US2004689A - Melting and/or refining of magnesium and magnesium alloys prior to casting, and fluxtherefor - Google Patents
Melting and/or refining of magnesium and magnesium alloys prior to casting, and fluxtherefor Download PDFInfo
- Publication number
- US2004689A US2004689A US745044A US74504434A US2004689A US 2004689 A US2004689 A US 2004689A US 745044 A US745044 A US 745044A US 74504434 A US74504434 A US 74504434A US 2004689 A US2004689 A US 2004689A
- Authority
- US
- United States
- Prior art keywords
- magnesium
- metal
- flux
- melting
- refining
- 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
- FYYHWMGAXLPEAU-UHFFFAOYSA-N Magnesium Chemical compound [Mg] FYYHWMGAXLPEAU-UHFFFAOYSA-N 0.000 title description 27
- 230000008018 melting Effects 0.000 title description 25
- 238000002844 melting Methods 0.000 title description 25
- 229910052749 magnesium Inorganic materials 0.000 title description 16
- 239000011777 magnesium Substances 0.000 title description 16
- 238000007670 refining Methods 0.000 title description 14
- 238000005266 casting Methods 0.000 title description 6
- 229910000861 Mg alloy Inorganic materials 0.000 title description 4
- 230000004907 flux Effects 0.000 description 46
- 229910052751 metal Inorganic materials 0.000 description 45
- 239000002184 metal Substances 0.000 description 45
- TWRXJAOTZQYOKJ-UHFFFAOYSA-L Magnesium chloride Chemical compound [Mg+2].[Cl-].[Cl-] TWRXJAOTZQYOKJ-UHFFFAOYSA-L 0.000 description 15
- 229940091250 magnesium supplement Drugs 0.000 description 15
- 238000000034 method Methods 0.000 description 10
- ORUIBWPALBXDOA-UHFFFAOYSA-L magnesium fluoride Chemical compound [F-].[F-].[Mg+2] ORUIBWPALBXDOA-UHFFFAOYSA-L 0.000 description 8
- 229910001635 magnesium fluoride Inorganic materials 0.000 description 8
- 229910045601 alloy Inorganic materials 0.000 description 7
- 239000000956 alloy Substances 0.000 description 7
- 239000000463 material Substances 0.000 description 5
- 239000000155 melt Substances 0.000 description 5
- 239000000203 mixture Substances 0.000 description 5
- 238000010438 heat treatment Methods 0.000 description 4
- 238000000926 separation method Methods 0.000 description 4
- 229960002337 magnesium chloride Drugs 0.000 description 3
- 235000011147 magnesium chloride Nutrition 0.000 description 3
- 229910001629 magnesium chloride Inorganic materials 0.000 description 3
- 230000003647 oxidation Effects 0.000 description 3
- 238000007254 oxidation reaction Methods 0.000 description 3
- FAPWRFPIFSIZLT-UHFFFAOYSA-M Sodium chloride Chemical compound [Na+].[Cl-] FAPWRFPIFSIZLT-UHFFFAOYSA-M 0.000 description 2
- 239000003795 chemical substances by application Substances 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 239000012535 impurity Substances 0.000 description 2
- 238000002360 preparation method Methods 0.000 description 2
- 238000003756 stirring Methods 0.000 description 2
- 229910001018 Cast iron Inorganic materials 0.000 description 1
- VEXZGXHMUGYJMC-UHFFFAOYSA-M Chloride anion Chemical compound [Cl-] VEXZGXHMUGYJMC-UHFFFAOYSA-M 0.000 description 1
- 241000212342 Sium Species 0.000 description 1
- 229910000831 Steel Inorganic materials 0.000 description 1
- 239000000470 constituent Substances 0.000 description 1
- 239000000374 eutectic mixture Substances 0.000 description 1
- 230000004927 fusion Effects 0.000 description 1
- 230000005484 gravity Effects 0.000 description 1
- 239000008240 homogeneous mixture Substances 0.000 description 1
- 239000011872 intimate mixture Substances 0.000 description 1
- 239000007788 liquid Substances 0.000 description 1
- PALNZFJYSCMLBK-UHFFFAOYSA-K magnesium;potassium;trichloride;hexahydrate Chemical compound O.O.O.O.O.O.[Mg+2].[Cl-].[Cl-].[Cl-].[K+] PALNZFJYSCMLBK-UHFFFAOYSA-K 0.000 description 1
- 150000002739 metals Chemical class 0.000 description 1
- 238000010079 rubber tapping Methods 0.000 description 1
- 239000011833 salt mixture Substances 0.000 description 1
- 150000003839 salts Chemical class 0.000 description 1
- 239000011780 sodium chloride Substances 0.000 description 1
