CA2049699C - Monohydrogen orthophosphate deicing composition - Google Patents
Monohydrogen orthophosphate deicing composition Download PDFInfo
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- CA2049699C CA2049699C CA 2049699 CA2049699A CA2049699C CA 2049699 C CA2049699 C CA 2049699C CA 2049699 CA2049699 CA 2049699 CA 2049699 A CA2049699 A CA 2049699A CA 2049699 C CA2049699 C CA 2049699C
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- deicing composition
- deicing
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- 239000000203 mixture Substances 0.000 title claims abstract description 83
- NBIIXXVUZAFLBC-UHFFFAOYSA-N Phosphoric acid Chemical compound OP(O)(O)=O NBIIXXVUZAFLBC-UHFFFAOYSA-N 0.000 title claims abstract description 20
- FAPWRFPIFSIZLT-UHFFFAOYSA-M Sodium chloride Chemical compound [Na+].[Cl-] FAPWRFPIFSIZLT-UHFFFAOYSA-M 0.000 claims abstract description 85
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims abstract description 46
- 239000011780 sodium chloride Substances 0.000 claims abstract description 42
- 159000000003 magnesium salts Chemical class 0.000 claims abstract description 19
- 238000000034 method Methods 0.000 claims abstract description 17
- NBIIXXVUZAFLBC-UHFFFAOYSA-K phosphate Chemical compound [O-]P([O-])([O-])=O NBIIXXVUZAFLBC-UHFFFAOYSA-K 0.000 claims abstract description 15
- MNNHAPBLZZVQHP-UHFFFAOYSA-N diammonium hydrogen phosphate Chemical compound [NH4+].[NH4+].OP([O-])([O-])=O MNNHAPBLZZVQHP-UHFFFAOYSA-N 0.000 claims abstract description 10
- MHJAJDCZWVHCPF-UHFFFAOYSA-L dimagnesium phosphate Chemical compound [Mg+2].OP([O-])([O-])=O MHJAJDCZWVHCPF-UHFFFAOYSA-L 0.000 claims abstract description 7
- 229910000397 disodium phosphate Inorganic materials 0.000 claims abstract description 6
- BNIILDVGGAEEIG-UHFFFAOYSA-L disodium hydrogen phosphate Chemical compound [Na+].[Na+].OP([O-])([O-])=O BNIILDVGGAEEIG-UHFFFAOYSA-L 0.000 claims abstract description 5
- 235000019800 disodium phosphate Nutrition 0.000 claims abstract description 5
- 229910000388 diammonium phosphate Inorganic materials 0.000 claims abstract 3
- 235000019838 diammonium phosphate Nutrition 0.000 claims abstract 3
- ZPWVASYFFYYZEW-UHFFFAOYSA-L dipotassium hydrogen phosphate Chemical compound [K+].[K+].OP([O-])([O-])=O ZPWVASYFFYYZEW-UHFFFAOYSA-L 0.000 claims abstract 3
- 229910000396 dipotassium phosphate Inorganic materials 0.000 claims abstract 3
- 235000019797 dipotassium phosphate Nutrition 0.000 claims abstract 3
- 230000007797 corrosion Effects 0.000 claims description 31
- 238000005260 corrosion Methods 0.000 claims description 31
- 229910052751 metal Inorganic materials 0.000 claims description 17
- 239000002184 metal Substances 0.000 claims description 17
- 150000003839 salts Chemical class 0.000 claims description 17
- CWYNVVGOOAEACU-UHFFFAOYSA-N Fe2+ Chemical compound [Fe+2] CWYNVVGOOAEACU-UHFFFAOYSA-N 0.000 claims description 16
- 239000007864 aqueous solution Substances 0.000 claims description 14
- TWRXJAOTZQYOKJ-UHFFFAOYSA-L Magnesium chloride Chemical compound [Mg+2].[Cl-].[Cl-] TWRXJAOTZQYOKJ-UHFFFAOYSA-L 0.000 claims description 10
- 239000003112 inhibitor Substances 0.000 claims description 10
- HEMHJVSKTPXQMS-UHFFFAOYSA-M Sodium hydroxide Chemical compound [OH-].[Na+] HEMHJVSKTPXQMS-UHFFFAOYSA-M 0.000 claims description 9
- 229910052708 sodium Inorganic materials 0.000 claims description 8
- 239000011734 sodium Substances 0.000 claims description 8
- 229910052943 magnesium sulfate Inorganic materials 0.000 claims description 7
- CSNNHWWHGAXBCP-UHFFFAOYSA-L Magnesium sulfate Chemical compound [Mg+2].[O-][S+2]([O-])([O-])[O-] CSNNHWWHGAXBCP-UHFFFAOYSA-L 0.000 claims description 6
- 239000007788 liquid Substances 0.000 claims description 5
- 229910001629 magnesium chloride Inorganic materials 0.000 claims description 5
- 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 claims description 4
- ZLMJMSJWJFRBEC-UHFFFAOYSA-N Potassium Chemical compound [K] ZLMJMSJWJFRBEC-UHFFFAOYSA-N 0.000 claims description 4
- 229910052700 potassium Inorganic materials 0.000 claims description 4
- 239000011591 potassium Substances 0.000 claims description 4
- JLVVSXFLKOJNIY-UHFFFAOYSA-N Magnesium ion Chemical compound [Mg+2] JLVVSXFLKOJNIY-UHFFFAOYSA-N 0.000 claims description 3
- 229910001425 magnesium ion Inorganic materials 0.000 claims description 3
- 235000019341 magnesium sulphate Nutrition 0.000 claims description 3
