower the reactions are satisfactorily operative. Similar good results are also obtained when the surface of the cathode is changed to platinum or graphite and the surface of the anode is changed to platinum or ruthenium oxide (on titanium).
- the concentrated caustic and chlorine of this example are used to make sodium chlorate and the 400 g./l. caustic, without further concentration, is employed for the pulping of groundwood.
- Example 3 The experiment of Example I is repeated, using a single three-compartment cell and a single twocompanment cell and feeding two-thirds of the dilute caustic production of the three-compartment to the cathode compartment of the two-compartment cell. Otherwise, the conditions obtaining are the same and the results thereof are the same although production of concentrated caustic falls off accordingly and some dilute caustic remains to be disposed of, (it is used in the pulping of groundwood).
- the high concentration caustic solution produced contains from 375 to 425 g./l. of sodium hydroxide and the feed to the two-compartment from the threecompartment cell is from to g./l. sodium hydroxide.
- the continuous processes described are changed to batch operations and while efficiencies drop, the processes are operative and produce the same high concentration caustics of good purities.
- a method for electrolytically manufacturing a concentrated hydroxide solution containing over 250 but less than 450 g./l. of sodium hydroxide or equivalent hydroxide which comprises making concentrated and dilute aqueous hydroxide solutions simultaneously by electrolyzing an aqueous solution containing halide ions in an electrolytic cell having at least three compartments therein, an anode, a cathode, at least two cation-active permselective membranes of a polymeric material selected from the group consisting of a hydrolyzed copolymer of a perfluorinated hydrocarbon and a fluorosulfonated perfluorovinyl ether and a sulfostyrenated perfluorinated ethylene propylene polymer, defining anode and cathode side walls of a buffer compartment or compartments between anode and cathode compartments, and such walls, with walls thereabout, defining anode and cathode compartments, while adding water to the buffer compartment at
- a two-compartment electrolytic cell having anode and cathode compartments separated by a cation-active permselective membrane of a polymeric material selected from the group consisting of a hydrolyzed copolymer of a perfluorinated hydrocarbon and a fluorosulfonated perfluorovinyl ether, and a sulfostyrenated perfluorinated ethylene propylene polymer, in which cell, in the anode compartment thereof, an aqueous solution containing halide ions is electrolyzed, and withdrawing from the catholyte compartment of the two-compartment cell concentrated hydroxide solution containing more than 250 but less than 450 g./l. of sodium hydroxide or equivalent, so that the cathode compartment efficiency of the
- the electrolytic cells are three-compartment and twocompartment cells
- the concentration of sodium chloride in the anode compartments of the three-compartment and two-compartment cells is from about 200 to 320 g./l.
- the pH of the anolytes in both cells is about 1 to 5 and the temperatures of the anolytes, catholytes and buffer compartment solution are less than 105C.
- permselective membranes are mounted on networks of a material selected from the group consisting of polytetrafluoroethylene, asbestos, perfluorinated ethylene propylene polymer, polypropylene, titanium, tantalum, niobium and noble metals, which networks have area percentages of openings therein from about 8 to 80%, the temperatures of the anolytes, catholytes and buffer compartment solution are in the range of to 95C, the surfaces of the cathodes are of a material selected from the group consisting of platinum, iridium, ruthenium, rhodium, graphite, iron and steel, the surfaces of the anodes are of a material selected from the group consisting of noble metals, noble metal alloys, noble metal oxides, mixtures of noble metal oxides with valve metal oxides, or mixture thereof, on a valve metal, the voltage is from about 2.3 to 6 volts and the current density is from about 0.5 to 4 amperes per square inch of
- networks are screens of cloths of polytetrafluoroethylene filaments having a thickness of 0.1 to 0.3 mm.
- the membrane walls are from 0.1 to 0.3 mm. thick
- the polytetrafluoroethylene filament thickness is less than or equal to that of the membrane walls
- thecopolymer equivalent weight is from about 1,100 to 1,400
- the cathodes are of steel
- the anodes are of ruthenium oxide on titanium
- the aqueous sodium chloride solution electrolytes are at a concentration of about 250 to 320 g./l.
- the pH of the anolyte is from to 4 and the temperatures of the anolytes, catholytes and buffer compartment solution are from 65 to 95C.
- the two'compartment cells operating at about 60% caustic efficiency or more, with the solution removed from the cathode compartment of both cells being at about 400 g./l. sodium hydroxide, the proportion of three-compartment cells to twocompartment cells is about 1.5 and the buffer compartment solution withdrawn from three threecompartment cells is fed to the catholytes of two twocompartment cells.
