CA1037844A - Regeneration process - Google Patents
Regeneration processInfo
- Publication number
- CA1037844A CA1037844A CA203,001A CA203001A CA1037844A CA 1037844 A CA1037844 A CA 1037844A CA 203001 A CA203001 A CA 203001A CA 1037844 A CA1037844 A CA 1037844A
- Authority
- CA
- Canada
- Prior art keywords
- mixture
- substance
- biuret
- converting agent
- baking
- 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.)
- Expired
Links
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
- C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
- C23C8/00—Solid state diffusion of only non-metal elements into metallic material surfaces; Chemical surface treatment of metallic material by reaction of the surface with a reactive gas, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals
- C23C8/40—Solid state diffusion of only non-metal elements into metallic material surfaces; Chemical surface treatment of metallic material by reaction of the surface with a reactive gas, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals using liquids, e.g. salt baths, liquid suspensions
Landscapes
- Chemical & Material Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Engineering & Computer Science (AREA)
- Materials Engineering (AREA)
- Mechanical Engineering (AREA)
- Metallurgy (AREA)
- Organic Chemistry (AREA)
- Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
- Water Treatment By Sorption (AREA)
- Removal Of Specific Substances (AREA)
- Solid-Sorbent Or Filter-Aiding Compositions (AREA)
Abstract
ABSTRACT OF THE DISCLOSURE:
The invention relates to a method of regeneration of a bath of molten salts including cyanates and carbonates, by the addition to said bath of an agent for converting the inactive carbonate principle to an active cyanate principle, in which said converting agent is prepared from at least one substance comprising at least one amide function and subjected to a treat-ment for the liberation of gaseous ammonia. This method has an industrial use, especially for the surface treatment of metals.
The invention relates to a method of regeneration of a bath of molten salts including cyanates and carbonates, by the addition to said bath of an agent for converting the inactive carbonate principle to an active cyanate principle, in which said converting agent is prepared from at least one substance comprising at least one amide function and subjected to a treat-ment for the liberation of gaseous ammonia. This method has an industrial use, especially for the surface treatment of metals.
Description
~)37844 The present invention relates to a method of regeneration of a bath of molten salts, especially for the surface treatment of metals.
Molten salt baths are known for the surface-treatment of metals in which the active principle comprises, inter alia, cyanates and cyanides. Baths of this kind tend to form carbonates by oxidation, which are practically without any action.
There exist three kinds of degeneration or consump- ~ -tion of these baths: ~ -1) The parts treated carry away with them the salt with which they are wetted,
Molten salt baths are known for the surface-treatment of metals in which the active principle comprises, inter alia, cyanates and cyanides. Baths of this kind tend to form carbonates by oxidation, which are practically without any action.
There exist three kinds of degeneration or consump- ~ -tion of these baths: ~ -1) The parts treated carry away with them the salt with which they are wetted,
2) the treatment itself establishes an interaction between -~
the metal and the bath which creates insoluble products and sludges:
the metal and the bath which creates insoluble products and sludges:
3) Permanent oxidation by the atmosphere or the blowing air causes the composition of the bath to change continually ~ ~
cyanides being converted to cyanates and cyanates to ~ ~ -carbonates, in other words, the ultimate term of this degeneration by oxidation is an inactive product.
Addition salts have already been proposed which have the effect of re-converting the inactive carbonate -principle to an active cyanate principle. One of these addition salts already proposed is carbamide, also known as ~ -urea, having the formula CO(NH2)2.
This meanls is an industrial use which is difficult, or at least which necessitates certain precautions, due to the violent liberation of ammonia which results from the action of the urea on the carbonates in the bath.
" .:
The present inve~tion provides a remedy for these disadvantages and proposes to this end, a method , ~ ~
- 2 - ~
- . . ,.. ,. . , ...... . . , , . : .
, . , , - , - .