- 239000007787 solid Substances 0.000 description 1
- 239000010959 steel Substances 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
Classifications
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22B—PRODUCTION AND REFINING OF METALS; PRETREATMENT OF RAW MATERIALS
- C22B26/00—Obtaining alkali, alkaline earth metals or magnesium
- C22B26/20—Obtaining alkaline earth metals or magnesium
- C22B26/22—Obtaining magnesium
Definitions
- This invention relates to the melting and/or refining of magnesium and magnesium alloys prior to casting.
- Fluxes of low melting point such as carnallite
- magnesium chloride and sodium chloride are eminently suitable for covering and protecting the metal during and after melting, but their separation from the molten metal is very difficult and troublesome.
- Fluxes of high melting point for instance, mixtures of anhydrous magnesium chloride with substances which do not form with magnesium chloride eutectic mixtures of low melting point (compare English Patent No. 219,287) are not capable of protecting the metal from oxidation during the temperature interval between the melting point of the metal and that of the flux which is higher.
- the flux should melt at a temperature lower than the melting points of the metals or alloys under consideration, which in the present instance are of the order of from about 630 C. to
- the present invention reverts to the-use of anhydrous magnesium chloride, which I have now found can be made with magnesium fluoride into a flux which will melt at a temperature considerably below the melting point of magnesium and its usual alloys, and thus enable the melting and refining of magnesium and such alloys to be carried out at temperatures considerably below 800 C., with adequate protection of the metal during melting, provided that the two salts are present in certain proportions, and that the salt mixture is reduced to the molten state prior to its use as a flux.
- the invention consists in a flux for the melting or refining of magnesium, or both melting and refining of magnesium and magnesium alloys prior to casting, comprising anhydrous magnesium chloride and magnesium fluoride melted together in proportions from about 50 to about 80 per cent, by weight of anhydrous magnesium chloride, and about 50 to about 20 per cent, by weight of magnesium fluoride.
- the fused material may be cooled and more or less finely divided prior to use or it may be applied to the heated or unheated metal to be refined whilst still retaining part at least of the heat employed for fusing the flux.
- the invention also consists in fluxes substantantially as-herein described.
- the flux contains about .60 per cent, of anhydrous magnesium chloride and 40per cent, magnesium fluoride.
- the latter flux after the intimate contact of its constituents afforded by the initial fusion, melts at a temperature inthe neighbourhood of 610 C.
- the melting points of the-order of 630 C., to 650 C. so that the flux prepared according to the present invention will fuse and cover the metal before the latter assumes the molten state.
- the flux has excellent refining .the metal and alloys under consideration are of properties and forms, when suitably applied, a solid crust which not only effects a complete separation of the flux and impurities from the metal, but also serves to protect the molten metal after the refining stage of the process has been completed, and until the metal isv in the correct conditionfor pouring into the mould.
- the invention may be carriedinto effect by way of example in the following manner: A steel or cast iron crucible is preheated,,and the metal to be melted placed in it. At the first signs of melting a small quantity of the previously melted and crushed flux, just sufiicient to prevent oxidation, is sprinkled over it. If more metal is added in the crucible, additional flux should again be sprinkled overthis added metal.
- the temperature is allowed to rise to the region of -680 C.-'700 C., and a sufiicient quantity of the flux added to deoxidize and refine the metal.