- 229940085991 phosphate ion Drugs 0.000 claims description 3
- 229910000147 aluminium phosphate Inorganic materials 0.000 claims 4
- CDBYLPFSWZWCQE-UHFFFAOYSA-L Sodium Carbonate Chemical compound [Na+].[Na+].[O-]C([O-])=O CDBYLPFSWZWCQE-UHFFFAOYSA-L 0.000 claims 2
- 235000017550 sodium carbonate Nutrition 0.000 claims 1
- 229910000029 sodium carbonate Inorganic materials 0.000 claims 1
- QGZKDVFQNNGYKY-UHFFFAOYSA-O Ammonium Chemical compound [NH4+] QGZKDVFQNNGYKY-UHFFFAOYSA-O 0.000 abstract description 4
- 229910001413 alkali metal ion Inorganic materials 0.000 abstract description 2
- 239000000243 solution Substances 0.000 description 14
- 229910052783 alkali metal Inorganic materials 0.000 description 7
- 230000000694 effects Effects 0.000 description 7
- -1 alkali metal salts Chemical class 0.000 description 6
- 150000001340 alkali metals Chemical class 0.000 description 6
- OKKJLVBELUTLKV-UHFFFAOYSA-N Methanol Chemical compound OC OKKJLVBELUTLKV-UHFFFAOYSA-N 0.000 description 3
- 239000000654 additive Substances 0.000 description 3
- 239000002585 base Substances 0.000 description 3
- 239000011777 magnesium Substances 0.000 description 3
- 238000002156 mixing Methods 0.000 description 3
- VLKZOEOYAKHREP-UHFFFAOYSA-N n-Hexane Chemical compound CCCCCC VLKZOEOYAKHREP-UHFFFAOYSA-N 0.000 description 3
- UXVMQQNJUSDDNG-UHFFFAOYSA-L Calcium chloride Chemical compound [Cl-].[Cl-].[Ca+2] UXVMQQNJUSDDNG-UHFFFAOYSA-L 0.000 description 2
- VEXZGXHMUGYJMC-UHFFFAOYSA-N Hydrochloric acid Chemical compound Cl VEXZGXHMUGYJMC-UHFFFAOYSA-N 0.000 description 2
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 2
- FYYHWMGAXLPEAU-UHFFFAOYSA-N Magnesium Chemical compound [Mg] FYYHWMGAXLPEAU-UHFFFAOYSA-N 0.000 description 2
- 229910000831 Steel Inorganic materials 0.000 description 2
- 239000001110 calcium chloride Substances 0.000 description 2
- 229910001628 calcium chloride Inorganic materials 0.000 description 2
- 230000007613 environmental effect Effects 0.000 description 2
- 230000036571 hydration Effects 0.000 description 2
- 238000006703 hydration reaction Methods 0.000 description 2
- 230000002401 inhibitory effect Effects 0.000 description 2
- 229910052749 magnesium Inorganic materials 0.000 description 2
- 239000010959 steel Substances 0.000 description 2
- 239000004094 surface-active agent Substances 0.000 description 2
- 239000003643 water by type Substances 0.000 description 2
- BHPQYMZQTOCNFJ-UHFFFAOYSA-N Calcium cation Chemical compound [Ca+2] BHPQYMZQTOCNFJ-UHFFFAOYSA-N 0.000 description 1
- 229910000975 Carbon steel Inorganic materials 0.000 description 1
- VEXZGXHMUGYJMC-UHFFFAOYSA-M Chloride anion Chemical compound [Cl-] VEXZGXHMUGYJMC-UHFFFAOYSA-M 0.000 description 1
- 229910000640 Fe alloy Inorganic materials 0.000 description 1
- YZCKVEUIGOORGS-UHFFFAOYSA-N Hydrogen atom Chemical compound [H] YZCKVEUIGOORGS-UHFFFAOYSA-N 0.000 description 1
- 229910019142 PO4 Inorganic materials 0.000 description 1
- 229920000388 Polyphosphate Polymers 0.000 description 1
- 108091006629 SLC13A2 Proteins 0.000 description 1
- HCHKCACWOHOZIP-UHFFFAOYSA-N Zinc Chemical compound [Zn] HCHKCACWOHOZIP-UHFFFAOYSA-N 0.000 description 1
- 239000002253 acid Substances 0.000 description 1
- 150000001412 amines Chemical class 0.000 description 1
- LFVGISIMTYGQHF-UHFFFAOYSA-N ammonium dihydrogen phosphate Chemical compound [NH4+].OP(O)([O-])=O LFVGISIMTYGQHF-UHFFFAOYSA-N 0.000 description 1
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 1
- 239000012267 brine Substances 0.000 description 1
- 229910001424 calcium ion Inorganic materials 0.000 description 1
- 239000010962 carbon steel Substances 0.000 description 1
- 150000001875 compounds Chemical class 0.000 description 1
- 230000002939 deleterious effect Effects 0.000 description 1
- 238000001035 drying Methods 0.000 description 1
- 238000007654 immersion Methods 0.000 description 1
- 230000005764 inhibitory process Effects 0.000 description 1
- 229910052742 iron Inorganic materials 0.000 description 1
- JEIPFZHSYJVQDO-UHFFFAOYSA-N iron(III) oxide Inorganic materials O=[Fe]O[Fe]=O JEIPFZHSYJVQDO-UHFFFAOYSA-N 0.000 description 1
- 229910000021 magnesium carbonate Inorganic materials 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 239000000155 melt Substances 0.000 description 1
- 150000002739 metals Chemical class 0.000 description 1
- 238000006386 neutralization reaction Methods 0.000 description 1
- 230000003647 oxidation Effects 0.000 description 1
