US2956873A - Method of removing hydrogen from molten metal - Google Patents

Method of removing hydrogen from molten metal Download PDF

Info

Publication number
US2956873A
US2956873A US702751A US70275157A US2956873A US 2956873 A US2956873 A US 2956873A US 702751 A US702751 A US 702751A US 70275157 A US70275157 A US 70275157A US 2956873 A US2956873 A US 2956873A
Authority
US
United States
Prior art keywords
metal
molten
carbonate
hydrogen
parts
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
Application number
US702751A
Inventor
Emmott Joseph Gordon
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Foundry Services International Ltd
Original Assignee
Foundry Services International Ltd
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Foundry Services International Ltd filed Critical Foundry Services International Ltd
Application granted granted Critical
Publication of US2956873A publication Critical patent/US2956873A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

Links

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
    • C22B9/00—General processes of refining or remelting of metals; Apparatus for electroslag or arc remelting of metals
    • C22B9/05—Refining by treating with gases, e.g. gas flushing also refining by means of a material generating gas in situ
    • 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
    • C22B15/00—Obtaining copper
    • C22B15/0026—Pyrometallurgy
    • C22B15/006—Pyrometallurgy working up of molten copper, e.g. refining
    • 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
    • C22B23/00—Obtaining nickel or cobalt
    • C22B23/06—Refining
    • 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
    • C22B9/00—General processes of refining or remelting of metals; Apparatus for electroslag or arc remelting of metals
    • C22B9/10—General processes of refining or remelting of metals; Apparatus for electroslag or arc remelting of metals with refining or fluxing agents; Use of materials therefor, e.g. slagging or scorifying agents

Definitions

  • This invention relates to the production of non-ferrous metals, e.g. copper, nickel and alloys of copper and of nickel.
  • the molten metal may contain occluded gases which tend to give rise to the presence of minute bubbles or porosities in the solidified metal. It is known in the case of copper alloys to bubble nitrogen through the metal in order to de-gas it. However, the method is diflicult to carry out in practice and no simple method of degassing such metals is indeed known.
  • molten copper and nickel and their alloys and other molten nonferrous metals may be efficiently and simply degassed by generating within the body of the molten metal certain types of gas which will act to flush the metal and entrain occluded gases.
  • a method of removing a dissolved gas from molten non-ferrous metal comprises introducing into the molten non-ferrous metal, preferably towards the base thereof, a solid compound which at the temperature of the molten non-ferrous metal will generate carbon monoxide and/or carbon dioxide, the generated gas being either free from the gas which is to be removed or having a partial pressure of that gas which is less than the equivalent internal pressure of the said dissolved gas in the said molten metal.
  • the gas to be removed will be hydrogen and the expression equivalent internal pressure is used to define the hydrogen pressure in the metal equivalent to that partial pressure of hydrogen above the metal which would be in equilibrium with the dissolved hydrogen.
  • the generation of carbon monoxide and carbon diox ide may be achieved by introducing into the molten nonferrous metal such materials as dolomite (magnesium carbonate-calcium carbonate) limestone, preferably coated with fluorspar, marble and other alkaline earth metal carbonates, e.g. barium carbonate.
  • dolomite magnesium carbonate-calcium carbonate
  • fluorspar calcium carbonate-calcium carbonate
  • marble and other alkaline earth metal carbonates e.g. barium carbonate.
  • the foregoing materials may with advantage be used in association with a proportion of carbon such as to ensure as far as possible that any carbon dioxide generated is converted to carbon monoxide, thus increasing the net volume of gas.
  • a proportion of a refractory material such as magnesia, e.g.
  • a material of particular value comprises marble chips and powder bonded together with a silicate, e.g. a mixture varying from 75 parts chips and 25 parts powder to 50 parts chips and 50 parts powder, bonded together in the proportion 90 parts of the mixture with 10 parts of sodium silicate to 80 parts of the mixture with 20 parts of sodium silicate.
  • a preferred composition consists of 83-85 parts of the mixture with -17 parts of sodium silicate, the mixture being 70% chips and 30% powder.
  • the composition is preferably in a form presenting a large surface area, e.g. as a fluted cylindrical block.
  • the additive material employed should generally have a moisture content below 1.5% by weight and preferably below 0.15%.
  • Such low moisture content can be achieved by heating the additive to a temperature as high as possible but not reaching the temperature at which the additive commences to generate carbon dioxide or carbon monoxide.
  • the heat treatment may be at temperatures of 400 C. or more but not exceeding about 600 C. at which temperature marble begins to decompose.
  • silicate bonded marble obtained by mixing together parts by weight of marble chips and 30 parts of marble powder and bonding parts of that mixture with 15 parts of sodium silicate and stoving the product at 400 C. for 6 hours, whereby the moisture content of the product is reduced to 0.12% by weight.
  • the additive must have as low a moisture content as possible since the less hydrogen there is in the generated bubbles of carbon dioxide and/or carbon monoxide, the greater will be the efiect of these bubbles in entraining hydrogen from the non-ferrous metal.
  • the foregoing example uses marble as the gas-generating agent any other solid substance which at the temperature of the molten non-ferrous metal will generate carbon dioxide and/or carbon monoxide may be used.
  • Marble is a material of choice because of its cheapness but any carbonate particularly of an alkaline earth metal, and particularly any natural carbonate may be used subject only to the overall consideration that if a natural carbonate is used it should not simultaneously introduce into the non-ferrous metal melt any unwanted constituents.
  • a method for removing hydrogen from molten nonferrous metal which comprises introducing into the molten non-ferrous metal a solid alkaline earth metal carbonate having a moisture content below about 0.15% obtained by heating said carbonate to between about 400 C. and about 600 C. to achieve incipient decomposition thereof.
  • a method for removing hydrogen from molten nonferrous metal which comprises introducing into the molten non-ferrous metal marble having a moisture content below about 0.15% obtained by heating said marble to a temperature between about 400 C. and about 600 C. to achieve incipient decomposition thereof.
  • a method for removing hydrogen from molten nonferrous metal which comprises introducing into the molten non-ferrous metal a material consisting of marble fragments bonded together with a silicate, said material having a moisture content below about 0.15% obtained by heating said material to a temperature of between about 400 C. and about 600 C. to achieve incipient decomposition of said marble.
  • a method for removing hydrogen from molten nonferrous metal which comprises introducing into the molten non-ferrous metal a material comprising an alkaline earth metal carbonate and carbon, said material having a moisture content below about 0.15% obtained by heating said material to a temperature of between about 400 C. and about 600 C. to achieve incipient decomposition of said carbonate.
  • a method for removing hydrogen from molten nonferrous metal which comprises introducing into the molten non-ferrous metal a material comprising dolomite and carbon, said material having a moisture content below about 0.15% obtained by heating said material to a temperature of between about 400 C. and about 600 C. to achieve incipient decomposition of said carbonate.
  • a method for removing hydrogen from molten metal consisting essentially of copper which comprises introducing into the molten metal consisting essentially of copper a solid alkaline earth metal carbonate having a moisture content below about 1.5% obtained by heating said carbonate to a temperature of between about 400 C. and about 600 C. to achieve incipient decomposition of said carbonate.