- This flux again melts in a few minutes, and is vigorously stirred into the molten metal.
- the crucible "and its contents are then raised to and maintained at a temperature of 760 C. for a short period during which the covering flux completely hardens and separates effectively, together with the entrained impurities from the molten metal beneath.
- the temperature of the metal is then adjusted to a desirable pouring temperature, and the metal is poured into the mould by making a small aperture in the crust, or other convenient method of tapping, leaving the hard crust in its original position in the crucible.
- the invention is not limited to the use of. a
- magnesium metal is intended to embrace pure magnesium and alloys of the types referred to above.
- the improvement which comprises forming a fiux by melting together about 50 to 80 parts of anhydrous MgC12 and about 50 to' 20 parts of MgFa solidifying the melt so obtained and breaking it, all prior to use of said material as a fiux.
- Process of treating magnesium which comprises placing the metal to be melted in a container, heating the said container and addingto it prior to the melting of the metal, a flux preparedaccording to claim 1.
- Process of treating magnesium which comprises heating the container serving to melt the metal, adding to the metal as'soon as this melts, a small quantity of flux obtained according to claim 1, subsequently adding to the metal when this is completely molten alargerquantity of the said flux sufllcient to deoxidize and refine the said metal, stirring the flux into the molten metal, heating the metal to a temperature of about 760- C. leaving the metal and flux in repose for a short period, and finally separating the metal and the solidified flux so formed.
- the improvement'as described which comprises forming a fiux by melting together about 50 to 80 parts of MgClr and 50 to 20 parts of MgFz, said materials being substantially anhydrous, and applying said flux to magnesium metal under treatment while at below the melting point of anhydrous MgCl.
- the herein described method which comprises forming a flux as in claim 8, and bringing the said flux and magnesium metal into a receptacle, adding enough heat to the magnesium metal and flux, at some stage of the treatment to liquefy both said metal and flux, and agitating the liquefied flux and liquefied metal together, while in a liquid state to refine-said metal, and thereafter allowing separation of said metal and fiux from each other while in a liquefied condition, whereby it becomes unnecessary to heat said metal to the melting point of anhydrous magnesium chloride.
- Product for the treatment of magnesium which comprises a substantially anhydrous, intimate and homogeneous mixture consisting essentially of about 50 to 80 parts of magnesium.
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- Engineering & Computer Science (AREA)
- Chemical & Material Sciences (AREA)
- Life Sciences & Earth Sciences (AREA)
- Environmental & Geological Engineering (AREA)
- General Life Sciences & Earth Sciences (AREA)
- Geology (AREA)
- Manufacturing & Machinery (AREA)
- Materials Engineering (AREA)
- Mechanical Engineering (AREA)
- Metallurgy (AREA)
- Organic Chemistry (AREA)
- Treatment Of Steel In Its Molten State (AREA)
Description
Patented June 11, 1935 MELTING AND/OR REFINING OF MAGNE- I SIUM AND MAGNESIUM ALLOYS PRIOR TO CAS TING, AND FLUX THEREFOR Leslie George Day, Taplow, England, assignor to Magnesium Castings and Products Limited,
Slough, England No Drawing. Application September 22, 1934,
Serial No. 745,044. In Great Britain Septemher 21, 1933 12 Claims.
This invention relates to the melting and/or refining of magnesium and magnesium alloys prior to casting.
It is well known that the refining and preparation for casting of magnesium and its alloys present various difficulties which are mainly associated with the necessary fluxes and refining agents.
Fluxes of low melting point such as carnallite,
or mixtures of magnesium chloride and sodium chloride are eminently suitable for covering and protecting the metal during and after melting, but their separation from the molten metal is very difficult and troublesome.
Fluxes of high melting point, for instance, mixtures of anhydrous magnesium chloride with substances which do not form with magnesium chloride eutectic mixtures of low melting point (compare English Patent No. 219,287) are not capable of protecting the metal from oxidation during the temperature interval between the melting point of the metal and that of the flux which is higher.
