GB2344340A - Treating acid contaminated with fission products - Google Patents
Treating acid contaminated with fission products Download PDFInfo
- Publication number
- GB2344340A GB2344340A GB9926831A GB9926831A GB2344340A GB 2344340 A GB2344340 A GB 2344340A GB 9926831 A GB9926831 A GB 9926831A GB 9926831 A GB9926831 A GB 9926831A GB 2344340 A GB2344340 A GB 2344340A
- Authority
- GB
- United Kingdom
- Prior art keywords
- acid
- process according
- base
- feedstock
- electrodialysis
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Withdrawn
Links
- 239000002253 acid Substances 0.000 title claims abstract description 38
- 230000004992 fission Effects 0.000 title claims abstract description 14
- 238000000034 method Methods 0.000 claims abstract description 40
- 239000012528 membrane Substances 0.000 claims abstract description 15
- 238000000909 electrodialysis Methods 0.000 claims abstract description 13
- 229910052792 caesium Inorganic materials 0.000 claims abstract description 11
- 230000002285 radioactive effect Effects 0.000 claims abstract description 7
- 238000004064 recycling Methods 0.000 claims abstract description 6
- 238000005202 decontamination Methods 0.000 claims abstract description 5
- 230000003472 neutralizing effect Effects 0.000 claims abstract description 5
- 229910000000 metal hydroxide Inorganic materials 0.000 claims abstract description 4
- 150000004692 metal hydroxides Chemical class 0.000 claims abstract description 4
- VEXZGXHMUGYJMC-UHFFFAOYSA-N Hydrochloric acid Chemical compound Cl VEXZGXHMUGYJMC-UHFFFAOYSA-N 0.000 claims description 32
- 239000002585 base Substances 0.000 claims description 22
- 239000000047 product Substances 0.000 claims description 12
- 238000004017 vitrification Methods 0.000 claims description 12
- TVFDJXOCXUVLDH-UHFFFAOYSA-N caesium atom Chemical compound [Cs] TVFDJXOCXUVLDH-UHFFFAOYSA-N 0.000 claims description 11
- -1 hexacyanoferrate ions Chemical class 0.000 claims description 11
- KWYUFKZDYYNOTN-UHFFFAOYSA-M Potassium hydroxide Chemical compound [OH-].[K+] KWYUFKZDYYNOTN-UHFFFAOYSA-M 0.000 claims description 9
- 238000005342 ion exchange Methods 0.000 claims description 9
- 229910052751 metal Inorganic materials 0.000 claims description 9
- 239000002184 metal Substances 0.000 claims description 9
- 150000003839 salts Chemical class 0.000 claims description 9
- 238000006386 neutralization reaction Methods 0.000 claims description 8
- HEMHJVSKTPXQMS-UHFFFAOYSA-M Sodium hydroxide Chemical group [OH-].[Na+] HEMHJVSKTPXQMS-UHFFFAOYSA-M 0.000 claims description 5
- 239000007787 solid Substances 0.000 claims description 5
- 238000000108 ultra-filtration Methods 0.000 claims description 4
- 150000008044 alkali metal hydroxides Chemical class 0.000 claims description 3
- 238000005554 pickling Methods 0.000 claims description 3
- 239000011343 solid material Substances 0.000 claims description 3
- 238000010306 acid treatment Methods 0.000 claims description 2
- 239000000446 fuel Substances 0.000 claims description 2
- 239000012265 solid product Substances 0.000 claims description 2
- 238000005406 washing Methods 0.000 claims 1
- 229910052712 strontium Inorganic materials 0.000 abstract description 3
- 230000003588 decontaminative effect Effects 0.000 description 3
- 238000000926 separation method Methods 0.000 description 3
- KRHYYFGTRYWZRS-UHFFFAOYSA-N Fluorane Chemical compound F KRHYYFGTRYWZRS-UHFFFAOYSA-N 0.000 description 2
- MHAJPDPJQMAIIY-UHFFFAOYSA-N Hydrogen peroxide Chemical compound OO MHAJPDPJQMAIIY-UHFFFAOYSA-N 0.000 description 2
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 2
- WCUXLLCKKVVCTQ-UHFFFAOYSA-M Potassium chloride Chemical compound [Cl-].[K+] WCUXLLCKKVVCTQ-UHFFFAOYSA-M 0.000 description 2
- 229910052739 hydrogen Inorganic materials 0.000 description 2
- 239000001257 hydrogen Substances 0.000 description 2
- CIOAGBVUUVVLOB-UHFFFAOYSA-N strontium atom Chemical compound [Sr] CIOAGBVUUVVLOB-UHFFFAOYSA-N 0.000 description 2
- 239000002699 waste material Substances 0.000 description 2
