US3468621A - Prevention of metal hydride decomposition - Google Patents
Prevention of metal hydride decomposition Download PDFInfo
- Publication number
- US3468621A US3468621A US548859A US3468621DA US3468621A US 3468621 A US3468621 A US 3468621A US 548859 A US548859 A US 548859A US 3468621D A US3468621D A US 3468621DA US 3468621 A US3468621 A US 3468621A
- Authority
- US
- United States
- Prior art keywords
- metal hydride
- decomposition
- metal
- hydride
- prevention
- 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 - Lifetime
Links
- 150000004681 metal hydrides Chemical class 0.000 title description 21
- 229910052987 metal hydride Inorganic materials 0.000 title description 20
- 238000000354 decomposition reaction Methods 0.000 title description 12
- 230000002265 prevention Effects 0.000 title description 3
- 239000007788 liquid Substances 0.000 description 13
- 238000000034 method Methods 0.000 description 11
- 229910000102 alkali metal hydride Inorganic materials 0.000 description 10
- 150000008046 alkali metal hydrides Chemical group 0.000 description 9
- KWYUFKZDYYNOTN-UHFFFAOYSA-M Potassium hydroxide Chemical compound [OH-].[K+] KWYUFKZDYYNOTN-UHFFFAOYSA-M 0.000 description 6
- HEMHJVSKTPXQMS-UHFFFAOYSA-M Sodium hydroxide Chemical compound [OH-].[Na+] HEMHJVSKTPXQMS-UHFFFAOYSA-M 0.000 description 6
- 150000004692 metal hydroxides Chemical class 0.000 description 6
- 239000000203 mixture Substances 0.000 description 6
- 239000011248 coating agent Substances 0.000 description 5
- 238000000576 coating method Methods 0.000 description 5
- 239000000155 melt Substances 0.000 description 5
- 230000008018 melting Effects 0.000 description 5
- 238000002844 melting Methods 0.000 description 5
- 229910000000 metal hydroxide Inorganic materials 0.000 description 5
- 230000005496 eutectics Effects 0.000 description 4
- 150000004678 hydrides Chemical class 0.000 description 4
- 229930195733 hydrocarbon Natural products 0.000 description 4
- 150000002430 hydrocarbons Chemical class 0.000 description 4
- 239000003921 oil Substances 0.000 description 4
- 239000004215 Carbon black (E152) Substances 0.000 description 3
- KEAYESYHFKHZAL-UHFFFAOYSA-N Sodium Chemical compound [Na] KEAYESYHFKHZAL-UHFFFAOYSA-N 0.000 description 3
- 150000008044 alkali metal hydroxides Chemical class 0.000 description 3
- 238000009835 boiling Methods 0.000 description 3
- 239000000374 eutectic mixture Substances 0.000 description 3
- 239000000463 material Substances 0.000 description 3
- 229910052751 metal Inorganic materials 0.000 description 3
- 239000002184 metal Substances 0.000 description 3
- 239000000047 product Substances 0.000 description 3
- 229910000104 sodium hydride Inorganic materials 0.000 description 3
- 239000012312 sodium hydride Substances 0.000 description 3
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 2
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 description 2
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 2
- 229910052783 alkali metal Inorganic materials 0.000 description 2
- 150000001340 alkali metals Chemical class 0.000 description 2
- 239000002360 explosive Substances 0.000 description 2
- -1 ferrous metals Chemical class 0.000 description 2
- 239000001257 hydrogen Substances 0.000 description 2
- 229910052739 hydrogen Inorganic materials 0.000 description 2
- 239000011261 inert gas Substances 0.000 description 2
- VGGSQFUCUMXWEO-UHFFFAOYSA-N Ethene Chemical compound C=C VGGSQFUCUMXWEO-UHFFFAOYSA-N 0.000 description 1
- 239000005977 Ethylene Substances 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
- WHXSMMKQMYFTQS-UHFFFAOYSA-N Lithium Chemical compound [Li] WHXSMMKQMYFTQS-UHFFFAOYSA-N 0.000 description 1
- 239000004698 Polyethylene Substances 0.000 description 1
- ZLMJMSJWJFRBEC-UHFFFAOYSA-N Potassium Chemical compound [K] ZLMJMSJWJFRBEC-UHFFFAOYSA-N 0.000 description 1
- 229910000831 Steel Inorganic materials 0.000 description 1
- 239000003513 alkali Substances 0.000 description 1
- 229910001854 alkali hydroxide Inorganic materials 0.000 description 1