- aqueous solution of sodium hydroxide withdarwn from the buffer compartment of the three-compartment cell is at a concentration of about to 150 g./l.
- concentrations of the catholytes withdrawn from the threecompartment and two-compartment cells are about 375 to 425 g./l. and the caustic efficiency of the combined process is over 75%.
- a method according to claim 3 wherein a plurality of three-compartment and two-compartment cells is employed, the three-compartment cells operating at about 90% caustic efficiency or more and producing buffer compartment solution containing about g./l. sodium hydroxide and the two-compartment cells operating at about 60% caustic efficiency or more, with the solution removed from the cathode compartments of both cells being at about 400 g./l. sodium hydroxide, the proportion of three-compartment cells to twocompartment cells is about 1.5 and the buffer compartment solution withdrawn from three threecompartment cells is fed to the catholytes of two two compartment cells.
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- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Electrochemistry (AREA)
- Materials Engineering (AREA)
- Metallurgy (AREA)
- Organic Chemistry (AREA)
- Inorganic Chemistry (AREA)
- Electrolytic Production Of Non-Metals, Compounds, Apparatuses Therefor (AREA)
- Separation Using Semi-Permeable Membranes (AREA)
Priority Applications (12)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US411619A US3899403A (en) | 1973-11-01 | 1973-11-01 | Electrolytic method of making concentrated hydroxide solutions by sequential use of 3-compartment and 2-compartment electrolytic cells having separating compartment walls of particular cation-active permselective membranes |
AU74529/74A AU7452974A (en) | 1973-11-01 | 1974-10-21 | Concentrated hydroxide solution |
NO743912A NO743912L (xx) | 1973-11-01 | 1974-10-30 | |
FR7436301A FR2249972A1 (xx) | 1973-11-01 | 1974-10-30 | |
AR256341A AR209270A1 (es) | 1973-11-01 | 1974-10-30 | Conjunto de celdas electroliticas |
NL7414203A NL7414203A (nl) | 1973-11-01 | 1974-10-30 | Werkwijze voor de elektrolytische bereiding van geconcentreerde hydroxydeoplossingen. |
FI3193/74A FI319374A (xx) | 1973-11-01 | 1974-10-31 | |
JP49126516A JPS5075195A (xx) | 1973-11-01 | 1974-10-31 | |
DE19742451847 DE2451847A1 (de) | 1973-11-01 | 1974-10-31 | Verfahren zur elektrolytischen herstellung von metallhydroxidloesungen |
SE7413728A SE7413728L (xx) | 1973-11-01 | 1974-10-31 | |
BR9139/74A BR7409139D0 (pt) | 1973-11-01 | 1974-10-31 | Processo para producao de solucoes concentradas de um hidroxidos pelo uso consecutivo de celulas eletroliticas de 3 compartimentos e 2 compartimentos tendo paredes divisorias dos compartimentos de membranas permo-seletivas cationicamente ativas |
IT29063/74A IT1025403B (it) | 1973-11-01 | 1974-10-31 | Procedimento per fabbricare soluzioni concentrate di idrado sodico mediante impiego successivo di celle elttrolitiche a tre e a due compartimenti aventi pareti di separazione di particolari membrane permoselettive cation attive |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US411619A US3899403A (en) | 1973-11-01 | 1973-11-01 | Electrolytic method of making concentrated hydroxide solutions by sequential use of 3-compartment and 2-compartment electrolytic cells having separating compartment walls of particular cation-active permselective membranes |
Publications (1)
Publication Number | Publication Date |
---|---|
US3899403A true US3899403A (en) | 1975-08-12 |
Family
ID=23629662
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US411619A Expired - Lifetime US3899403A (en) | 1973-11-01 | 1973-11-01 | Electrolytic method of making concentrated hydroxide solutions by sequential use of 3-compartment and 2-compartment electrolytic cells having separating compartment walls of particular cation-active permselective membranes |