- 238000007254 oxidation reaction Methods 0.000 description 1
- 230000001590 oxidative effect Effects 0.000 description 1
- 229910052760 oxygen Inorganic materials 0.000 description 1
- 239000001301 oxygen Substances 0.000 description 1
- 239000010452 phosphate Substances 0.000 description 1
- 229940045916 polymetaphosphate Drugs 0.000 description 1
- 239000001205 polyphosphate Substances 0.000 description 1
- 235000011176 polyphosphates Nutrition 0.000 description 1
- 239000002243 precursor Substances 0.000 description 1
- 239000004576 sand Substances 0.000 description 1
- 239000001488 sodium phosphate Substances 0.000 description 1
- HPALAKNZSZLMCH-UHFFFAOYSA-M sodium;chloride;hydrate Chemical compound O.[Na+].[Cl-] HPALAKNZSZLMCH-UHFFFAOYSA-M 0.000 description 1
- 239000008247 solid mixture Substances 0.000 description 1
- 229910052725 zinc Inorganic materials 0.000 description 1
- 239000011701 zinc Substances 0.000 description 1
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- Detergent Compositions (AREA)
- Preventing Corrosion Or Incrustation Of Metals (AREA)
Abstract
A deicing composition which includes NaCl and an orthophosphate selected from the group consisting of MgHPO4, Na2HPO4, K2HPO4, (NH4)2HPO4, hydrated forms thereof and mixtures thereof. When the monohydrogen orthophosphate has the alkali metal ions or ammonium cation, the deicing composition includes a water soluble magnesium salt. A method of deicing using the deicing composition also is described.
Description
.g.
A Pd9~NOHYI)ROCEN ~R'1'IIOPIIOSPIIATE DEICING COMPCSTfION
' the ~nven'tion Field of The present invention is directed to a deicing composition and a method for utilizing the deicing composition. More particularly, the present invention is directed to a deicing composition which comprises the deicer salt NaCl and a corrosion inhibitor which includes magnesium, sodium, potassium or ammonium monohydrogen orthophosphate (MgHP04, NaZHP04, KZHP04 or (NH4)ZHP04) , and if the alkali metal or ammonium orthophosphate is used, the composition includes a water soluble magnesium salt.
BsckQround of the ynvention Calcium chloride and alkali metal salts, such as sodium chloride, are extensively used in very large quantities on the roads of many countries for snow and ice removal. The use of calcium chloride or sodium chloride has, however, met with some resistance due to their corrosive effect on ferrous metal and deleterious effect on concrete. Indeed data has been released suggesting that the cost of the damage associated with the widespread application of salt is approximately fourteen times the direct cost associated with the application of the salt: D. M. Murray, et al., An Economic Analysis of the Environmental Impact of Highway Deicing, U.S. Environmental Protection Agency, Cincinnati, Ohio, EPA-600/A-76-105 (May 1976).
Accordingly, it would be highly desirable to provide a deicing composition which deices rapidly, has a reduced level of concrete damage such as by scaling the surface of the concrete, and reduces corrosion of ferrous metallic objects.
A Pd9~NOHYI)ROCEN ~R'1'IIOPIIOSPIIATE DEICING COMPCSTfION
' the ~nven'tion Field of The present invention is directed to a deicing composition and a method for utilizing the deicing composition. More particularly, the present invention is directed to a deicing composition which comprises the deicer salt NaCl and a corrosion inhibitor which includes magnesium, sodium, potassium or ammonium monohydrogen orthophosphate (MgHP04, NaZHP04, KZHP04 or (NH4)ZHP04) , and if the alkali metal or ammonium orthophosphate is used, the composition includes a water soluble magnesium salt.
BsckQround of the ynvention Calcium chloride and alkali metal salts, such as sodium chloride, are extensively used in very large quantities on the roads of many countries for snow and ice removal. The use of calcium chloride or sodium chloride has, however, met with some resistance due to their corrosive effect on ferrous metal and deleterious effect on concrete. Indeed data has been released suggesting that the cost of the damage associated with the widespread application of salt is approximately fourteen times the direct cost associated with the application of the salt: D. M. Murray, et al., An Economic Analysis of the Environmental Impact of Highway Deicing, U.S. Environmental Protection Agency, Cincinnati, Ohio, EPA-600/A-76-105 (May 1976).