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- 239000003054 catalyst Substances 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
- 239000013065 commercial product Substances 0.000 description 1
- 239000010779 crude oil Substances 0.000 description 1
- 238000004880 explosion Methods 0.000 description 1
- 239000007789 gas Substances 0.000 description 1
- 150000002431 hydrogen Chemical class 0.000 description 1
- 229910052742 iron Inorganic materials 0.000 description 1
- 229910001338 liquidmetal Inorganic materials 0.000 description 1
- 229910052744 lithium Inorganic materials 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 229910052757 nitrogen Inorganic materials 0.000 description 1
- 239000001301 oxygen Substances 0.000 description 1
- 229910052760 oxygen Inorganic materials 0.000 description 1
- 229920000573 polyethylene Polymers 0.000 description 1
- 229920000642 polymer Polymers 0.000 description 1
- 229920000098 polyolefin Polymers 0.000 description 1
- 229910052700 potassium Inorganic materials 0.000 description 1
- 239000011591 potassium Substances 0.000 description 1
- 229930195734 saturated hydrocarbon Natural products 0.000 description 1
- 229910052708 sodium Inorganic materials 0.000 description 1
- 239000011734 sodium Substances 0.000 description 1
- 239000011343 solid material Substances 0.000 description 1
- 239000010959 steel Substances 0.000 description 1
- 238000003786 synthesis reaction Methods 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
- C23G1/28—Cleaning or pickling metallic material with solutions or molten salts with molten salts
Definitions
- This invention relates to a method of preventing the decomposition of metal hydride. It more particularly refers to the prevention of decomposition of liquid mixtures of alkali hydroxides and metal hydrides.
- Metal descaling has become an important industrial process. It has been found that one particularly good descalant is a solution of a metal hydride, particularly an alkali metal hydride, in an eutectic or nearly eutectic mixture of metal hydroxides, particularly alkali metal hydroxides. Such descaling solutions are known to the art, see German patent application D 44,165 which corresponds to US. application Ser. No. 451,671, filed Apr. 15, 1965 now abandoned.
- the problem is that metal hydrides are quite reactive with the water content of the air such that the metal hydride decomposes and thus becomes unsuited to the use for which it or its solution was intended.
- one of the products of decomposition is hydrogen gas which, as is well known, is quite flammable and is explosive in certain proportions in admixture with air.
- the problem is three-fold: how to prevent metal hydride decomposition; how to prevent hydrogen ignition; and how to prevent explosion of hydrogen-air mixtures.
- this invention resides, in one of its broadest aspects, in providing a liquid coating for a descaling liquid soultion of metal hydride.
- the liquid coating In carrying out this invention, it is necessary for the liquid coating to have certain attributes. Such coating must be substantially immiscible and non-reactive with respect to the metal hydride or other components of the liquid it is coated upon. It must be a liquid at the temperatures of operation, must have a relatively low vapor pressure and flammability at these temperatures and must not decompose to any appreciable extent at these temperatures.
- One class of materials that has been found to be eminently suited to use in this invention possessing substantially all of the attributes required and set forth above, is relatively high molecular weight hydrocarbons, particularly paraflinic materials. These saturated hydrocarbons may be relatively low molecular weight olefin polymers or they may be naturally occurring or synthetic paratfin oils. Exemplary of the naturally occurring oils useful in this invention are crude oil fractions having melting points of about -50 to C. The commercial product Bayol marketed by Esso Standard Oil Company is exemplary of paratfins suited to use in this invention. Also suited are products of Fischer-Tropsch synthesis using cobalt catalysts in the known way.