Country Status (12)
Country | Link |
---|---|
US (1) | US3899403A (xx) |
JP (1) | JPS5075195A (xx) |
AR (1) | AR209270A1 (xx) |
AU (1) | AU7452974A (xx) |
BR (1) | BR7409139D0 (xx) |
DE (1) | DE2451847A1 (xx) |
FI (1) | FI319374A (xx) |
FR (1) | FR2249972A1 (xx) |
IT (1) | IT1025403B (xx) |
NL (1) | NL7414203A (xx) |
NO (1) | NO743912L (xx) |
SE (1) | SE7413728L (xx) |
Cited By (23)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4057474A (en) * | 1976-06-25 | 1977-11-08 | Allied Chemical Corporation | Electrolytic production of alkali metal hydroxide |
US4076603A (en) * | 1977-04-07 | 1978-02-28 | Kaiser Aluminum & Chemical Corporation | Caustic and chlorine production process |
US4080270A (en) * | 1975-01-22 | 1978-03-21 | Diamond Shamrock Corporation | Production of alkali metal carbonates in a membrane cell |
US4093531A (en) * | 1975-12-29 | 1978-06-06 | Diamond Shamrock Corporation | Apparatus for concentration and purification of a cell liquor in an electrolytic cell |
US4147599A (en) * | 1977-07-19 | 1979-04-03 | Diamond Shamrock Corporation | Production of alkali metal carbonates in a cell having a carboxyl membrane |
US4147600A (en) * | 1978-01-06 | 1979-04-03 | Hooker Chemicals & Plastics Corp. | Electrolytic method of producing concentrated hydroxide solutions |
US4212712A (en) * | 1975-11-19 | 1980-07-15 | Kureha Kagaku Kogyo Kabushiki Kaisha | Process for the electrolytic treatment of alkali metal halide solution using ion exchange membranes |
US4938852A (en) * | 1987-07-17 | 1990-07-03 | Rhone-Poulenc Chimie | Recovery of europium (II) values by electrolysis |
US20020179435A1 (en) * | 2001-06-04 | 2002-12-05 | Maddan Orville Lee | Apparatus and method for producing magnesium from seawater |
CN103628085A (zh) * | 2013-11-22 | 2014-03-12 | 新汶矿业集团有限责任公司泰山盐化工分公司 | 氯碱生产中水资源循环利用方法 |
US20140311897A1 (en) * | 2011-12-14 | 2014-10-23 | Techwin Co., Ltd. | Highly efficient sodium hypochlorite generation apparatus capable of decreasing disinfection by-products |
CN105063655A (zh) * | 2015-08-12 | 2015-11-18 | 江阴安凯特电化学设备有限公司 | 生产亚氨基二乙酸的方法 |
US9644278B2 (en) * | 2015-03-13 | 2017-05-09 | Barbara Jean Manojlovich | Recycling hydrogen generator |
US10036094B2 (en) * | 2013-10-23 | 2018-07-31 | Nemaska Lithium Inc. | Processes and systems for preparing lithium hydroxide |
US10544512B2 (en) | 2014-02-24 | 2020-01-28 | Nemaska Lithium Inc. | Methods for treating lithium-containing materials |
US10633748B2 (en) | 2012-04-23 | 2020-04-28 | Nemaska Lithium Inc. | Processes for preparing lithium hydroxide |
US10800663B2 (en) | 2012-05-30 | 2020-10-13 | Nemaska Lithium Inc. | Processes for preparing lithium carbonate |
US10900132B2 (en) | 2017-01-26 | 2021-01-26 | Diversey, Inc. | Neutralization in electro-chemical activation systems |
US11078583B2 (en) | 2013-03-15 | 2021-08-03 | Nemaska Lithium Inc. | Processes for preparing lithium hydroxide |
US11083978B2 (en) | 2016-08-26 | 2021-08-10 | Nemaska Lithium Inc. | Processes for treating aqueous compositions comprising lithium sulfate and sulfuric acid |
US11142466B2 (en) | 2017-11-22 | 2021-10-12 | Nemaska Lithium Inc. | Processes for preparing hydroxides and oxides of various metals and derivatives thereof |
US11326261B2 (en) | 2016-05-17 | 2022-05-10 | Diversey, Inc. | Alkaline and chlorine solutions produced using electro-chemical activation |
US11697861B2 (en) | 2013-10-23 | 2023-07-11 | Nemaska Lithium Inc. | Processes for preparing lithium carbonate |
Families Citing this family (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPS597795B2 (ja) * | 1975-04-17 | 1984-02-21 | 株式会社トクヤマ | 電解用陰極鑵 |
FR2355926A1 (fr) * | 1975-11-21 | 1978-01-20 | Rhone Poulenc Ind | Diaphragme selectif d'electrolyse |
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US3222267A (en) * | 1961-05-05 | 1965-12-07 | Ionics | Process and apparatus for electrolyzing salt solutions |