Description

United States Patent IVIETHOD 0F REMOVING HYDROGEN FROM MOLTEN METAL Joseph Gordon Emmott, Birmingham, England, assignor,
hy mesne assignments, to Foundry Services International Limited, Birmingham, England, a British company No Drawing. Filed Dec. 16, 1957, Ser. No. 702,751
Claims priority, application Great Britain Feb. 4, 1957 6 Claims. (Cl. 75-93) This invention relates to the production of non-ferrous metals, e.g. copper, nickel and alloys of copper and of nickel.
In the production of these metals it is a well known difficulty that the molten metal may contain occluded gases which tend to give rise to the presence of minute bubbles or porosities in the solidified metal. It is known in the case of copper alloys to bubble nitrogen through the metal in order to de-gas it. However, the method is diflicult to carry out in practice and no simple method of degassing such metals is indeed known.
It has now been discovered, however, that molten copper and nickel and their alloys and other molten nonferrous metals may be efficiently and simply degassed by generating within the body of the molten metal certain types of gas which will act to flush the metal and entrain occluded gases.
According to the present invention a method of removing a dissolved gas from molten non-ferrous metal comprises introducing into the molten non-ferrous metal, preferably towards the base thereof, a solid compound which at the temperature of the molten non-ferrous metal will generate carbon monoxide and/or carbon dioxide, the generated gas being either free from the gas which is to be removed or having a partial pressure of that gas which is less than the equivalent internal pressure of the said dissolved gas in the said molten metal. Generally the gas to be removed will be hydrogen and the expression equivalent internal pressure is used to define the hydrogen pressure in the metal equivalent to that partial pressure of hydrogen above the metal which would be in equilibrium with the dissolved hydrogen.
The generation of carbon monoxide and carbon diox ide may be achieved by introducing into the molten nonferrous metal such materials as dolomite (magnesium carbonate-calcium carbonate) limestone, preferably coated with fluorspar, marble and other alkaline earth metal carbonates, e.g. barium carbonate. The foregoing materials may with advantage be used in association with a proportion of carbon such as to ensure as far as possible that any carbon dioxide generated is converted to carbon monoxide, thus increasing the net volume of gas. Moreover, since the foregoing carbonate materials react very rapidly it is usually desirable to associate them with a proportion of a refractory material, such as magnesia, e.g. by reducing the materials to powder or granular mixture and compacting or binding them to a readily handleable shape. A material of particular value comprises marble chips and powder bonded together with a silicate, e.g. a mixture varying from 75 parts chips and 25 parts powder to 50 parts chips and 50 parts powder, bonded together in the proportion 90 parts of the mixture with 10 parts of sodium silicate to 80 parts of the mixture with 20 parts of sodium silicate. A preferred composition consists of 83-85 parts of the mixture with -17 parts of sodium silicate, the mixture being 70% chips and 30% powder. The composition is preferably in a form presenting a large surface area, e.g. as a fluted cylindrical block.
It is important to avoid introducing with the additive into the molten metal any important quantity of moisture and accordingly the additive material employed should generally have a moisture content below 1.5% by weight and preferably below 0.15%. Such low moisture content can be achieved by heating the additive to a temperature as high as possible but not reaching the temperature at which the additive commences to generate carbon dioxide or carbon monoxide. In the case of marble the heat treatment may be at temperatures of 400 C. or more but not exceeding about 600 C. at which temperature marble begins to decompose.
The presence of moisture in the additive causes a hydrogen concentration in the gas bubbles generated. Hence in order for the gas bubbles to be effective in entraining hydrogen from the non-ferrous metal it is necessary, as stated above, that the partial pressure of hydrogen in the generated bubbles should be less than the equivalent internal pressure of hydrogen in the metal.