- VEXZGXHMUGYJMC-UHFFFAOYSA-M Chloride anion Chemical compound [Cl-] VEXZGXHMUGYJMC-UHFFFAOYSA-M 0.000 description 1
- 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 1
- GRYLNZFGIOXLOG-UHFFFAOYSA-N Nitric acid Chemical compound O[N+]([O-])=O GRYLNZFGIOXLOG-UHFFFAOYSA-N 0.000 description 1
- NPYPAHLBTDXSSS-UHFFFAOYSA-N Potassium ion Chemical compound [K+] NPYPAHLBTDXSSS-UHFFFAOYSA-N 0.000 description 1
- 150000007513 acids Chemical class 0.000 description 1
- 239000011248 coating agent Substances 0.000 description 1
- 238000000576 coating method Methods 0.000 description 1
- 238000010960 commercial process Methods 0.000 description 1
- 238000011109 contamination Methods 0.000 description 1
- 229910052742 iron Inorganic materials 0.000 description 1
- 239000010808 liquid waste Substances 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 239000007769 metal material Substances 0.000 description 1
- 229910017604 nitric acid Inorganic materials 0.000 description 1
- 239000007800 oxidant agent Substances 0.000 description 1
- 235000021110 pickles Nutrition 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
- 235000011164 potassium chloride Nutrition 0.000 description 1
- 229910001414 potassium ion Inorganic materials 0.000 description 1
- 238000001556 precipitation Methods 0.000 description 1
- 230000008929 regeneration Effects 0.000 description 1
- 238000011069 regeneration method Methods 0.000 description 1
- 229910001220 stainless steel Inorganic materials 0.000 description 1
- 239000010935 stainless steel Substances 0.000 description 1
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 1
Classifications
-
- C—CHEMISTRY; METALLURGY
- C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
- C23G—CLEANING OR DE-GREASING OF METALLIC MATERIAL BY CHEMICAL METHODS OTHER THAN ELECTROLYSIS
- C23G1/00—Cleaning or pickling metallic material with solutions or molten salts
- C23G1/36—Regeneration of waste pickling liquors
-
- 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
- C01B7/01—Chlorine; Hydrogen chloride
- C01B7/07—Purification ; Separation
- C01B7/0706—Purification ; Separation of hydrogen chloride
-
- G—PHYSICS
- G21—NUCLEAR PHYSICS; NUCLEAR ENGINEERING
- G21F—PROTECTION AGAINST X-RADIATION, GAMMA RADIATION, CORPUSCULAR RADIATION OR PARTICLE BOMBARDMENT; TREATING RADIOACTIVELY CONTAMINATED MATERIAL; DECONTAMINATION ARRANGEMENTS THEREFOR
- G21F9/00—Treating radioactively contaminated material; Decontamination arrangements therefor
- G21F9/001—Decontamination of contaminated objects, apparatus, clothes, food; Preventing contamination thereof
- G21F9/002—Decontamination of the surface of objects with chemical or electrochemical processes
- G21F9/004—Decontamination of the surface of objects with chemical or electrochemical processes of metallic surfaces
-
- G—PHYSICS
- G21—NUCLEAR PHYSICS; NUCLEAR ENGINEERING
- G21F—PROTECTION AGAINST X-RADIATION, GAMMA RADIATION, CORPUSCULAR RADIATION OR PARTICLE BOMBARDMENT; TREATING RADIOACTIVELY CONTAMINATED MATERIAL; DECONTAMINATION ARRANGEMENTS THEREFOR
- G21F9/00—Treating radioactively contaminated material; Decontamination arrangements therefor
- G21F9/04—Treating liquids
- G21F9/06—Processing
Landscapes
- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Organic Chemistry (AREA)
- Physics & Mathematics (AREA)
- Chemical Kinetics & Catalysis (AREA)
- General Chemical & Material Sciences (AREA)
- High Energy & Nuclear Physics (AREA)
- General Engineering & Computer Science (AREA)
- Materials Engineering (AREA)
- Life Sciences & Earth Sciences (AREA)
- Food Science & Technology (AREA)
- Electrochemistry (AREA)
- Metallurgy (AREA)
- Mechanical Engineering (AREA)
- Inorganic Chemistry (AREA)
- Water Treatment By Electricity Or Magnetism (AREA)
- Separation Using Semi-Permeable Membranes (AREA)
Abstract