Accordingly, it would be highly desirable to provide a deicing composition which deices rapidly, has a reduced level of concrete damage such as by scaling the surface of the concrete, and reduces corrosion of ferrous metallic objects.
-2~
Various additives have been proposed for mixing with salt to aid in inhibiting corrosion caused by the salt. British Patent No. 128509 to Bisriop et al.
describes a composition suitable for use in the inhibition of corrosion caused by salt, which includes a water soluble polyphosphate and a surface active agent.
The surface active agent is various amine compounds, In an article by E. E. Steed, Road Research.Laboratory, Ministry of Transport, UK Report LR268-1969, polymetaphosphate inhibitors which require the presence of calcium ions are described to be effective as a corrosion inhibitor for brine solutions.
There is a serious need to provide a low cost deicing composition which reduces oxidative corrosion caused by aqueous solutions of NaCl. Depending on cost, a deicing composition which reduces such corrosion ar rust would be highly desirable for use on roadways where large quantities of the deicing composition are required.
The present invention i.s directed to providing a corrosion resistant, loW GOSt, deicing composition which is suitable for highway and sidewalk use.
Accordingly, one of the principle objects of the invention is to provide a deicing composition which deices rapidly. Another object of this invention is to provide a deicing composition which causes a reduced level of corrosion to ferrous metal. Yet another important object of this invention is to provide a deicing composition which utilizes NaCl as a cost effective deicer, but reduce the highly corrosive effect of NaCl on ferrous metal.
These and other objects of the invention will become apparent from the following description.
A'I°TORNEY DCDCKET
NO. 51853 swn~nary of the Invention Orthophosphates tend to form slightly soluble compounds with magnesium salts and may not be expected to perform well together as corrosion inhibiting composi°
tions. Surprisingly, this invention combines NaCl and the orthophosphates selected from the group consisting of MgHP04, Na2HP04, KZHP04, or (NH4) ZHP04 which may be in the hydrated form, to produce an effective anticorrosive/
antiscaling deicer composition which provides new and unexpected anticorrosive activity over other deicing compositions.
The present invention is directed to a non liquid or dry deicing composition comprising NaCI as a deicer salt in an amount effective for deicing a surface with frozen water there-on, and an amount of orthophosphate selected from the group consisting of MgHPO~, NaZHP04, KZHP04, (NH4) ZHP04, hydrated forms thereof and mixtures thereof effective for the reduction of corrosion of ferrous metal by aqueous solutions of NaCl.
When the monohydrogen salt has the alkali metal ions sodium or potassium or the ammonium cation, the deicing composition includes a water soluble salt of magnesium, such as MgCl2 or MgS04, in an amount effective to aid the ammonium or alkali metal monohy°drogen phosphate in reducing the corrosion of ferrous metal by aqueous solutions of NaCl. In this aspect of the invention, the water soluble magnesium salt provides for reduced corrosion of ferrous metal and except in the case of the ammonium cation, reduces the scaling that NaCl causes on concrete. However, additional metals such as zinc or other additives such as amines are not required to provide a composition which has effective anticorrosive properties.
The present invention is also directed to a method for deicing a surface having frozen water thereon IAlO 5153 _q_ by applying the deicing composition of the invention onto the surface of the ice.
Detailed Deserintion of the Invention As used herein "monohydrogen orthophosphate"
means orthophosphates selected from the group consisting of MgHP04, NazHP04 I~zHP04, (NH4) ZHPO~ and mixtures thereof .
These orthophosphates may be in their hydrated form, such as MgHP04~3H20, where there generally will be from about 1 to about 3 waters of hydration, or sodium hydrogen phosphate which has up to 12 waters of hydration.
As used herein "ferrous metal" means iron or alloys of iron including steel which undergo corrosion or oxidation under ambient conditions.
As used herein water soluble salt means a water solubility of at least about 10 g/1 at 30° C.
According to the invention, the alkali metal or ammonium monohydrogen orthophosphate used in combination with a water soluble magnesium salt reduces the corrosive effect on ferrous metal that is usually associated with aqueous solutions of NaCl or, magnesium monohydrogen orthophosphate reduces the corrosive effect on ferrous metal that is usually associated with aqueous solutions of NaCl.
The deicing composition comprises NaCl and a corrosion inhibitor selected from the group consisting of MgHPO4, an alkali metal or ammonium monohydrogen orthophosphate in combination with a water soluble magnesium salt and mixtures thereof, where the corrosion inhibitor is in an amount effective to reduce the corrosive effect on metal of aqueous solutions of NaCl.
The effective ratio of the orthophosphate to NaCl can vary widely. The deicing composition of the invention contains at least about 1.0 weight %, arid preferably from about 2 to about 10 weight %, based upon ~;~1~~~4i~~
ATTORNEY DOCKE~l NO. 51853 .5.
the weight of the deicing composition on a dry basis, of monohydrogen orthophosphate in combination with about 90 weight percent and preferably from about 90% to about 9S
weight ~, based upon the weight of the composition on a dry basis, of NaCI. Due to its low cost, sodium chloride is in the major amount of the deicing composition, such as about 95 weight percent of the deicing composition, with the monohydrogen orthophosphate being present in an amount effective to reduce the rate of corrosion of ferrous metal and/or scaling of concrete by aqueous solutions of deicer salts.