- Oligomers and low molecular weight polymers of ethylene having molecular weights of about 3000 to 8000 are suited to use in this invention.
- Exemplary of the polyethylenes referred to are those marketed by BASF as Lupolen N and by US. Industries as Epolene.
- Paraflins should have boiling points at least about 20 C. higher than the hydride solution operating temperatures and should have melting points at least about 5 C. below such operating tempera ture.
- Example 1 An eutectic melt of sodium hydroxide mixed with potassium hydroxide was prepared containing 2% by weight sodium hydride. About eight (8) tons of this melt were disposed in a vessel such that the surface area of the melt was about five square meters. The bath temperature was brought to 230 C. and held there uncovered for about 48 hours after which time the sodium hydride content of the melt was measured to be 1% by weight.
- Example 2 Example 1 was repeated except that the surface of the melt was coated with about 5 millimeters of a white oil having no components which distilled below 300 C. No loss of metal hydride could be determined at the end of the 48 hour period.
- the method of preventing the decomposition of the alkali hydride content of a melt comprising a mixture of alkali metal hydride and alkali metal hydroxide which comprises coating said melt on the surface thereof which would otherwise be exposed to air, with a liquid layer of a parafiinic hydrocarbon which is substantially immiscible and non-reactive with said alkali metal hydride containing melt, has a boiling point at least about 20 C. higher than the temperature of said alkali metal hydride containing melt and has a melting point below the temperature of said alkali metal hydride containing bath.
- paraffinic hydrocarbon has a melting point of about to C.
- alkali metal is at least one member selected from the group consisting of sodium, potassium and lithium.
Landscapes
- Chemical & Material Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- General Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Materials Engineering (AREA)
- Mechanical Engineering (AREA)
- Metallurgy (AREA)
- Organic Chemistry (AREA)
- Detergent Compositions (AREA)
- Production Of Liquid Hydrocarbon Mixture For Refining Petroleum (AREA)
- Catalysts (AREA)
- Gas Separation By Absorption (AREA)
- Cleaning And De-Greasing Of Metallic Materials By Chemical Methods (AREA)
Description
United States Patent Int. C1. 0611) 6/34 US. Cl. 21--60.5 4 Claims ABSTRACT OF THE DISCLOSURE Protection against decomposition of alkali metal hydride containing liquids by coating a surface thereof with a layer of liquid parafinic hydrocarbon which is substantially immiscible and non-reactive with the alkali metal hydride liquid, has a boiling point at least 20 C. higher than the temperature of the alkali metal hydride containing liquid and has a melting point below the temperature of the alkali metal hydride containing liquid.
This invention relates to a method of preventing the decomposition of metal hydride. It more particularly refers to the prevention of decomposition of liquid mixtures of alkali hydroxides and metal hydrides.
Metal descaling has become an important industrial process. It has been found that one particularly good descalant is a solution of a metal hydride, particularly an alkali metal hydride, in an eutectic or nearly eutectic mixture of metal hydroxides, particularly alkali metal hydroxides. Such descaling solutions are known to the art, see German patent application D 44,165 which corresponds to US. application Ser. No. 451,671, filed Apr. 15, 1965 now abandoned.
These solutions have been used to descale iron, steel and most non-ferrous metals in an efiicient manner. It is unfortunate however that the use of a solution of a metal hydride in a metal hydroxide eutectic or near eutectic for descaling or perhaps any other purpose sufiers from disadvantages having nothing whatever to do with the utility of such solutions as descalants or anything else.