US3282875A (en) * | 1964-07-22 | 1966-11-01 | Du Pont | Fluorocarbon vinyl ether polymers |
US3341366A (en) * | 1964-08-19 | 1967-09-12 | Gen Electric | Sulfonated polymers of alpha, beta, beta-trifluorostyrene, with applications to structures and cells |
US3496077A (en) * | 1967-12-18 | 1970-02-17 | Hal B H Cooper | Electrolyzing of salt solutions |
US3718551A (en) * | 1968-10-14 | 1973-02-27 | Ppg Industries Inc | Ruthenium coated titanium electrode |
US3773634A (en) * | 1972-03-09 | 1973-11-20 | Diamond Shamrock Corp | Control of an olyte-catholyte concentrations in membrane cells |
-
1973
- 1973-11-01 US US411619A patent/US3899403A/en not_active Expired - Lifetime
-
1974
- 1974-10-21 AU AU74529/74A patent/AU7452974A/en not_active Expired
- 1974-10-30 NO NO743912A patent/NO743912L/no unknown
- 1974-10-30 FR FR7436301A patent/FR2249972A1/fr not_active Withdrawn
- 1974-10-30 NL NL7414203A patent/NL7414203A/xx unknown
- 1974-10-30 AR AR256341A patent/AR209270A1/es active
- 1974-10-31 BR BR9139/74A patent/BR7409139D0/pt unknown
- 1974-10-31 FI FI3193/74A patent/FI319374A/fi unknown
- 1974-10-31 DE DE19742451847 patent/DE2451847A1/de active Pending
- 1974-10-31 IT IT29063/74A patent/IT1025403B/it active
- 1974-10-31 SE SE7413728A patent/SE7413728L/ not_active Application Discontinuation
- 1974-10-31 JP JP49126516A patent/JPS5075195A/ja active Pending
Patent Citations (7)
Publication number | Priority date | Publication date | Assignee | Title |
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US2967807A (en) * | 1952-01-23 | 1961-01-10 | Hooker Chemical Corp | Electrolytic decomposition of sodium chloride |
US3222267A (en) * | 1961-05-05 | 1965-12-07 | Ionics | Process and apparatus for electrolyzing salt solutions |
US3282875A (en) * | 1964-07-22 | 1966-11-01 | Du Pont | Fluorocarbon vinyl ether polymers |
US3341366A (en) * | 1964-08-19 | 1967-09-12 | Gen Electric | Sulfonated polymers of alpha, beta, beta-trifluorostyrene, with applications to structures and cells |
US3496077A (en) * | 1967-12-18 | 1970-02-17 | Hal B H Cooper | Electrolyzing of salt solutions |
US3718551A (en) * | 1968-10-14 | 1973-02-27 | Ppg Industries Inc | Ruthenium coated titanium electrode |
US3773634A (en) * | 1972-03-09 | 1973-11-20 | Diamond Shamrock Corp | Control of an olyte-catholyte concentrations in membrane cells |
Cited By (32)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4080270A (en) * | 1975-01-22 | 1978-03-21 | Diamond Shamrock Corporation | Production of alkali metal carbonates in a membrane cell |
US4212712A (en) * | 1975-11-19 | 1980-07-15 | Kureha Kagaku Kogyo Kabushiki Kaisha | Process for the electrolytic treatment of alkali metal halide solution using ion exchange membranes |
US4093531A (en) * | 1975-12-29 | 1978-06-06 | Diamond Shamrock Corporation | Apparatus for concentration and purification of a cell liquor in an electrolytic cell |
US4057474A (en) * | 1976-06-25 | 1977-11-08 | Allied Chemical Corporation | Electrolytic production of alkali metal hydroxide |
US4076603A (en) * | 1977-04-07 | 1978-02-28 | Kaiser Aluminum & Chemical Corporation | Caustic and chlorine production process |
US4147599A (en) * | 1977-07-19 | 1979-04-03 | Diamond Shamrock Corporation | Production of alkali metal carbonates in a cell having a carboxyl membrane |
US4147600A (en) * | 1978-01-06 | 1979-04-03 | Hooker Chemicals & Plastics Corp. | Electrolytic method of producing concentrated hydroxide solutions |
US4938852A (en) * | 1987-07-17 | 1990-07-03 | Rhone-Poulenc Chimie | Recovery of europium (II) values by electrolysis |
US20020179435A1 (en) * | 2001-06-04 | 2002-12-05 | Maddan Orville Lee | Apparatus and method for producing magnesium from seawater |