The monohydrogen orthophosphate may be made by the neutralization of phosphoric or superphosphoric acid and water with a base or base precursor such as NaOH, NazC03, Mg (OH) 2, MgC03 or Mg0 to a pH of about 7. In this aspect the acid is neutralized with the base to a pH in the range of from about 5 to about 9 yielding the water soluble orthophosphate salt and water. Water soluble magnesium salts such as magnesium sulfate (MgS04~7H20) or magnesium chloride may be combined with the alkali metal or ammonium monohydrogen orthophosphate such as disodium phosphate (NazHPO4) with large excesses of NaCl to provide the deicing composition of the invention, which in this aspect of the invention is MgHP04~3Hz0 + Na2S0G + NaCI.
One or more water soluble magnesium salts such as MgCl2 ~ XHzO and MgS04 ~ YH20 where X = 0 to 6 and Y = 0 to 7 are added to the corrision inhibitor which includes the alkali metal or ammonium monohydrogen orthophosphate in an amount effective to aid the orthophosphate to reduce corrosion of the highly corrosive NaCl. These magnesium salts may be used alone or in combination, but their total amount should not exceed about 9 weight percent of the deicing composition and should not replace the orthophosphate such that it goes below 1.0 weight percent or NaC1 such that it goes below about 90 weight percent.
ATTORNEY DOCKET
NO. 51853 For best results the amount of magnesium ion should be in a molar amount that is about equal to the amount of phosphate ion provided by aqueous solutions of the deicing compositions. The deicing composition of the invention is provided by blending the NaCl and water soluble monohydrogen orthophosphate and other additives in the desired weight ratio and blending them until a substantially homageneous solid mixture is obtained.
The deicing composition of the invention is applied to a structure coated with ice or snow by any suitable means, such as by mechanical spreading. The deicing composition of the invention melts ice at about the rate of pure NaCl, but protects ferrous metal from the corrosive effects of NaCl. The deicing composition of the present invention can also be combined with conventional materials intended to increase traction, such as sand, gravel, and the like.
The following examples further illustrate various features of the present invention but are intended to in no way limit the scope of the invention which is set forth in the appended claims.
EX~IMPhE ~
The corrosivity of various deicers was measured by an alternate immersion corrosion test involving the use of 2" x 3" S.A.E. 1010 carbon steel panels which were degreased in hexane and dried after a methanol rinse. The steel panels had a 1/4" diameter hole drilled in the center and near the top of the 2'° side.
The panels had numbers stamped in each of them. All panels were weighed to the nearest tenth of a milligram after drying. Three percent by dry weight basis of deicer solutions were prepared in all cases except for plain water. Four panels were suspended by a rod pushed through the 1/4" holes and separated by segments of .7.
rubber tubing. Each assembly was suspended in the water or 3% deicer solutions such that the panels were 1/2 immersed. During two 1 hour periods each work day the panels.were suspended in air to achieve good contact with oxygen. The other 22 hours of each work day the panels were 1/2 immersed. Over weekends, panels were 1/2 immersed. At the end of each week, old solution was removed and replaced with new solution of the same type.
At the end of one month the panels were removed and the solutions cleaned with 1820 g hot water, 180 g of concentrated hydrochloric acid and 2 g of Rodine 213.
The panels were weighed and the percent protection against salt induced corrosion was calculated as follows:
IS % Protection !lgainst Salt* Induced Cbrrosion = 100 x m ~w Avg Wt Loss in Test Sol~n-Avg~ Wt Loss in Water-Avg Cleaniy Wt Loss Avg Wt Loss in Salt 601 ~ n-Avg Wt Ipss i.n Water'Avg Clear~i.x~g Wt Ives Average P~eroent Protection Weight l~gainst 3% Solution Loss Salt Induced Corrosion ?5 Water 0.4744 100.0 3% solution of sodium chloride 0.9567 0.0 30 3% solution of 98.0% NaCl 2 . 0$ ~HPO' ~ 3Iiz0 0. 0174 194 . 8 35 3% solution of 95.6% NaCl 2 . 8% MgS04 ~ 7Fi20 1.6% Na~04 0.0182 194.6 40 3% solution of 93 .77% NaCl 3.23% ~?.I-L~O
3.00% Na~4 0.4093 15.6 A7TORNE'Y SOCKET
IdO. 51$53 .g.
3% solution of 96.1% NaCL
2.0% Na~04 1.9% f~Cl2~Hz0 0.0145 195.4 3% solution of 94.8% NaCl 5.2% rig~0~~3I-i~0 0.0116 196.0 3% solution of 96.1% NaCl 2.0% Na~04 1.97% MgCi2°2I-i~0 0.0145 195.4 * As us~l in the sales "salt" means sodi~n chloride.
Various additives have been proposed for mixing with salt to aid in inhibiting corrosion caused by the salt. British Patent No. 128509 to Bisriop et al.
describes a composition suitable for use in the inhibition of corrosion caused by salt, which includes a water soluble polyphosphate and a surface active agent.
The surface active agent is various amine compounds, In an article by E. E. Steed, Road Research.Laboratory, Ministry of Transport, UK Report LR268-1969, polymetaphosphate inhibitors which require the presence of calcium ions are described to be effective as a corrosion inhibitor for brine solutions.