Further with such high melting point fluxes a refining temperature exceeding, and in some cases considerably exceeding 800 C. is used (compare English Patent No. 182,948)
Since the best pouring temperature for magnesium and alloys composed mainly of magnesium is in the neighbourhood of 740 C., the use of refining temperatures of 800 C. and upwards does not represent the best economy.
The properties of a flux suitable for the most economical. preparation of the metal may be summarized as follows:
(1) The flux should melt at a temperature lower than the melting points of the metals or alloys under consideration, which in the present instance are of the order of from about 630 C. to
about 650 C., in order to prevent the energetic oxidation which would otherwise occur at the surface of the molten metal.
oleaned, and until it is ready vide a flux, or an improved or modified flux, having the above features.
It is stated in the English Patent No. 375,743 and in British Patent 401,672 and in U. S. Patent 1,935,284 that in practice no iiux composed exclusively of anhydrous magnesium chloride with sufioient quantities of magnesium fluoride to act as an eflicient' refining agent will melt at a sumciently low temperature to allow of refining being carried out below 800 C. The flux with which that specification dealt departed from the stated prior knowledge in the direction of employing hydrous magnesium chloride.
The present invention reverts to the-use of anhydrous magnesium chloride, which I have now found can be made with magnesium fluoride into a flux which will melt at a temperature considerably below the melting point of magnesium and its usual alloys, and thus enable the melting and refining of magnesium and such alloys to be carried out at temperatures considerably below 800 C., with adequate protection of the metal during melting, provided that the two salts are present in certain proportions, and that the salt mixture is reduced to the molten state prior to its use as a flux.
The invention consists in a flux for the melting or refining of magnesium, or both melting and refining of magnesium and magnesium alloys prior to casting, comprising anhydrous magnesium chloride and magnesium fluoride melted together in proportions from about 50 to about 80 per cent, by weight of anhydrous magnesium chloride, and about 50 to about 20 per cent, by weight of magnesium fluoride. The fused material may be cooled and more or less finely divided prior to use or it may be applied to the heated or unheated metal to be refined whilst still retaining part at least of the heat employed for fusing the flux.
The invention also consists in fluxes substantantially as-herein described.
In carrying the invention into eifect in one form, by way of example,the flux contains about .60 per cent, of anhydrous magnesium chloride and 40per cent, magnesium fluoride. The latter flux, after the intimate contact of its constituents afforded by the initial fusion, melts at a temperature inthe neighbourhood of 610 C.
As previously mentioned, the melting points of the-order of 630 C., to 650 C., so that the flux prepared according to the present invention will fuse and cover the metal before the latter assumes the molten state. The flux has excellent refining .the metal and alloys under consideration are of properties and forms, when suitably applied, a solid crust which not only effects a complete separation of the flux and impurities from the metal, but also serves to protect the molten metal after the refining stage of the process has been completed, and until the metal isv in the correct conditionfor pouring into the mould.
The invention may be carriedinto effect by way of example in the following manner: A steel or cast iron crucible is preheated,,and the metal to be melted placed in it. At the first signs of melting a small quantity of the previously melted and crushed flux, just sufiicient to prevent oxidation, is sprinkled over it. If more metal is added in the crucible, additional flux should again be sprinkled overthis added metal.
When the metal is completely molt'en, the temperature is allowed to rise to the region of -680 C.-'700 C., and a sufiicient quantity of the flux added to deoxidize and refine the metal. This flux again melts in a few minutes, and is vigorously stirred into the molten metal. r After sufilcient stirring, the fiux rises to the surface of the metal, completely covering the melt, and having an appreciable thickness. The crucible "and its contents are then raised to and maintained at a temperature of 760 C. for a short period during which the covering flux completely hardens and separates effectively, together with the entrained impurities from the molten metal beneath. The temperature of the metal is then adjusted to a desirable pouring temperature, and the metal is poured into the mould by making a small aperture in the crust, or other convenient method of tapping, leaving the hard crust in its original position in the crucible.