The quantity of solid material addedto the molten metal in accordance with the invention, and the time dur- The following mixture is tableted using sodium silicate as binding agent:
Parts by weight Dolomite 88 Carbon 12 Tablets weighing /2 to 1 lb. of the said mixture are employed per ton of molten copper or copper-based alloy, the tablets being plunged when the metal is at 1000- 1200" C. 4
An excellent degassing is thus obtained.
A similar result is obtained by using, instead of the said tableted mixture, silicate bonded marble obtained by mixing together parts by weight of marble chips and 30 parts of marble powder and bonding parts of that mixture with 15 parts of sodium silicate and stoving the product at 400 C. for 6 hours, whereby the moisture content of the product is reduced to 0.12% by weight.
It will be appreciated from the foregoing that to secure an optimum degassing of non-ferrous metal the additive must have as low a moisture content as possible since the less hydrogen there is in the generated bubbles of carbon dioxide and/or carbon monoxide, the greater will be the efiect of these bubbles in entraining hydrogen from the non-ferrous metal. Whilst the foregoing example uses marble as the gas-generating agent any other solid substance which at the temperature of the molten non-ferrous metal will generate carbon dioxide and/or carbon monoxide may be used. Marble is a material of choice because of its cheapness but any carbonate particularly of an alkaline earth metal, and particularly any natural carbonate may be used subject only to the overall consideration that if a natural carbonate is used it should not simultaneously introduce into the non-ferrous metal melt any unwanted constituents.
Whilst the invention has been particularly described with reference to the treatment of copper and its alloys it is to be understood that these are only by way of example and that the invention is applicable to the removal of hydrogen from any non-ferrous metal, e.g. nickel, cobalt, chromium, molybdenum, vanadium, tin, gold and silver and alloys of any of these with each otheror with other non-ferrous metals or semi-metals.
I claim as my invention:
1. A method for removing hydrogen from molten nonferrous metal which comprises introducing into the molten non-ferrous metal a solid alkaline earth metal carbonate having a moisture content below about 0.15% obtained by heating said carbonate to between about 400 C. and about 600 C. to achieve incipient decomposition thereof.
2. A method for removing hydrogen from molten nonferrous metal which comprises introducing into the molten non-ferrous metal marble having a moisture content below about 0.15% obtained by heating said marble to a temperature between about 400 C. and about 600 C. to achieve incipient decomposition thereof.
3. A method for removing hydrogen from molten nonferrous metal which comprises introducing into the molten non-ferrous metal a material consisting of marble fragments bonded together with a silicate, said material having a moisture content below about 0.15% obtained by heating said material to a temperature of between about 400 C. and about 600 C. to achieve incipient decomposition of said marble.
4. A method for removing hydrogen from molten nonferrous metal which comprises introducing into the molten non-ferrous metal a material comprising an alkaline earth metal carbonate and carbon, said material having a moisture content below about 0.15% obtained by heating said material to a temperature of between about 400 C. and about 600 C. to achieve incipient decomposition of said carbonate.
5. A method for removing hydrogen from molten nonferrous metal which comprises introducing into the molten non-ferrous metal a material comprising dolomite and carbon, said material having a moisture content below about 0.15% obtained by heating said material to a temperature of between about 400 C. and about 600 C. to achieve incipient decomposition of said carbonate.
6. A method for removing hydrogen from molten metal consisting essentially of copper which comprises introducing into the molten metal consisting essentially of copper a solid alkaline earth metal carbonate having a moisture content below about 1.5% obtained by heating said carbonate to a temperature of between about 400 C. and about 600 C. to achieve incipient decomposition of said carbonate.
References Cited in the file of this patent