The problem is that metal hydrides are quite reactive with the water content of the air such that the metal hydride decomposes and thus becomes unsuited to the use for which it or its solution was intended. Further, one of the products of decomposition is hydrogen gas which, as is well known, is quite flammable and is explosive in certain proportions in admixture with air. Thus the problem is three-fold: how to prevent metal hydride decomposition; how to prevent hydrogen ignition; and how to prevent explosion of hydrogen-air mixtures.
Various and sundry methods have been conceived to solve these related probelms. Some of the solutions suggested to solve these problems include mechanically covering the vat, trough or other vessel in which the metal hydride solution is maintained, which cover could conceiva'bly be of the same material as is the vessel or could be of another solid material hingedly or removably aflixed to the containing vessel. This proposal has not been partion-larly successful since the cover must be opened each time an article to be descaled or a finished descaled article is inserted into or removed from, respectively the vessel. Upon each opening a certain amount of air is, of necessity, permitted access to the metal hydride solution whereby such hydride can be decomposed or hydrogen decomposition product which was produced during the last previous access is given access to the air whereby an explosive or at least inflammable situation is potentially created.
3,468,621 Patented Sept. 23, 1969 It can be conceived that the surface of the metal hydride solution in metal hydroxide can be constantly swept with an inert gas such as nitrogen or a rare gas, but it must be appreciated that this would be an extremely expensive procedure to add to what is now a relatively inexpensive process whereby it could be debated as to whether it would be cheaper to permit the metal hydride to decompose or to blanket and sweep the solution with inert gas to prevent the decomposition of the metal hydride.
It is thus apparent that no economically practical, workable solution to the problems presented has as yet been found.
It is therefore an object of this invention to provide a method of preventing the decomposition of metal, particularly alkali metal, hydrides.
It is another object of this invention to provide a method of preventing such decomposition at elevated temperatures in a liquid metal hydroxide solution of such metal hydride.
Other and additional objects of this invention will become apparent from a consideration of this entire specification, including the claims appended hereto.
In accord with and fulfilling these objects, this invention resides, in one of its broadest aspects, in providing a liquid coating for a descaling liquid soultion of metal hydride.
Although reference has hereinbefore been made to solutions of metal hydrides in mixtures, particularly eutectic mixtures of metal hydroxides, and although this is one of the preferred embodiments of this invention, the method of this invention is applicable to prevention of decomposition of metal hydrides in general where such metal hydrides have the potentiality of being exposed to air or oxygen. With this in mind, this invention will be further described with respect to the embodiment thereof where metal hydride is dissolved in liquid mixtures of metal hydroxides.
In carrying out this invention, it is necessary for the liquid coating to have certain attributes. Such coating must be substantially immiscible and non-reactive with respect to the metal hydride or other components of the liquid it is coated upon. It must be a liquid at the temperatures of operation, must have a relatively low vapor pressure and flammability at these temperatures and must not decompose to any appreciable extent at these temperatures.
One class of materials, that has been found to be eminently suited to use in this invention possessing substantially all of the attributes required and set forth above, is relatively high molecular weight hydrocarbons, particularly paraflinic materials. These saturated hydrocarbons may be relatively low molecular weight olefin polymers or they may be naturally occurring or synthetic paratfin oils. Exemplary of the naturally occurring oils useful in this invention are crude oil fractions having melting points of about -50 to C. The commercial product Bayol marketed by Esso Standard Oil Company is exemplary of paratfins suited to use in this invention. Also suited are products of Fischer-Tropsch synthesis using cobalt catalysts in the known way. Oligomers and low molecular weight polymers of ethylene having molecular weights of about 3000 to 8000 are suited to use in this invention. Exemplary of the polyethylenes referred to are those marketed by BASF as Lupolen N and by US. Industries as Epolene.
Paraflins, according to this invention, should have boiling points at least about 20 C. higher than the hydride solution operating temperatures and should have melting points at least about 5 C. below such operating tempera ture.
The following examples are given by way of illustration of the invention and are in no way limiting thereon.