US20140311897A1 (en) * | 2011-12-14 | 2014-10-23 | Techwin Co., Ltd. | Highly efficient sodium hypochlorite generation apparatus capable of decreasing disinfection by-products |
US9650721B2 (en) * | 2011-12-14 | 2017-05-16 | Techwin Co., Ltd. | Highly efficient sodium hypochlorite generation apparatus capable of decreasing disinfection by-products |
US10633748B2 (en) | 2012-04-23 | 2020-04-28 | Nemaska Lithium Inc. | Processes for preparing lithium hydroxide |
US11634336B2 (en) | 2012-05-30 | 2023-04-25 | Nemaska Lithium Inc. | Processes for preparing lithium carbonate |
US11254582B2 (en) | 2012-05-30 | 2022-02-22 | Nemaska Lithium Inc. | Processes for preparing lithium carbonate |
US10800663B2 (en) | 2012-05-30 | 2020-10-13 | Nemaska Lithium Inc. | Processes for preparing lithium carbonate |
US11078583B2 (en) | 2013-03-15 | 2021-08-03 | Nemaska Lithium Inc. | Processes for preparing lithium hydroxide |
US10036094B2 (en) * | 2013-10-23 | 2018-07-31 | Nemaska Lithium Inc. | Processes and systems for preparing lithium hydroxide |
US11697861B2 (en) | 2013-10-23 | 2023-07-11 | Nemaska Lithium Inc. | Processes for preparing lithium carbonate |
CN103628085B (zh) * | 2013-11-22 | 2016-10-05 | 新汶矿业集团有限责任公司泰山盐化工分公司 | 氯碱生产中水资源循环利用方法 |
CN103628085A (zh) * | 2013-11-22 | 2014-03-12 | 新汶矿业集团有限责任公司泰山盐化工分公司 | 氯碱生产中水资源循环利用方法 |
US10544512B2 (en) | 2014-02-24 | 2020-01-28 | Nemaska Lithium Inc. | Methods for treating lithium-containing materials |
US11085121B2 (en) | 2014-02-24 | 2021-08-10 | Nemaska Lithium Inc. | Methods for treating lithium-containing materials |
US11519081B2 (en) | 2014-02-24 | 2022-12-06 | Nemaska Lithium Inc. | Methods for treating lithium-containing materials |
US9644278B2 (en) * | 2015-03-13 | 2017-05-09 | Barbara Jean Manojlovich | Recycling hydrogen generator |
CN105063655B (zh) * | 2015-08-12 | 2017-06-06 | 江苏安凯特科技股份有限公司 | 生产亚氨基二乙酸的方法 |
CN105063655A (zh) * | 2015-08-12 | 2015-11-18 | 江阴安凯特电化学设备有限公司 | 生产亚氨基二乙酸的方法 |
US11326261B2 (en) | 2016-05-17 | 2022-05-10 | Diversey, Inc. | Alkaline and chlorine solutions produced using electro-chemical activation |
US11083978B2 (en) | 2016-08-26 | 2021-08-10 | Nemaska Lithium Inc. | Processes for treating aqueous compositions comprising lithium sulfate and sulfuric acid |
US10900132B2 (en) | 2017-01-26 | 2021-01-26 | Diversey, Inc. | Neutralization in electro-chemical activation systems |
US11142466B2 (en) | 2017-11-22 | 2021-10-12 | Nemaska Lithium Inc. | Processes for preparing hydroxides and oxides of various metals and derivatives thereof |
US11542175B2 (en) | 2017-11-22 | 2023-01-03 | Nemaska Lithium Inc. | Processes for preparing hydroxides and oxides of various metals and derivatives thereof |
US12006231B2 (en) | 2017-11-22 | 2024-06-11 | Nemaska Lithium Inc. | Processes for preparing hydroxides and oxides of various metals and derivatives thereof |
Also Published As
Publication number | Publication date |
---|---|
FR2249972A1 (xx) | 1975-05-30 |
NL7414203A (nl) | 1975-05-06 |
FI319374A (xx) | 1975-05-02 |
NO743912L (xx) | 1975-05-26 |
BR7409139D0 (pt) | 1975-08-26 |
IT1025403B (it) | 1978-08-10 |
AR209270A1 (es) | 1977-04-15 |
SE7413728L (xx) | 1975-05-02 |
AU7452974A (en) | 1976-04-29 |
DE2451847A1 (de) | 1975-05-07 |
JPS5075195A (xx) | 1975-06-20 |
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Owner name: OCCIDENTAL CHEMICAL CORPORATION Free format text: CHANGE OF NAME;ASSIGNOR:HOOKER CHEMICALS & PLASTICS CORP.;REEL/FRAME:004109/0487 Effective date: 19820330 |
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Owner name: OXYTECH SYSTEMS, INC., CHARDON, OH A CORP. OF DE Free format text: ASSIGNMENT OF ASSIGNORS INTEREST.;ASSIGNOR:OCCIDENTAL CHEMICAL CORPORATION, A NY CORP;REEL/FRAME:004747/0454 Effective date: 19870219 Owner name: OXYTECH SYSTEMS, INC., OHIO Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNOR:OCCIDENTAL CHEMICAL CORPORATION, A NY CORP;REEL/FRAME:004747/0454 Effective date: 19870219 |