Claims (1)

1. A METHOD FOR REMOVING HYDROGEN FROM MOLTEN NONFERROUS METAL WHICH COMPRISES INTRODUCING INTO THE MOLTEN NON-FERROUS METAL A SOLID ALKALINE EARTH METAL CARBONATE HAVING A MOISTURE CONTENT BELOW ABOUT 0.15% OBTAINED BY HEATING SAID CARBONATE TO BETWEEN ABOUT 400*C. AND ABOUT 600*C. TO ACHIEVE INCIPIENT DECOMPOSITION THEREOF.
US702751A 1957-02-04 1957-12-16 Method of removing hydrogen from molten metal Expired - Lifetime US2956873A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB2956873X 1957-02-04

Publications (1)

Publication Number Publication Date
US2956873A true US2956873A (en) 1960-10-18

Family

ID=10918573

Family Applications (1)

Application Number Title Priority Date Filing Date
US702751A Expired - Lifetime US2956873A (en) 1957-02-04 1957-12-16 Method of removing hydrogen from molten metal

Country Status (1)

Country Link
US (1) US2956873A (en)

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3144323A (en) * 1959-05-01 1964-08-11 Foseco Int Treatment of molten light alloys
US20040113130A1 (en) * 1999-10-13 2004-06-17 Nagel Christopher J. Composition of matter tailoring: system I
US20060174570A1 (en) * 2005-01-06 2006-08-10 Logan Richard J Glue manifold for a functional shutter
US20060186800A1 (en) * 2005-02-23 2006-08-24 Electromagnetics Corporation Compositions of matter: system II
US9790574B2 (en) 2010-11-22 2017-10-17 Electromagnetics Corporation Devices for tailoring materials

Citations (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US287117A (en) * 1883-10-23 Process of preparing powdered or granulated ores for furnaces
US977406A (en) * 1910-03-01 1910-11-29 Martha P Jewett Composition of matter to be used for the purpose of fluxing metals.
US1841599A (en) * 1930-01-09 1932-01-19 Refined Steel Products Company Method of treating nonferrous metals
US1932252A (en) * 1931-08-15 1933-10-24 Alloy Res Corp Process of producing alloys
US1978537A (en) * 1931-05-16 1934-10-30 William R Jeavons Process of refining metals
US1994679A (en) * 1931-08-15 1935-03-19 Alloy Res Corp Process of producing alloys
US2073020A (en) * 1933-01-10 1937-03-09 Cie Generale D Electro Metallu Method of improving the physical and mechanical properties of alloys
US2073019A (en) * 1932-11-28 1937-03-09 Cie Generale D Electro Metallu Process for the purification of metals and metallic alloys
US2079901A (en) * 1934-07-05 1937-05-11 Burtner Fleeger Metallurgical addition agent and process

