WO1986005215A1 - Method for the electrochemical oxidation of sulphuric acid chromium iii solutions into chromium vi solutions - Google Patents
Method for the electrochemical oxidation of sulphuric acid chromium iii solutions into chromium vi solutions Download PDFInfo
- Publication number
- WO1986005215A1 WO1986005215A1 PCT/AT1986/000016 AT8600016W WO8605215A1 WO 1986005215 A1 WO1986005215 A1 WO 1986005215A1 AT 8600016 W AT8600016 W AT 8600016W WO 8605215 A1 WO8605215 A1 WO 8605215A1
- Authority
- WO
- WIPO (PCT)
- Prior art keywords
- chromium
- nitric acid
- solutions
- oxygen
- sulphuric acid
- Prior art date
Links
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
- C25B1/00—Electrolytic production of inorganic compounds or non-metals
Definitions
- the invention relates to a process for the electrochemical oxidation of sulfuric acid chromium III solutions to chromium VI solutions.
- nitric acid-containing, sulfuric, chromium-III solutions such as are produced in the oxidative purification of flue gases, is very difficult. If nitric acid remains in the electrolyte when the oxidant is worked up, up to 30% ammonium ions are formed on the cathode in the presence of chromium III ions, in addition to the hydrogen. The discharge of these ammonium salts is only possible by complex processes.
- the cell voltages that can be achieved in practice in this arrangement are between 4.8 and 6.4 volts and can be increased even further due to the poorer conductivity of chrome-plated cathodes.
- the object of the invention is to provide a process of the type mentioned at the outset which on the one hand avoids the disadvantages of the known processes and on the other hand the electricity costs for the electrolysis are lower.
- the process according to the invention is characterized in that the electrolyte contains nitric acid, sulfuric acid and chromium, the nitric acid being Redox transmitter is used for the oxygen electrode serving as the cathode and that the nitric acid is regenerated by flushing oxygen or air into the electrolyte in the cathode compartment.
- the method according to the invention allows a considerable reduction in the electricity costs in electrolysis.
- the most positive cathode fraction is the cathodic oxygen reduction.
- the reduction of oxygen in acidic solutions is, however, kinetically strongly inhibited.
- Usable oxygen electrodes require either expensive catalysts based on precious metals or suitable redox carriers in an acidic environment.
- the reduced species of the redox transmitter must have such a high reactivity that it can be oxidized again by the oxygen dissolved in the electrolyte.
- the reduction of nitric acid was chosen as the cathode reaction for the process according to the invention, since its reversible potential of +940 mV is close to that of the oxygen electrode.
- the cell voltages that can be achieved under these conditions are between 0.9 volts and approximately 2 volts. This means that the electricity costs for electrolysis can be reduced to about 1/3.
- the electrolysis is preferably operated with an electrolyte composition of 20 g / 1 to 300 g / 1 H2SO4, 20 g / 1 to 200 g / 1 HNO3 and 20 g / 1 to 30 g / 1 chromium.
- electrodes with high oxygen overvoltage such as, for. B. lead dioxide, manganese dioxide, tin dioxide and / or combinations thereof.
- the electrolytic cell consists of the usual arrangement of a plurality of anode and cathode spaces which are separated by diaphragms and are connected in series, anodes and cathodes working as bipolar electrodes.
- the electrolyte is supplied to the individual cathode compartments and then to the anode compartments via appropriate supply lines and is drawn off via a collecting line. Air and / or oxygen is blown in, for example, through perforated tubes which are arranged in the bottom of the cathode spaces.
- Either porous gas diffusion electrodes made of activated carbon or graphite or shaking electrodes made of the same material are used as cathodes. That consumes residual gas, with traces of nitrogen oxides, which can arise as intermediates in the cathode reaction and are entrained with the gas flow, is returned to the oxidative flue gas scrubbing.