, . , .. .. .: ',' - - .,~. ' - ' . ' of regeneration of a bath of molten salts containing cyanates and carbonates, which comprises adding to the bath an agent for converting inactive carbonate to active cyanate in an amount sufficient to substantially prevent the build up of inactive carbonate degeneration products in the bath when said bath is employed in molten form for the surface treatment of metals.
This method is characterized in that the conversion agent is pre-pared before its addition to the bath by subjecting at least one substance comprising at least one amide function to a treatment which liberates a portion of the contained nitrogen as gaseous ammonia while retaining another portion of the contained nitrogen in a form suitable for reaction with carbonates to form cyanates. The liberated portion of nitrogen contained in the substance corresponds to that which would be violently liberated in the form of ammonia in the instance of employing the untreated substance in the bath.
This method advantageously ensures regeneration of earbonates by eonversion to eyanates with much less considerable evolution of gas which is mueh less rieh in ammonia than in the known ease previously eited, whieh faeilitates its industrial applieation.
` The converting agent may be a single produet, for example biuret or diaeetamide, ete., but also it may be a mixture of several produets obtained from one or more substanees eapable of liberating ammonia gas, and of whieh at least one and preferably eaeh substanee eomprises at least one amide funetion.
The treatment for liberation of ammonia gas may either be a baking or another treatment, in partieular a ehemieal attaek, for example by ethyl-earbamate.
The subjeet invention will be better understood with referenee to the following non restrietive examples.
~ - 3 -C ~.
-' ' ; . - ' -~.
~037844 EXA~LE 1 A bath of molten salts for the surface treatmentof metals, comprises 35% of active cyanate radical CNO and 25% of the inactive carbonate radical C03 . :
This bath tends to form carbonates by oxidation, which are ~uo~tan =lly without action.
`~
,:
''i -'.
~;.''" ' ~'- " -/
, ':. .
.
- 3 a -C ' "'~' '';
, ~ . - ~ .. : . -. . ... . . .
~037B44 In order to regenerate the bath, there is added to it a converting agent for changing the inactive carbonate principle to the active cyanate principle.
This converting agent is chosen in such manner as ~ - -not to cause any violent liberation of ammonia gas in the bath, as is especially the case when this agent consists, in the usual way, of carbamide, also known as urea, having the formula CO(NH2)2 .
To this end, according to the invention, the converting agent is such that for its preparation, at least one substance comprising at least one amide function is subjected to a liberation treatment of ammonia gas. -In the present example, one single substance is -provided, and the converting agent consists of a single product, while the liberation treatment of ammonia gas which produces this converting agent from the said substance, consists of a baking operation of the said substance.
More particularly, the starting substance is carbamide, also known as urea, having the formula CO(NH2)2, ;~
comprising at least one amide function.
The urea is treated by baking at 160C, and the following reaction takes place:
2CO(NH2)2 >~H2 - C0 - NH - C0 - NH2 + NH3 After baking for an hour and a half, there remains substantially the substance NH2 ~ C0 - NH - C0 - NH2 known as biuret. It is thislbiuret which constitutes the converting agent of the inactive carbonate principle to the active cyanate principle.
By adding the biuret in a bath of molten salts comprising cyanates and carbonates for the surface treatment of metals, there is ensured an excellent regeneration of this bath without excessive liberation of gas.
- : ,: . ...
.~. j , . . .
~ -~ -. ~ ' :, : - . .
~; - - , : : ~ ., .
r~
; ~
EXAMPLE II
As in Example 1, the single starting substance comprises an amide function capable of liberating gaseous - ~ -ammonia in order to produce a converting agent constituted -by a single product.
This substance however, instead of being a carbamide, also known as urea, is acetamide which comprises an amide function, and this converting agent, instead of being biuret is diacetamide.
More particularly, the acetamide is baked at a -~
temperature of 220C. for one and a half hours, which enables -diacetamide to be obtained.
This diacetamide is utilized as the converting agent of the inactive carbonate principle to the active cyanate principle so as to regenerate a bath of molten salts comprising carbonates and cyanates for the surface treatment of metals, without giving rise to excessive evolution of gas.