There is a serious need to provide a low cost deicing composition which reduces oxidative corrosion caused by aqueous solutions of NaCl. Depending on cost, a deicing composition which reduces such corrosion ar rust would be highly desirable for use on roadways where large quantities of the deicing composition are required.
The present invention i.s directed to providing a corrosion resistant, loW GOSt, deicing composition which is suitable for highway and sidewalk use.
Accordingly, one of the principle objects of the invention is to provide a deicing composition which deices rapidly. Another object of this invention is to provide a deicing composition which causes a reduced level of corrosion to ferrous metal. Yet another important object of this invention is to provide a deicing composition which utilizes NaCl as a cost effective deicer, but reduce the highly corrosive effect of NaCl on ferrous metal.
These and other objects of the invention will become apparent from the following description.
A'I°TORNEY DCDCKET
NO. 51853 swn~nary of the Invention Orthophosphates tend to form slightly soluble compounds with magnesium salts and may not be expected to perform well together as corrosion inhibiting composi°
tions. Surprisingly, this invention combines NaCl and the orthophosphates selected from the group consisting of MgHP04, Na2HP04, KZHP04, or (NH4) ZHP04 which may be in the hydrated form, to produce an effective anticorrosive/
antiscaling deicer composition which provides new and unexpected anticorrosive activity over other deicing compositions.
The present invention is directed to a non liquid or dry deicing composition comprising NaCI as a deicer salt in an amount effective for deicing a surface with frozen water there-on, and an amount of orthophosphate selected from the group consisting of MgHPO~, NaZHP04, KZHP04, (NH4) ZHP04, hydrated forms thereof and mixtures thereof effective for the reduction of corrosion of ferrous metal by aqueous solutions of NaCl.
When the monohydrogen salt has the alkali metal ions sodium or potassium or the ammonium cation, the deicing composition includes a water soluble salt of magnesium, such as MgCl2 or MgS04, in an amount effective to aid the ammonium or alkali metal monohy°drogen phosphate in reducing the corrosion of ferrous metal by aqueous solutions of NaCl. In this aspect of the invention, the water soluble magnesium salt provides for reduced corrosion of ferrous metal and except in the case of the ammonium cation, reduces the scaling that NaCl causes on concrete. However, additional metals such as zinc or other additives such as amines are not required to provide a composition which has effective anticorrosive properties.
The present invention is also directed to a method for deicing a surface having frozen water thereon IAlO 5153 _q_ by applying the deicing composition of the invention onto the surface of the ice.
Detailed Deserintion of the Invention As used herein "monohydrogen orthophosphate"
means orthophosphates selected from the group consisting of MgHP04, NazHP04 I~zHP04, (NH4) ZHPO~ and mixtures thereof .
These orthophosphates may be in their hydrated form, such as MgHP04~3H20, where there generally will be from about 1 to about 3 waters of hydration, or sodium hydrogen phosphate which has up to 12 waters of hydration.
As used herein "ferrous metal" means iron or alloys of iron including steel which undergo corrosion or oxidation under ambient conditions.
As used herein water soluble salt means a water solubility of at least about 10 g/1 at 30° C.
According to the invention, the alkali metal or ammonium monohydrogen orthophosphate used in combination with a water soluble magnesium salt reduces the corrosive effect on ferrous metal that is usually associated with aqueous solutions of NaCl or, magnesium monohydrogen orthophosphate reduces the corrosive effect on ferrous metal that is usually associated with aqueous solutions of NaCl.
The deicing composition comprises NaCl and a corrosion inhibitor selected from the group consisting of MgHPO4, an alkali metal or ammonium monohydrogen orthophosphate in combination with a water soluble magnesium salt and mixtures thereof, where the corrosion inhibitor is in an amount effective to reduce the corrosive effect on metal of aqueous solutions of NaCl.
The effective ratio of the orthophosphate to NaCl can vary widely. The deicing composition of the invention contains at least about 1.0 weight %, arid preferably from about 2 to about 10 weight %, based upon ~;~1~~~4i~~
ATTORNEY DOCKE~l NO. 51853 .5.
the weight of the deicing composition on a dry basis, of monohydrogen orthophosphate in combination with about 90 weight percent and preferably from about 90% to about 9S
weight ~, based upon the weight of the composition on a dry basis, of NaCI. Due to its low cost, sodium chloride is in the major amount of the deicing composition, such as about 95 weight percent of the deicing composition, with the monohydrogen orthophosphate being present in an amount effective to reduce the rate of corrosion of ferrous metal and/or scaling of concrete by aqueous solutions of deicer salts.
The monohydrogen orthophosphate may be made by the neutralization of phosphoric or superphosphoric acid and water with a base or base precursor such as NaOH, NazC03, Mg (OH) 2, MgC03 or Mg0 to a pH of about 7. In this aspect the acid is neutralized with the base to a pH in the range of from about 5 to about 9 yielding the water soluble orthophosphate salt and water. Water soluble magnesium salts such as magnesium sulfate (MgS04~7H20) or magnesium chloride may be combined with the alkali metal or ammonium monohydrogen orthophosphate such as disodium phosphate (NazHPO4) with large excesses of NaCl to provide the deicing composition of the invention, which in this aspect of the invention is MgHP04~3Hz0 + Na2S0G + NaCI.