A process for the treatment of a acid eg HCl contaminated with fission products (eg Cs or Sr) comprises, <SL> <LI>(i) neutralising the contaminated acid with a base; <LI>(ii) removal of radioactive components as one or more metal hydroxide flocs to produce a electrodialysis feedstock; <LI>(iii) treating the electrodialysis feedstock by passing it through a bipolar membrane to produce acid and base; and <LI>(iv) recycling the acid. </SL> The process is particularly suitable for a closed loop decontamination process. There is also described a plant for use in the process described.
Description
WASTE TREATMENT
This invention relates to a novel process for waste treatment.
Hydrochloric is used in the nuclear industry to remove a surface coating of fission products from metal based material, for example, a metal may be dipped into hydrochloric acid to remove any radioactive contamination, inter alia, caesium and/or strontium. However, this leaves the hydrochloric acid radioactively contaminated which necessitates the treatment of the spent acid.
Current processes of treating the contaminated surfaces include the utilisation of an acid with an oxidising agent, such as hydrogen peroxide. This allows fission products to be rapidly dissolved. The liquor formed is subsequently neutralised to form a floc which will aid the precipitation of some radioisotopes. However, certain isotopes, such as caesium and strontium do not floc well and therefore there has long been a need for an improved method of recycling the acid.
Byszerski, et al in Iron and Steel Engineer, have published"AQUATECH System-A commercial process to recycle spent pickle liquor"and describe an electrodialytic process which facilitates the separation of a salt stream into its acid and base components by the use of a bipolar membrane. Byszewski specifically describes the regeneration of spent nitric acid and hydrofluoric acid used in pickling stainless steel.
However, there is no disclosure that the process can be used in the separation of fission products from an acid stream.
We have now surprisingly found that a bipolar membrane may be used in relation to the treatment of hydrochloric acid in the nuclear industry.
According to the invention we provide a process for the treatment of an acid contaminated with fission products, which comprises,
(i) neutralising the acid with a base;
(ii) removal of radioactive components as one or more metal salt floes to, produce an electrodialysis feedstock;
(iii) treating the electrodialysis feedstock by passing it through a bipolar membrane to produce separated acid and base; and
(iv) recycling the acid.
The process of the invention may be applied to various fission product contaminated acids, but it is especially suitable for use in the recycling of hydrochloric acid.
The base may be selected from any conventionally used bases. However, preferred bases are alkali metal hydroxides, such as sodium or potassium hydroxide. The neutralisation step may be carried out to produce liquors of pH from 5 to 10.
The process of the invention may include further advantageous steps. Thus, the neutralisation step may include an ultrafiltration facility for removal of the metal salt floc, e. g. as a metal hydroxide. Since the flocculated solid may contain various radionuclides the solid may also be subjected to a vitrification or cementation step so that the radionuclides are immobilised.
In addition, following ultrafiltration the neutralised acid may be passed through an ion exchange column in order to remove trace radionuclides. The isolated trace radionuclides may be subjected to the same or an analogous vitrification or cementation process as the flocculated radionuclides. Such ion exchange columns are conventionally known to one skilled in the art.
Since radioactive caesium is a common fission product in a nuclear reactor, it may be advantageous to include a further step for the removal of caesium. Such a step, for example, includes treatment with hexacyanoferrate ions which can produce a solid material that may be subjected to vitrification or cementation. Alternatively, caesium treatment may be included in an ion exchange treatment.