EXAMPLE III
As in Example I or in Example II, the single starting substance comprises an amide function adapted to liberate gaseous ammonia in order to produce a converting agent, but this latter is constituted by a mixture of products instead of by a single product.
This single substance is acetamide and the mixture of products constituting the converting agent is a mixture of diacetamide and ~socyanic acid.
More particularly, the acetamide is baked at a temperature of 260C. for three hours, which enables dia-cetamide and isocyanic acid to be obtained simultaneously.
EXAMPLE IV
The starting substance comprises at least one amide function which is baked under conditions of temperature ~
_ 5 _ .,'' ~, ,, ~.
:; .' "
.
1037~44 such that there is not only liberation of geseous ammonia but also, as in Example III, the simultaneous formation of several products, the whole of which constitutes the converting agent.
To this end, for example, the following procedure is adopted:
By baking carbamide, also known as urea, at 300C.
there can be obtained simultaneously biuret, ammelide, - -guanidine, isocyanic acid. The urea is the starting substance:
it actually comprises an amide function, its baking at 300C.
liberates gaseous ammonia and leads to the production of a mixture of several pro~ucts, the said mixture of products constituting the converting agent.
EXAMPLE V
Several starting substances are baked separately, and there are obtained separately several products, the mixture of which constitutes the converting agent.
For that purpose, the following procedure is adopted for example:
By baking acetamide at 260C, there are obtained simultaneously diacetamide and isocyanic acid, with liberation of ammonia.
By baking carbamide or urea at 160C, biuret is obtained as in Example 1, with liberation of ammonia in this case also.
The mixtu~e of diacetamide, isocyanic acid and biuret constitutes the converting agent.
EXAMPLE VI
The starting mixture comprises several substances each containing at least one amide function. This mixture is baked and there is obtained, in addition to the liberation of gaseous ammonia, a mixture of products which - .~ . ' . .
. .:
..
form the converting agent.
For this purpose, for example, the following procedure is adopted:
The starting mixture is a mixture of carbamide or urea and acetamide, which each contain an amide function, and this mixture is baked at 300C. This baking is accompanied by the evolution of ammonia gas. There is obtained a mixture of biuret, ammelide, ammeline, isocyanic acid, guanidine, diacetamide, and triacetamide, which constitute the converting agent.
EXAMPLE VII
In the pr ceding Examples, the baking is utilized as the means of treatment for the liberation of ammonia gas, but there could also be employed any other form of treatment, .. ;, - ~ . .. .
for example a chemical attack, as indicated below.
As the starting substance, there is utilized biuret -which comprises two amide functions and which is attacked chemically by ethyl-carbamate. There is thus obtained a substance having the chemical formula (HCN0)3, 2H20 which 20 constitutes the converting agent. ~;
- This chemical attack of the biuret is accompanied by the evolution of gaseous ammonia, so that the regeneration of the bath of molten salts by means of (HCN0)3, 2H20 gives rise to a liberation of gas which is still less than when the biuret is directly utilized as the converting agent, `
as in Example 1.
It wlll or course be understood that all the examples described above are given in a non-limitative sense, and that any product or mixture obtained from one or more 30 substances each comprising at least one amide function and capable of being subjected to a treatment of liberation of gaseous ammonia forma part of the invention and can be ~ -utilized as a converting agent. ;~
_ 7 -' .'. ' i ,: ~ i , ' , ,.. ;;:. ,. ~., , ; , , ~., : .. . . .. ..
cyanides being converted to cyanates and cyanates to ~ ~ -carbonates, in other words, the ultimate term of this degeneration by oxidation is an inactive product.
Addition salts have already been proposed which have the effect of re-converting the inactive carbonate -principle to an active cyanate principle. One of these addition salts already proposed is carbamide, also known as ~ -urea, having the formula CO(NH2)2.
This meanls is an industrial use which is difficult, or at least which necessitates certain precautions, due to the violent liberation of ammonia which results from the action of the urea on the carbonates in the bath.