One or more water soluble magnesium salts such as MgCl2 ~ XHzO and MgS04 ~ YH20 where X = 0 to 6 and Y = 0 to 7 are added to the corrision inhibitor which includes the alkali metal or ammonium monohydrogen orthophosphate in an amount effective to aid the orthophosphate to reduce corrosion of the highly corrosive NaCl. These magnesium salts may be used alone or in combination, but their total amount should not exceed about 9 weight percent of the deicing composition and should not replace the orthophosphate such that it goes below 1.0 weight percent or NaC1 such that it goes below about 90 weight percent.
ATTORNEY DOCKET
NO. 51853 For best results the amount of magnesium ion should be in a molar amount that is about equal to the amount of phosphate ion provided by aqueous solutions of the deicing compositions. The deicing composition of the invention is provided by blending the NaCl and water soluble monohydrogen orthophosphate and other additives in the desired weight ratio and blending them until a substantially homageneous solid mixture is obtained.
The deicing composition of the invention is applied to a structure coated with ice or snow by any suitable means, such as by mechanical spreading. The deicing composition of the invention melts ice at about the rate of pure NaCl, but protects ferrous metal from the corrosive effects of NaCl. The deicing composition of the present invention can also be combined with conventional materials intended to increase traction, such as sand, gravel, and the like.
The following examples further illustrate various features of the present invention but are intended to in no way limit the scope of the invention which is set forth in the appended claims.
EX~IMPhE ~
The corrosivity of various deicers was measured by an alternate immersion corrosion test involving the use of 2" x 3" S.A.E. 1010 carbon steel panels which were degreased in hexane and dried after a methanol rinse. The steel panels had a 1/4" diameter hole drilled in the center and near the top of the 2'° side.
The panels had numbers stamped in each of them. All panels were weighed to the nearest tenth of a milligram after drying. Three percent by dry weight basis of deicer solutions were prepared in all cases except for plain water. Four panels were suspended by a rod pushed through the 1/4" holes and separated by segments of .7.
rubber tubing. Each assembly was suspended in the water or 3% deicer solutions such that the panels were 1/2 immersed. During two 1 hour periods each work day the panels.were suspended in air to achieve good contact with oxygen. The other 22 hours of each work day the panels were 1/2 immersed. Over weekends, panels were 1/2 immersed. At the end of each week, old solution was removed and replaced with new solution of the same type.
At the end of one month the panels were removed and the solutions cleaned with 1820 g hot water, 180 g of concentrated hydrochloric acid and 2 g of Rodine 213.
The panels were weighed and the percent protection against salt induced corrosion was calculated as follows:
IS % Protection !lgainst Salt* Induced Cbrrosion = 100 x m ~w Avg Wt Loss in Test Sol~n-Avg~ Wt Loss in Water-Avg Cleaniy Wt Loss Avg Wt Loss in Salt 601 ~ n-Avg Wt Ipss i.n Water'Avg Clear~i.x~g Wt Ives Average P~eroent Protection Weight l~gainst 3% Solution Loss Salt Induced Corrosion ?5 Water 0.4744 100.0 3% solution of sodium chloride 0.9567 0.0 30 3% solution of 98.0% NaCl 2 . 0$ ~HPO' ~ 3Iiz0 0. 0174 194 . 8 35 3% solution of 95.6% NaCl 2 . 8% MgS04 ~ 7Fi20 1.6% Na~04 0.0182 194.6 40 3% solution of 93 .77% NaCl 3.23% ~?.I-L~O
3.00% Na~4 0.4093 15.6 A7TORNE'Y SOCKET
IdO. 51$53 .g.
3% solution of 96.1% NaCL
2.0% Na~04 1.9% f~Cl2~Hz0 0.0145 195.4 3% solution of 94.8% NaCl 5.2% rig~0~~3I-i~0 0.0116 196.0 3% solution of 96.1% NaCl 2.0% Na~04 1.97% MgCi2°2I-i~0 0.0145 195.4 * As us~l in the sales "salt" means sodi~n chloride.
Claims (25)
1. A non-liquid deicing composition comprising at least about 90 weight percent NaCl; from about 1 to about 10 weight percent of a monohydrogen orthophosphate corrosion inhibitor to reduce the corrosion of ferrous metal by an aqueous solution of NaCl; and a water soluble magnesium salt, wherein the monohydrogen orthophosphate corrosion inhibitor is selected from the group consisting of Na2HPO4 or hydrated forms thereof, K2HPO4 or hydrated forms thereof, (NH4)2HPO4, or hydrated forms thereof and mixtures thereof and wherein the water soluble magnesium salt is in an amount effective to aid the sodium, potassium or ammonium monohydrogen orthophosphate in reducing corrosion by NaCl.
2. A deicing composition as recited in claim 1 wherein the orthophosphate is phosphoric acid neutralized with a base to a pH in the range of from about 5 to about 9.
3. A deicing composition as recited in claim 1 wherein the water soluble magnesium salt comprises not more than about 9 weight percent of the deicing composition.