Patent Citations (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US287117A (en) * 1883-10-23 Process of preparing powdered or granulated ores for furnaces
US977406A (en) * 1910-03-01 1910-11-29 Martha P Jewett Composition of matter to be used for the purpose of fluxing metals.
US1841599A (en) * 1930-01-09 1932-01-19 Refined Steel Products Company Method of treating nonferrous metals
US1978537A (en) * 1931-05-16 1934-10-30 William R Jeavons Process of refining metals
US1932252A (en) * 1931-08-15 1933-10-24 Alloy Res Corp Process of producing alloys
US1994679A (en) * 1931-08-15 1935-03-19 Alloy Res Corp Process of producing alloys
US2073019A (en) * 1932-11-28 1937-03-09 Cie Generale D Electro Metallu Process for the purification of metals and metallic alloys
US2073020A (en) * 1933-01-10 1937-03-09 Cie Generale D Electro Metallu Method of improving the physical and mechanical properties of alloys
US2079901A (en) * 1934-07-05 1937-05-11 Burtner Fleeger Metallurgical addition agent and process

Cited By (19)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3144323A (en) * 1959-05-01 1964-08-11 Foseco Int Treatment of molten light alloys
US6921497B2 (en) * 1999-10-13 2005-07-26 Electromagnetics Corporation Composition of matter tailoring: system I
US20040129925A1 (en) * 1999-10-13 2004-07-08 Nagel Christopher J. Composition of matter tailoring: system I
US20060145128A1 (en) * 1999-10-13 2006-07-06 Nagel Christopher J Composition of matter tailoring: system I
US20060102881A1 (en) * 1999-10-13 2006-05-18 Nagel Christopher J Composition of matter tailoring: system I
US20040231458A1 (en) * 1999-10-13 2004-11-25 Nagel Christopher J. Composition of matter tailoring: system I
US20040250650A1 (en) * 1999-10-13 2004-12-16 Nagel Christopher J. Composition of matter tailoring: system I
US20050064190A1 (en) * 1999-10-13 2005-03-24 Nagel Christopher J. Composition of matter tailoring: system I
US20040113130A1 (en) * 1999-10-13 2004-06-17 Nagel Christopher J. Composition of matter tailoring: system I
US7704403B2 (en) 1999-10-13 2010-04-27 Electromagnetic Corporation Composition of matter tailoring: system I
US20040119053A1 (en) * 1999-10-13 2004-06-24 Nagel Christopher J. Composition of matter tailoring: System I
US20040129350A1 (en) * 1999-10-13 2004-07-08 Nagel Christopher J. Composition of matter tailoring: system I
US7491348B2 (en) 1999-10-13 2009-02-17 Electromagnetics Corporation Composition of matter tailoring: system I
US7238297B2 (en) 1999-10-13 2007-07-03 Electromagnetics Corporation Composition of matter tailoring: system I
US7252793B2 (en) 1999-10-13 2007-08-07 Electromagnetics Corporation Composition of matter tailoring: system I
US20060174570A1 (en) * 2005-01-06 2006-08-10 Logan Richard J Glue manifold for a functional shutter
US20060186800A1 (en) * 2005-02-23 2006-08-24 Electromagnetics Corporation Compositions of matter: system II
US7655160B2 (en) 2005-02-23 2010-02-02 Electromagnetics Corporation Compositions of matter: system II
US9790574B2 (en) 2010-11-22 2017-10-17 Electromagnetics Corporation Devices for tailoring materials

Similar Documents

Publication Publication Date Title
US3592637A (en) Method for adding metal to molten metal baths
US4648901A (en) Introducing one or more metals into a melt comprising aluminum
KR910700359A (en) Method for manufacturing metals, alloys and ceramic materials
GB1366548A (en) Process for recovering metal from slags
US3637373A (en) Compositions for the treatment of molten iron
US2881068A (en) Method of treating a ferrous melt with a porous sintered metal body impregnated with a treating agent
US2956873A (en) Method of removing hydrogen from molten metal
US1922037A (en) Treatment of metals
US1975084A (en) Composition of matter and process of treating molten metals
US3503738A (en) Metallurgical process for the preparation of aluminum-boron alloys
US3385696A (en) Process for producing nickel-magnesium product by powder metallurgy
US3144323A (en) Treatment of molten light alloys
US2481599A (en) Alloy addition agent
US2823112A (en) Flux compound
US4179287A (en) Method for adding manganese to a molten magnesium bath
US2287771A (en) Production of powdered alloys
US3314787A (en) Method for producing an mg addition agent
US2361925A (en) Preparation of manganese products
US3801311A (en) Method of introducing rare earth metals into addition alloys
US2610911A (en) Metallurgy
US3189444A (en) Metallic composition and method of making
US2538263A (en) Method of producing ductile cast iron
US2926080A (en) Process for the introduction of rare earths in addition alloys
US2965477A (en) Treatment of molten metals
US3854935A (en) Grain refining compositions and method of refining aluminum therewith