3 Example 1 An eutectic melt of sodium hydroxide mixed with potassium hydroxide was prepared containing 2% by weight sodium hydride. About eight (8) tons of this melt were disposed in a vessel such that the surface area of the melt was about five square meters. The bath temperature was brought to 230 C. and held there uncovered for about 48 hours after which time the sodium hydride content of the melt was measured to be 1% by weight.
Example 2 Example 1 was repeated except that the surface of the melt was coated with about 5 millimeters of a white oil having no components which distilled below 300 C. No loss of metal hydride could be determined at the end of the 48 hour period.
What is claimed is:
1. The method of preventing the decomposition of the alkali hydride content of a melt comprising a mixture of alkali metal hydride and alkali metal hydroxide, which comprises coating said melt on the surface thereof which would otherwise be exposed to air, with a liquid layer of a parafiinic hydrocarbon which is substantially immiscible and non-reactive with said alkali metal hydride containing melt, has a boiling point at least about 20 C. higher than the temperature of said alkali metal hydride containing melt and has a melting point below the temperature of said alkali metal hydride containing bath.
2. The method claimed in claim 1, wherein said paraffinic hydrocarbon has a melting point of about to C.
3. The method as claimed in claim 1, wherein said alkali metal is at least one member selected from the group consisting of sodium, potassium and lithium.
4. The method as claimed in claim 1, wherein said melt is a mixture together with sodium hydride of a substantially eutectic mixture of sodium hydroxide and potassium hydroxide.
References Cited UNITED STATES PATENTS 2/ 1956 Carter 1342 X 8/1959 Banus et al. 23-204 US. Cl. X.R.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DED0047235 | 1965-05-12 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| US3468621A true US3468621A (en) | 1969-09-23 |
Family
ID=7050287
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| US548859A Expired - Lifetime US3468621A (en) | 1965-05-12 | 1966-05-10 | Prevention of metal hydride decomposition |
Country Status (6)
| Country | Link |
|---|---|
| US (1) | US3468621A (en) |
| BE (1) | BE680892A (en) |
| DE (1) | DE1546113A1 (en) |
| GB (1) | GB1139201A (en) |
| NL (1) | NL6606450A (en) |
| SE (1) | SE300921B (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20130029054A1 (en) * | 2010-01-11 | 2013-01-31 | Kolene Corporation | Metal surface scale conditioning |
Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US2734036A (en) * | 1956-02-07 | Preventing the formation of carbon | ||
| US2898195A (en) * | 1956-05-31 | 1959-08-04 | Metal Hydrides Inc | Method for preparing sodium hydride |
-
1965
- 1965-05-12 DE DE19651546113 patent/DE1546113A1/en active Pending
-
1966
- 1966-05-10 US US548859A patent/US3468621A/en not_active Expired - Lifetime
- 1966-05-11 NL NL6606450A patent/NL6606450A/xx unknown
- 1966-05-11 GB GB20993/66A patent/GB1139201A/en not_active Expired
- 1966-05-11 SE SE6476/66A patent/SE300921B/xx unknown
- 1966-05-11 BE BE680892D patent/BE680892A/xx unknown
Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US2734036A (en) * | 1956-02-07 | Preventing the formation of carbon | ||
| US2898195A (en) * | 1956-05-31 | 1959-08-04 | Metal Hydrides Inc | Method for preparing sodium hydride |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20130029054A1 (en) * | 2010-01-11 | 2013-01-31 | Kolene Corporation | Metal surface scale conditioning |
| US10006129B2 (en) | 2010-01-11 | 2018-06-26 | Kolene Corporation | Metal surface scale conditioning |
Also Published As
| Publication number | Publication date |
|---|---|
| GB1139201A (en) | 1969-01-08 |
| SE300921B (en) | 1968-05-13 |
| NL6606450A (en) | 1966-11-14 |
| DE1546113A1 (en) | 1970-12-17 |
| BE680892A (en) | 1966-11-14 |
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