4. A deicing composition as recited in claim 2 wherein the salt of phosphoric acid is neutralized with a base selected from the group consisting of NaOH, Na2CO3 and mixtures thereof.
5. A deicing composition as recited in claim 3 wherein the water soluble magnesium salt is present in an amount to provide magnesium ion in a molar amount which is about equal to the amount of phosphate ion provided by aqueous solutions of the deicing composition.
6. A deicing composition as recited in claims 1, 3 or wherein the water soluble magnesium salt is selected from the group consisting of MgCl2.cndot.XH2O, MgSO4.cndot.YH2O and mixtures thereof wherein X = 0 to 6 and Y = 0 to 7.
7. A method for deicing a surface having frozen water thereon, said method comprising applying the deicing composition recited in claims 1, 3 or 5 to a surface with frozen water thereon.
8. A method for deicing a surface having frozen water thereon, said method comprising applying the deicing composition recited in claim 2, to a surface with frozen water thereon.
9. A method for deicing a surface having frozen water thereon, said method comprising applying the deicing composition recited in claim 6 to a surface with frozen water thereon.
10. A non-liquid deicing composition comprising at least about 90 weight percent NaCl and from about 1 to about 10 weight percent of MgHPO4 or hydrated forms thereof to reduce the corrosion of ferrous metal by an aqueous solution of NaCl.
11. A deicing composition as recited in claim 10 wherein the NaCl comprises from about 90 to 98 weight percent cf tree deicing composition and the MgHPO4 comprises about 2 to about 10 weight percent of the deicing composition.
12. A method for deicing a surface having frozen water thereon, said method comprising applying the deicing composition recited in claims 10, 11 or 12 to a surface with frozen water thereon.
13. A non-liquid deicing composition consisting essentially of NaCl in an amount effective for deicing; a water soluble magnesium salt; and a monohydrogen orthophosphate corrosion inhibitor in an amount effective for the reduction of corrosion of ferrous metal by an aqueous solution of NaCl, wherein the monohydrogen orthophosphate corrosion inhibitor is selected from the group consisting of Na2HPO4 or hydrated forms thereof, K2HPO4 or hydrated forms thereof, (NH4)2HPO4 or hydrated forms thereof, and mixtures thereof and wherein the water soluble magnesium salt is in an amount effective to aid the sodium, potassium or ammonium monohydrogen orthophosphate in reducing corrosion by NaCl.
14. A deicing composition as recited in claim 13 wherein the orthophosphate is phosphoric acid neutralized with a base to a pH in the range of from about 5 to about 9.
15. A deicing composition as recited in claim 13 wherein the water soluble magnesium salt comprises not more than about 9 weight percent of the deicing composition.
16. A deicing composition as recited in claim 14 wherein the salt or phosphoric acid is neutralized with a base selected from the group consisting of NaOH and mixtures thereof.
17. A deicing composition as recited in claim 15 wherein the water soluble magnesium salt is present in an amount to provide magnesium ion in a molar amount which is about equal to the amount of phosphate ion provided by aqueous solutions of the deicing composition.
18. A deicing composition as recited in claim 13 wherein the NaCl comprises from about 90 to about 98 weight percent of the deicing composition and the orthophosphate comprises about 2 to about 10 weight percent of the deicing composition.
19. A method for deicing a surface having frozen water thereon, said method comprising applying the deicing composition recited in claims 13, 14 or 15 to a surface with frozen water thereon.
20. A non-liquid deicing composition consisting essentially of NaCl in an amount effective for deicing and MgHPO4 or hydrated forms thereof in an amount effective for the reduction of corrosion of ferrous metal by an aqueous solution of NaCl.
21. A deicing composition as recited in claim 20 wherein the sodium chloride comprises at least about 90 weight percent of the deicing composition and the MgHPO4 comprises about 1 to about 10 weight percent of the deicing composition.
22. A deicing composition as recited in claim 20 wherein the NaCl comprises from about 90 to about 98 weight percent of the deicing composition and the orthophosphate comprises about 2 to about 10 weight percent of the deicing composition.
23. A method for deicing a surface having frozen water thereon, said method comprising applying the deicing composition recited in claims 20, 21 or 22 to a surface with frozen water thereon.
24. A deicing composition as recited in claims 13 or 20 wherein the water soluble magnesium salt is selected from the group consisting of MgCl2.cndot.XH2O, MgSO4.cndot.YH2O and mixtures thereof wherein X = 0 to 6 and Y = 0 to 7.
25. A method for deicing a surface having frozen water thereon, said method comprising applying the deicing composition recited in claim 24 to a surface with frozen water thereon.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US57217490A | 1990-08-23 | 1990-08-23 | |
| US572,174 | 1990-08-23 |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CA2049699A1 CA2049699A1 (en) | 1992-02-24 |
| CA2049699C true CA2049699C (en) | 2006-10-31 |
Family
ID=24286671
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA 2049699 Expired - Lifetime CA2049699C (en) | 1990-08-23 | 1991-08-22 | Monohydrogen orthophosphate deicing composition |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA2049699C (en) |
-
1991
- 1991-08-22 CA CA 2049699 patent/CA2049699C/en not_active Expired - Lifetime
Also Published As
| Publication number | Publication date |
|---|---|
| CA2049699A1 (en) | 1992-02-24 |
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