" .:
The present inve~tion provides a remedy for these disadvantages and proposes to this end, a method , ~ ~
- 2 - ~
- . . ,.. ,. . , ...... . . , , . : .
, . , , - , - .
, . , .. .. .: ',' - - .,~. ' - ' . ' of regeneration of a bath of molten salts containing cyanates and carbonates, which comprises adding to the bath an agent for converting inactive carbonate to active cyanate in an amount sufficient to substantially prevent the build up of inactive carbonate degeneration products in the bath when said bath is employed in molten form for the surface treatment of metals.
This method is characterized in that the conversion agent is pre-pared before its addition to the bath by subjecting at least one substance comprising at least one amide function to a treatment which liberates a portion of the contained nitrogen as gaseous ammonia while retaining another portion of the contained nitrogen in a form suitable for reaction with carbonates to form cyanates. The liberated portion of nitrogen contained in the substance corresponds to that which would be violently liberated in the form of ammonia in the instance of employing the untreated substance in the bath.
This method advantageously ensures regeneration of earbonates by eonversion to eyanates with much less considerable evolution of gas which is mueh less rieh in ammonia than in the known ease previously eited, whieh faeilitates its industrial applieation.
` The converting agent may be a single produet, for example biuret or diaeetamide, ete., but also it may be a mixture of several produets obtained from one or more substanees eapable of liberating ammonia gas, and of whieh at least one and preferably eaeh substanee eomprises at least one amide funetion.
The treatment for liberation of ammonia gas may either be a baking or another treatment, in partieular a ehemieal attaek, for example by ethyl-earbamate.
The subjeet invention will be better understood with referenee to the following non restrietive examples.
~ - 3 -C ~.
-' ' ; . - ' -~.
~037844 EXA~LE 1 A bath of molten salts for the surface treatmentof metals, comprises 35% of active cyanate radical CNO and 25% of the inactive carbonate radical C03 . :
This bath tends to form carbonates by oxidation, which are ~uo~tan =lly without action.
`~
,:
''i -'.
~;.''" ' ~'- " -/
, ':. .
.
- 3 a -C ' "'~' '';
, ~ . - ~ .. : . -. . ... . . .
~037B44 In order to regenerate the bath, there is added to it a converting agent for changing the inactive carbonate principle to the active cyanate principle.
This converting agent is chosen in such manner as ~ - -not to cause any violent liberation of ammonia gas in the bath, as is especially the case when this agent consists, in the usual way, of carbamide, also known as urea, having the formula CO(NH2)2 .
To this end, according to the invention, the converting agent is such that for its preparation, at least one substance comprising at least one amide function is subjected to a liberation treatment of ammonia gas. -In the present example, one single substance is -provided, and the converting agent consists of a single product, while the liberation treatment of ammonia gas which produces this converting agent from the said substance, consists of a baking operation of the said substance.
More particularly, the starting substance is carbamide, also known as urea, having the formula CO(NH2)2, ;~
comprising at least one amide function.
The urea is treated by baking at 160C, and the following reaction takes place:
2CO(NH2)2 >~H2 - C0 - NH - C0 - NH2 + NH3 After baking for an hour and a half, there remains substantially the substance NH2 ~ C0 - NH - C0 - NH2 known as biuret. It is thislbiuret which constitutes the converting agent of the inactive carbonate principle to the active cyanate principle.
By adding the biuret in a bath of molten salts comprising cyanates and carbonates for the surface treatment of metals, there is ensured an excellent regeneration of this bath without excessive liberation of gas.
- : ,: . ...
.~. j , . . .
~ -~ -. ~ ' :, : - . .
~; - - , : : ~ ., .
r~
; ~
EXAMPLE II
As in Example 1, the single starting substance comprises an amide function capable of liberating gaseous - ~ -ammonia in order to produce a converting agent constituted -by a single product.
This substance however, instead of being a carbamide, also known as urea, is acetamide which comprises an amide function, and this converting agent, instead of being biuret is diacetamide.