The continuous use of an ion exchange system may require the column to be cleaned, e. g. by treatment with acid. In such cases the preferred acid of choice would be hydrochloric acid which may advantageously be recycled into the acid treatment process described herein.
Thus according to a further aspect of the present invention we provide a process for the treatment of hydrochloric acid contaminated with fission products which comprises ;
(i) neutralising the hydrochloric acid with a base ;
(ii) removal of radioactive components as one or more metal salt flocs to produce an electrodialysis feedstock, said solids being subsequently subjected to a vitrification or cementation process;
(iii) passing the electrodialysis feedstock down an ion exchange column and treating separated caesium with hexacyanoferrate ions and subjecting the solid product to a vitrification or cementation process, which may optionally be as (ii) above;
(iv) treating the electrodialysis feedstock by passing it through a bipolar membrane to produce hydrochloric acid and base;
(v) transferring the acid to an acid tank and the base to a base tank, said base being reusable in further neutralisation and said acid being reusable as a metal pickling acid.
According to a further feature of the invention we provide a plant for use in the process of the invention as hereinbefore described. An advantageous aspect of the plant of the invention is that it may be constructed as a mobile plant.
The process of the invention is especially advantageous because, inter alia, it provides a closed loop for the decontamination of fission product contaminated acid, eg hydrochloric acid. Thus, it is also advantageous in that the invention provides a closed loop decontamination plant adapted for the decontamination of fission product contaminated acid, which plant produces a minimum of liquid waste material.
The invention will now be described by way of example only and with reference to the accompanying in which Figure 1 is a schematic representation of the electrodialytic acid splitting process of the invention; and
Figure 2 is a schematic flow chart representing the plant of the invention.
With reference to Figure 1, an electrodialysis system (1) comprises a negatively charged polar membrane (2), comprises a positively charged polar membrane (3) and two bipolar membranes (4 and 5). The membrane system is placed between a cathode (6) and an anode (7). Neutralised hydrochloric acid solution is introduced to the system, e. g. as an aqueous potassium chloride solution, the potassium cations and chloride anions are separated and pass through the positive and negatively charged membranes (3 and 2) respectively. Water in the system is broken down by the bipolar membranes (4 and 5) to produce hydrogen cations and hydroxide anions. The bipolar membranes (4 and 5) are arranged so that only hydroxide anions will leave the chloride ion chamber and only hydrogen cations will leave the potassium ion chamber. Thus, the resulting hydrochloric acid and potassium hydroxide may be removed from the system (1) separately.
With reference to Figure 2 a plant (8) is represented for the electrodialytic recycling of hydrochloric acid contaminated with fission products comprises a neutralisation tank (9) and optionally an ultrafiltration tank, from which radionuclide solid residues may be removed to a cementation or vitrification unit (10) for ultimate disposal.
Liquors from the neutralisation tank may optionally be passed down an ion exchange column (11) and/or treated for the separation of caesium residues with hexacyanoferrate ions. Separated caesium may also be subjected to a vitrification or cementation process. The resulting liquors are then sent to an electrodialytic salt splitting unit (1) which comprises a bipolar membrane which reproduces the free acid and base.
The base may be recycled to a storage tank (12) for further use in neutralisation of contaminated acid. Similarly the acid may be recycled to a storage tank (13) for further use in fuel rod cleansing.
Claims (19)
- CLAIMS 1. A process for the treatment of an acid contaminated with fission products which comprises, (i) neutralising the contaminated acid with a base; (ii) removal of radioactive components as one or more metal hydroxide flocs to produce an electrodialysis feedstock; (iii) treating the electrodialysis feedstock by passing it through a bipolar membrane to produce acid and base; and (iv) recycling the acid.
- 2. A process according to Claim 1 in which the base is also recycled.
- 3. A process according to Claim 1 in which the acid is hydrochloric acid.
- 4. A process according to Claims 1 or 2 in which the base is an alkali metal hydroxide.
- 5. A process according to claim 4 in which the alkali metal hydroxide is selected from sodium hydroxide and potassium hydroxide.