Landscapes
- Chemical & Material Sciences (AREA)
- Inorganic Chemistry (AREA)
- Engineering & Computer Science (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Electrochemistry (AREA)
- Materials Engineering (AREA)
- Metallurgy (AREA)
- Organic Chemistry (AREA)
- Electrolytic Production Of Non-Metals, Compounds, Apparatuses Therefor (AREA)
- Treating Waste Gases (AREA)
- Water Treatment By Electricity Or Magnetism (AREA)
Description
Claims
Priority Applications (3)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
HU863023A HU201361B (en) | 1985-02-27 | 1986-02-27 | Process for electrochemical oxidating cr(ili)-solutions into cr(iv)-solutions |
DE8686901730T DE3664341D1 (en) | 1985-02-27 | 1986-02-27 | Method for the electrochemical oxidation of sulphuric acid chromium iii solutions into chromium vi solutions |
FI873678A FI80075C (fi) | 1985-02-27 | 1987-08-25 | Foerfarande foer elektrokemisk oxidation av svavelsyrahaltiga krom(iii)loesningar till krom (vi) loesningar. |
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
AT0057785A AT382894B (de) | 1985-02-27 | 1985-02-27 | Verfahren zur elektrochemischen oxidation von schwefelsauren chrom-iii-loesungen zu chrom-vil¯sungen |
ATA577/85 | 1985-02-27 |
Publications (1)
Publication Number | Publication Date |
---|---|
WO1986005215A1 true WO1986005215A1 (en) | 1986-09-12 |
Family
ID=3494262
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
PCT/AT1986/000016 WO1986005215A1 (en) | 1985-02-27 | 1986-02-27 | Method for the electrochemical oxidation of sulphuric acid chromium iii solutions into chromium vi solutions |
Country Status (11)
Country | Link |
---|---|
US (1) | US4859294A (de) |
EP (1) | EP0245279B1 (de) |
JP (1) | JPS62501979A (de) |
AT (1) | AT382894B (de) |
AU (1) | AU5580786A (de) |
BG (1) | BG80794A (de) |
DD (1) | DD243300A5 (de) |
DE (1) | DE3664341D1 (de) |
FI (1) | FI80075C (de) |
HU (1) | HU201361B (de) |
WO (1) | WO1986005215A1 (de) |
Cited By (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
EP0436146A1 (de) * | 1989-12-12 | 1991-07-10 | Hoechst Aktiengesellschaft | Verfahren zur elektrochemischen Regenerierung von ChromschwefelsÀ¤ure |
US6468414B1 (en) | 2001-02-16 | 2002-10-22 | Hydro-Quebec | Method of purification of a redox mediator before electrolytic regeneration thereof |
CN111094629A (zh) * | 2017-09-08 | 2020-05-01 | 冰岛大学 | 使用过渡金属氧化物催化剂电解生产氨 |
Families Citing this family (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
GB2399349A (en) * | 2003-03-13 | 2004-09-15 | Kurion Technologies Ltd | Regeneration of chromic acid etching and pickling baths |
JP6206382B2 (ja) * | 2014-11-28 | 2017-10-04 | 住友金属鉱山株式会社 | 水酸化インジウム粉の製造方法 |
Citations (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
FR2219806A1 (en) * | 1973-03-02 | 1974-09-27 | Basf Ag | Diaphragm cell for chromic-sulphuric acid prodn. - with membrane near cathode and high anode-cathode surface ratio |
US4006067A (en) * | 1973-03-05 | 1977-02-01 | Gussack Mark C | Oxidation-reduction process |
Family Cites Families (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
DE103860C (de) * | ||||
US1739107A (en) * | 1925-11-05 | 1929-12-10 | Marvin J Udy | Process of making chromic acid |
US4273628A (en) * | 1979-05-29 | 1981-06-16 | Diamond Shamrock Corp. | Production of chromic acid using two-compartment and three-compartment cells |
-
1985
- 1985-02-27 AT AT0057785A patent/AT382894B/de not_active IP Right Cessation
-
1986
- 1986-02-26 DD DD86287365A patent/DD243300A5/de unknown
- 1986-02-27 US US07/085,677 patent/US4859294A/en not_active Expired - Fee Related
- 1986-02-27 HU HU863023A patent/HU201361B/hu not_active IP Right Cessation
- 1986-02-27 DE DE8686901730T patent/DE3664341D1/de not_active Expired
- 1986-02-27 EP EP86901730A patent/EP0245279B1/de not_active Expired
- 1986-02-27 JP JP61501546A patent/JPS62501979A/ja active Pending
- 1986-02-27 WO PCT/AT1986/000016 patent/WO1986005215A1/de active IP Right Grant
- 1986-02-27 AU AU55807/86A patent/AU5580786A/en not_active Abandoned
-
1987
- 1987-07-30 BG BG080794A patent/BG80794A/bg unknown
- 1987-08-25 FI FI873678A patent/FI80075C/fi not_active IP Right Cessation
Patent Citations (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
FR2219806A1 (en) * | 1973-03-02 | 1974-09-27 | Basf Ag | Diaphragm cell for chromic-sulphuric acid prodn. - with membrane near cathode and high anode-cathode surface ratio |
US4006067A (en) * | 1973-03-05 | 1977-02-01 | Gussack Mark C | Oxidation-reduction process |
Non-Patent Citations (1)
Title |
---|
CHEMICAL ABSTRACTS, Volume 90, No. 24, 11 June 1979, Columbus Ohio (US) see page 531, column 1, Abstract 194736w & SU, A, 583202 (Letskikh) 5 December 1977 * |
Cited By (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
EP0436146A1 (de) * | 1989-12-12 | 1991-07-10 | Hoechst Aktiengesellschaft | Verfahren zur elektrochemischen Regenerierung von ChromschwefelsÀ¤ure |
US6468414B1 (en) | 2001-02-16 | 2002-10-22 | Hydro-Quebec | Method of purification of a redox mediator before electrolytic regeneration thereof |
CN111094629A (zh) * | 2017-09-08 | 2020-05-01 | 冰岛大学 | 使用过渡金属氧化物催化剂电解生产氨 |
Also Published As
Publication number | Publication date |
---|---|
US4859294A (en) | 1989-08-22 |
ATA57785A (de) | 1986-09-15 |
HU201361B (en) | 1990-10-28 |
JPS62501979A (ja) | 1987-08-06 |
HUT46081A (en) | 1988-09-28 |
EP0245279B1 (de) | 1989-07-12 |
BG80794A (bg) | 1993-12-24 |
FI873678A0 (fi) | 1987-08-25 |
DE3664341D1 (en) | 1989-08-17 |
AT382894B (de) | 1987-04-27 |
FI873678A (fi) | 1987-08-25 |
AU5580786A (en) | 1986-09-24 |
DD243300A5 (de) | 1987-02-25 |
FI80075C (fi) | 1990-04-10 |
FI80075B (fi) | 1989-12-29 |
EP0245279A1 (de) | 1987-11-19 |
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