More particularly, the acetamide is baked at a -~
temperature of 220C. for one and a half hours, which enables -diacetamide to be obtained.
This diacetamide is utilized as the converting agent of the inactive carbonate principle to the active cyanate principle so as to regenerate a bath of molten salts comprising carbonates and cyanates for the surface treatment of metals, without giving rise to excessive evolution of gas.
EXAMPLE III
As in Example I or in Example II, the single starting substance comprises an amide function adapted to liberate gaseous ammonia in order to produce a converting agent, but this latter is constituted by a mixture of products instead of by a single product.
This single substance is acetamide and the mixture of products constituting the converting agent is a mixture of diacetamide and ~socyanic acid.
More particularly, the acetamide is baked at a temperature of 260C. for three hours, which enables dia-cetamide and isocyanic acid to be obtained simultaneously.
EXAMPLE IV
The starting substance comprises at least one amide function which is baked under conditions of temperature ~
_ 5 _ .,'' ~, ,, ~.
:; .' "
.
1037~44 such that there is not only liberation of geseous ammonia but also, as in Example III, the simultaneous formation of several products, the whole of which constitutes the converting agent.
To this end, for example, the following procedure is adopted:
By baking carbamide, also known as urea, at 300C.
there can be obtained simultaneously biuret, ammelide, - -guanidine, isocyanic acid. The urea is the starting substance:
it actually comprises an amide function, its baking at 300C.
liberates gaseous ammonia and leads to the production of a mixture of several pro~ucts, the said mixture of products constituting the converting agent.
EXAMPLE V
Several starting substances are baked separately, and there are obtained separately several products, the mixture of which constitutes the converting agent.
For that purpose, the following procedure is adopted for example:
By baking acetamide at 260C, there are obtained simultaneously diacetamide and isocyanic acid, with liberation of ammonia.
By baking carbamide or urea at 160C, biuret is obtained as in Example 1, with liberation of ammonia in this case also.
The mixtu~e of diacetamide, isocyanic acid and biuret constitutes the converting agent.
EXAMPLE VI
The starting mixture comprises several substances each containing at least one amide function. This mixture is baked and there is obtained, in addition to the liberation of gaseous ammonia, a mixture of products which - .~ . ' . .
. .:
..
form the converting agent.
For this purpose, for example, the following procedure is adopted:
The starting mixture is a mixture of carbamide or urea and acetamide, which each contain an amide function, and this mixture is baked at 300C. This baking is accompanied by the evolution of ammonia gas. There is obtained a mixture of biuret, ammelide, ammeline, isocyanic acid, guanidine, diacetamide, and triacetamide, which constitute the converting agent.
EXAMPLE VII
In the pr ceding Examples, the baking is utilized as the means of treatment for the liberation of ammonia gas, but there could also be employed any other form of treatment, .. ;, - ~ . .. .
for example a chemical attack, as indicated below.
As the starting substance, there is utilized biuret -which comprises two amide functions and which is attacked chemically by ethyl-carbamate. There is thus obtained a substance having the chemical formula (HCN0)3, 2H20 which 20 constitutes the converting agent. ~;
- This chemical attack of the biuret is accompanied by the evolution of gaseous ammonia, so that the regeneration of the bath of molten salts by means of (HCN0)3, 2H20 gives rise to a liberation of gas which is still less than when the biuret is directly utilized as the converting agent, `
as in Example 1.
It wlll or course be understood that all the examples described above are given in a non-limitative sense, and that any product or mixture obtained from one or more 30 substances each comprising at least one amide function and capable of being subjected to a treatment of liberation of gaseous ammonia forma part of the invention and can be ~ -utilized as a converting agent. ;~
_ 7 -' .'. ' i ,: ~ i , ' , ,.. ;;:. ,. ~., , ; , , ~., : .. . . .. ..