- 6. A process according to Claim 1 in which the neutralisation step is followed by an ultrafiltration step adapted to remove metal salt floc.
- 7. A process according to Claim 6 in which the metal salt floc is a metal hydroxide.
- 8. A process according to Claim 6 in which the metal salt floc is subsequently subjected to vitrification or cementation.
- 9. A process according to Claims 1 or 6 in which the electrodialyis feedstock is passed through an ion exchange column in order to remove trace radionuclides.
- 10. A process according to Claim 9 in which the trace radionuclides are subsequently subjected to vitrification or cementation.
- 11. A process according to Claim 9 in which a further step is included for the removal of caesium.
- 12. A process according to Claim 11 in which the removal of caesium includes treatment with hexacyanoferrate ions to produce a substantially solid material.
- 13. A process according to Claim 12 in which the solid material is subjected to vitrification or cementation.
- 14 A process according to Claim 9 in which the ion exchange column is washed with an acid and the washings are recycled in the acid treatment
- 15. A process for the treatment of hydrochloric acid contaminated with fission products which comprises; (i) neutralising the hydrochloric acid with a base; (ii) removal of radioactive components as one or more metal salt flocs to produce an electrodialysis feedstock, said solids being subsequently subjected to a vitrification or cementation process; (iii) passing the electrodialysis feedstock down an ion exchange column and treating separated caesium with hexacyanoferrate ions and subjecting the solid product to a vitrification or cementation process, which may optionally be as (ii) above; (iv) treating the electrodialysis feedstock by passing it through a bipolar membrane to produce hydrochloric acid and base; (v) transferring the acid to an acid tank and the base to a base tank, said base being reusable in further neutralisation and said acid being reusable as a fuel pickling acid.
- 16. A plant for use in the process according to Claim 1.
- 17. A plant according to Claim 16 which is a mobile plant.
- 18. A process according to Claim 1 which is a closed loop decontamination process.
- 19. A process substantially as described with reference to the accompanying drawings.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GBGB9826710.7A GB9826710D0 (en) | 1998-12-05 | 1998-12-05 | Waste treatment |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| GB9926831D0 GB9926831D0 (en) | 2000-01-12 |
| GB2344340A true GB2344340A (en) | 2000-06-07 |
Family
ID=10843669
Family Applications (2)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GBGB9826710.7A Ceased GB9826710D0 (en) | 1998-12-05 | 1998-12-05 | Waste treatment |
| GB9926831A Withdrawn GB2344340A (en) | 1998-12-05 | 1999-11-15 | Treating acid contaminated with fission products |
Family Applications Before (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GBGB9826710.7A Ceased GB9826710D0 (en) | 1998-12-05 | 1998-12-05 | Waste treatment |
Country Status (1)
| Country | Link |
|---|---|
| GB (2) | GB9826710D0 (en) |
Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH08240695A (en) * | 1995-03-02 | 1996-09-17 | Ngk Insulators Ltd | Treatment method of radioactive waste liquid |
| JPH08271692A (en) * | 1995-03-28 | 1996-10-18 | Toshiba Corp | Processing method for radioactive waste liquid |
-
1998
- 1998-12-05 GB GBGB9826710.7A patent/GB9826710D0/en not_active Ceased
-
1999
- 1999-11-15 GB GB9926831A patent/GB2344340A/en not_active Withdrawn
Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH08240695A (en) * | 1995-03-02 | 1996-09-17 | Ngk Insulators Ltd | Treatment method of radioactive waste liquid |
| JPH08271692A (en) * | 1995-03-28 | 1996-10-18 | Toshiba Corp | Processing method for radioactive waste liquid |
Non-Patent Citations (2)
| Title |
|---|
| WPI abstract 1996-473296 & JP 08 240 695 A * |
| WPI abstract 1997-002792 & JP 08 271 692 A * |
Also Published As
| Publication number | Publication date |
|---|---|
| GB9826710D0 (en) | 1999-01-27 |
| GB9926831D0 (en) | 2000-01-12 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| WAP | Application withdrawn, taken to be withdrawn or refused ** after publication under section 16(1) |