, The invention is not limited to the use of. a
'of 60 per cent of, anhydrous magnesiumchloride and 40 per cent magnesium fluoride, but
extends to the range from about 50 to about per cent of anhydrous magnesium chloride, and about 50 to about'20 per cent of magnesium fluoride.
In the appended claims, the term magnesium metal is intended to embrace pure magnesium and alloys of the types referred to above.
I claim: r
1. In the process of treating magnesium metal,
' the improvement which comprises forming a fiux by melting together about 50 to 80 parts of anhydrous MgC12 and about 50 to' 20 parts of MgFa solidifying the melt so obtained and breaking it, all prior to use of said material as a fiux.
2. Process of treating magnesium which comprises placing the metal to be melted in a container, heating the said container and addingto it prior to the melting of the metal, a flux preparedaccording to claim 1.
3. Process of treating magnesium which comprises heating the container serving to melt the metal, adding to the metal as'soon as this melts, a small quantity of flux obtained according to claim 1, subsequently adding to the metal when this is completely molten alargerquantity of the said flux sufllcient to deoxidize and refine the said metal, stirring the flux into the molten metal, heating the metal to a temperature of about 760- C. leaving the metal and flux in repose for a short period, and finally separating the metal and the solidified flux so formed. s a
4. In the process of treating magnesium met the improvement which comprises forming a flux by melting together about 50 to 80 parts of anhydrous MgClz and about 50 to 20 parts of MgFz, and thereafter applying said flux in the anhydrous MgClz and about 50 to 20 parts of MgFz, and applying said mixture as a flux in the treatment of magnesium metal.
7. In the treatment of magnesium metal, the herein described process which comprises forming a fiux as set forth in claim 4, placing the magnesium metal in a container and heating said metal, adding a small quantity of the above mentioned fiux before any considerable amount of melting of the said metal has occurred, adding a much larger quantity of the flux when the metal has melted, applying heat to melt said added flux, agitating the metal and flux together sufliciently to refine the metal and allowing separation of said metal and flux from each other by gravity,
8. In the process of treating magnesium metal, the improvement'as described, which comprises forming a fiux by melting together about 50 to 80 parts of MgClr and 50 to 20 parts of MgFz, said materials being substantially anhydrous, and applying said flux to magnesium metal under treatment while at below the melting point of anhydrous MgCl.
9. In the treatment of molten magnesium metal, the herein described method which comprises forming a flux as in claim 8, and bringing the said flux and magnesium metal into a receptacle, adding enough heat to the magnesium metal and flux, at some stage of the treatment to liquefy both said metal and flux, and agitating the liquefied flux and liquefied metal together, while in a liquid state to refine-said metal, and thereafter allowing separation of said metal and fiux from each other while in a liquefied condition, whereby it becomes unnecessary to heat said metal to the melting point of anhydrous magnesium chloride.
10. In the process of treating magnesium metal, the improvement as described, which comprises forming a flux by melting together about 50 to 80 parts of MgClz and 50 to '20 parts of MgFz, said, materials being substantially anhydrous. I
11. Product for the treatment of magnesium which comprises a substantially anhydrous, intimate and homogeneous mixture consisting essentially of about 50 to 80 parts of magnesium.
chloride and about 50 to 20 parts of magnesium fluoride, and which mixture will melt at a temperature below 630 C., said mixture being in a comminuted. condition.
12. A fluxing material suitable for use in melt-'
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB2004689X | 1933-09-21 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| US2004689A true US2004689A (en) | 1935-06-11 |
Family
ID=10895813
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| US745044A Expired - Lifetime US2004689A (en) | 1933-09-21 | 1934-09-22 | Melting and/or refining of magnesium and magnesium alloys prior to casting, and fluxtherefor |
Country Status (1)
| Country | Link |
|---|---|
| US (1) | US2004689A (en) |
-
1934
- 1934-09-22 US US745044A patent/US2004689A/en not_active Expired - Lifetime
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