Claims (27)
1. A method of regeneration of a bath of molten salts containing cyanates and carbonates, comprising adding to said bath an agent for converting inactive carbonate to active cyanate in an amount sufficient to substantially prevent the build up of inactive carbonate degeneration products in the bath when said bath is employed in molten form for the surface treatment of metals, said converting agent being prepared before addition to the bath by subjecting at least one substance comprising at least one amide function to a treatment which liberates a portion of the contained nitrogen as gaseous ammonia said liberated portion corresponding to that which would be violently operated in the form of ammonia in the instance of employing the untreated substance in the bath, while retaining another portion of the contained nitrogen in a form suitable for reaction with carbonates to form cyanates.
2. A method as claimed in claim 1, in which said treatment for the liberation of gaseous ammonia consists in baking said substance.
3. A method as claimed in claim 1, in which said treatment for the liberation of gaseous ammonia consists in a chemical attack on said substance.
4. A method as claimed in claim 1, in which said substance is a carbamide, also known as urea.
5. A method as claimed in claim 1, in which said converting agent is biuret.
6. A method as claimed in claim 5, in which said biuret is obtained by baking carbamide, also known as urea, at about 160°C.
7. A method as claimed in claim 1, in which said substance is acetamide.
8. A method as claimed in claim 1, in which said converting agent is diacetamide.
9. A method as claimed in claim 8, in which said diacetamide is obtained by baking acetamide at about 220°C.
10. A method as claimed in claim 1, in which said substance is biuret.
11. A method as claimed in claim 1, in which said converting agent is a substance having the chemical formula (HCNO)3, 2H2O.
12. A method as claimed in claim 11, in which said substance having the chemical formula (HCNO)3, 2H2O is obtained by the chemical attack on biuret by ethyl-carbamate.
13. A method as claimed in claim 1, in which said substance is single and gives rise to a converting agent constituted by a mixture of products.
14. A method as claimed in claim 13, in which said substance is acetamide.
15. A method as claimed in claim 13, in which said converting agent is a mixture of diacetamide and isocyanic acid.
16. A method as claimed in claim 15, in which said mixture of diacetamide and isocyanic acid is obtained by baking acetamide at about 260°C.
17. A method as claimed in claim 13, in which said substance is carbamide, also known as urea.
18. A method as claimed in claim 13, in which said converting agent is a mixture of biuret, ammelide, guanidine and isocyanic acid.
19. A method as claimed in claim 18, in which said mixture of biuret, ammelide, guanidine and isocyanic acid is obtained by baking carbamide, also known as urea, at about 300°C.
20. A method as claimed in claim 1, in which a plurality of substances are provided, and are separately subjected to treatments for the liberation of gaseous ammonia in order to give rise to products, the mixture of which constitutes said converting agent.
21. A method as claimed in claim 20, in which one of said substances is acetamide, while another of said substances is carbamide, also known as urea.
22. A method as claimed in claim 20, in which said mixture of products is constituted by diacetamide, isocyanic acid and biuret.
23. A method as claimed in claim 22, in which said diacetamide and isocyanic acid are obtained by baking acetamide at about 260°C., while the biuret is obtained by baking carbamide, also known as urea, at about 160°C.
24. A method as claimed in claim 1, in which a mixture of several substances such as said substance is provided, and is subjected to treatment for the liberation of gaseous ammonia in order to obtain a mixture of products constituting said converting agent.
25. A method as claimed in claim 24, in which said mixture of substances is constituted by a mixture of carbamide, also known as urea, and acetamide.
26. A method as claimed in claim 24, in which said converting agent is constituted by a mixture of biuret, ammelide, ammeline, isocyanic acid, guanidine, diacetamide and triecetamide.
27. A method as claimed in claim 26, in which said mixture of biuret, ammelide, ammeline, isocyanic acid, guanidine, diacetamide and triacetamide is obtained by baking said mixture of carbamide, also known as urea, and acetamide at about 300°C.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| FR7322400A FR2234380A1 (en) | 1973-06-20 | 1973-06-20 | Regenerating cyanate-carbonate molten salt baths - by adding amide pretreated to liberate ammonia |
| FR7416538A FR2271308A2 (en) | 1974-05-14 | 1974-05-14 | Regenerating cyanate-carbonate molten salt baths - by adding amide pretreated to liberate ammonia |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1037844A true CA1037844A (en) | 1978-09-05 |
Family
ID=26217778
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA203,001A Expired CA1037844A (en) | 1973-06-20 | 1974-06-20 | Regeneration process |
Country Status (12)
| Country | Link |
|---|---|
| JP (1) | JPS5068932A (en) |
| AR (1) | AR204533A1 (en) |
| BR (1) | BR7405013A (en) |
| CA (1) | CA1037844A (en) |
| CH (1) | CH593344A5 (en) |
| DD (1) | DD112667A5 (en) |
| DE (1) | DE2429679B2 (en) |
| ES (1) | ES427426A1 (en) |
| GB (1) | GB1433690A (en) |
| IT (1) | IT1011999B (en) |
| NL (1) | NL7408198A (en) |
| SE (1) | SE411461B (en) |
Families Citing this family (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5237524A (en) * | 1975-09-19 | 1977-03-23 | Seitarou Iwasaki | Method of stabilizing composition of carbonitriding salt bath |
| FR2556367B1 (en) * | 1983-12-09 | 1986-09-19 | Stephanois Rech Mec | INPUT LOAD FOR THE MAINTENANCE OF MOLTEN SALT BATHTUBS FOR THE TREATMENT OF METAL PARTS |
| DE4030279C1 (en) * | 1990-09-25 | 1992-06-04 | Goetz Dipl.-Chem. Dr. 5400 Koblenz De Baum | Regenerating molten alkali metal cyanate - by continuous addn. of urea] or polymer or condensate that generates urea, feeding additive into containers in continuous conveyor |
| DE4119820C1 (en) * | 1991-06-15 | 1992-09-03 | Goetz Dr. 5400 Koblenz De Baum | Treatment of iron@ (alloys) on same support - comprises nitriding in molten alkali metal cyanate and quenching in hot aq. salt bath |
-
1974
- 1974-01-01 AR AR254266A patent/AR204533A1/en active
- 1974-06-17 SE SE7407982A patent/SE411461B/en unknown
- 1974-06-18 IT IT68911/74A patent/IT1011999B/en active
- 1974-06-19 BR BR5013/74A patent/BR7405013A/en unknown
- 1974-06-19 NL NL7408198A patent/NL7408198A/xx not_active Application Discontinuation
- 1974-06-19 ES ES427426A patent/ES427426A1/en not_active Expired
- 1974-06-19 CH CH841774A patent/CH593344A5/xx not_active IP Right Cessation
- 1974-06-20 GB GB2741974A patent/GB1433690A/en not_active Expired
- 1974-06-20 CA CA203,001A patent/CA1037844A/en not_active Expired
- 1974-06-20 DE DE2429679A patent/DE2429679B2/en not_active Withdrawn
- 1974-06-20 JP JP49069738A patent/JPS5068932A/ja active Pending
- 1974-06-20 DD DD179327A patent/DD112667A5/xx unknown
Also Published As
| Publication number | Publication date |
|---|---|
| DE2429679B2 (en) | 1978-03-09 |
| GB1433690A (en) | 1976-04-28 |
| CH593344A5 (en) | 1977-11-30 |
| SE7407982L (en) | 1974-12-23 |
| DE2429679A1 (en) | 1975-01-09 |
| JPS5068932A (en) | 1975-06-09 |
| IT1011999B (en) | 1977-02-10 |
| ES427426A1 (en) | 1976-09-16 |
| DD112667A5 (en) | 1975-04-20 |
| NL7408198A (en) | 1974-12-24 |
| BR7405013A (en) | 1976-02-17 |
| BR7405013D0 (en) | 1975-01-07 |
| SE411461B (en) | 1979-12-27 |
| AR204533A1 (en) | 1976-02-12 |
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