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
  • C22B21/00—Obtaining aluminium
  • C22B21/0038—Obtaining aluminium by other processes
  • C22B21/0053—Obtaining aluminium by other processes from other aluminium compounds
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B22—CASTING; POWDER METALLURGY
  • B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
  • B22F9/00—Making metallic powder or suspensions thereof
  • B22F9/16—Making metallic powder or suspensions thereof using chemical processes
  • B22F9/18—Making metallic powder or suspensions thereof using chemical processes with reduction of metal compounds
  • B22F9/20—Making metallic powder or suspensions thereof using chemical processes with reduction of metal compounds starting from solid metal compounds
  • B22F9/22—Making metallic powder or suspensions thereof using chemical processes with reduction of metal compounds starting from solid metal compounds using gaseous reductors
• • 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
  • C22B21/00—Obtaining aluminium
  • C22B21/02—Obtaining aluminium with reducing
• • 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
  • C22B3/00—Extraction of metal compounds from ores or concentrates by wet processes
  • C22B3/04—Extraction of metal compounds from ores or concentrates by wet processes by leaching
  • C22B3/06—Extraction of metal compounds from ores or concentrates by wet processes by leaching in inorganic acid solutions, e.g. with acids generated in situ; in inorganic salt solutions other than ammonium salt solutions
• • 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
  • C22B3/00—Extraction of metal compounds from ores or concentrates by wet processes
  • C22B3/20—Treatment or purification of solutions, e.g. obtained by leaching
  • C22B3/44—Treatment or purification of solutions, e.g. obtained by leaching by chemical processes
  • C22B3/46—Treatment or purification of solutions, e.g. obtained by leaching by chemical processes by substitution, e.g. by cementation
• • 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
  • C22B5/00—General methods of reducing to metals
• • C—CHEMISTRY; METALLURGY
  • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
  • C22C—ALLOYS
  • C22C1/00—Making non-ferrous alloys
  • C22C1/04—Making non-ferrous alloys by powder metallurgy
• • C—CHEMISTRY; METALLURGY
  • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
  • C22C—ALLOYS
  • C22C1/00—Making non-ferrous alloys
  • C22C1/04—Making non-ferrous alloys by powder metallurgy
  • C22C1/0433—Nickel- or cobalt-based alloys
  • C22C1/0441—Alloys based on intermetallic compounds of the type rare earth - Co, Ni
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
  • Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
  • Y02P10/00—Technologies related to metal processing
  • Y02P10/20—Recycling

Definitions

• the cyanide complex is treated in crystalline form with dry hydrogen at temperatures generally between 700 and 1300C. any hydride formed being decomposed by heating.
• the present invention relates to a method of producing elemental metals or metal alloys and metal compositions of high purity. More particularly, the invention relates to a chemical procedure for obtaining refractory metals, from compounds containing same, with controlled composition at a relatively low cost.
• metals may be obtained from their ores by processes starting with compounds such as oxides or halides of the desired metal, which are reduced chemically or electrolytically.
• Very electropositive metals whose compounds are therefore difficult to reduce are often treated chemically by low-cost products such as hydrogen, carbon, or carbon monoxide at a very high temperature which causes the formation of stable carbides which make it impossible to prepare sufficiently pure metals. It is therefore necessary to use chemical reducing agents which are much more expensive such as alkali metals or alkaline earths, magnesium or silicon, or to employ electrolytic reduction which uses large quantities of electricity.
• the alloys of these metals are usually obtained by simultaneous fusion of the elements of the alloy when their melting points are substantially equal. When this is not the case, the less easily melted metals are dissolved in the other previously molten metals. This latter operation is usually unduly long with certain refractory metals and requires an atmosphere which is perfectly inert at the elevated temperatures required to obtain sufficiently rapid dissolution. It is also very difficult to react at high temperature a relatively volatile metal with a refractory metal and problems with contamination from the containing vessel arise.
• Another object of the invention is a chemical method of producing alloys which can be used for two or more of the above-named metals as well as binary or higher order alloys of these metals with any other metal.
• the process according to the present invention is based in principle on the reduction by hydrogen of the metal cyanide complex of the metal or the metals in question. If the cyanide complex is monometallic (i.e. containing only a single metallic element) its reduction by hydrogen yields one metal. If on the contrary the cyanide complex is polymetallic (i.e. containing several different metallic elements) its reduction yields an alloy.
• reaction (II) cyanide complex-l-hydrogen metaH-hydrocyanic acid
• the hydrocyanic acid thus obtained, with minor losses, in reaction (II) is used again for reaction (I), making a cycle which indirectly reduces the metal hydrate (hydroxide) by hydrogen, which often is impossible to do directly.
• polymetallic cyanide complexes are reduced by hydrogen according to the general reaction formula:
• the surprising discovery is that the reduction by hydrogen of a polymetallic cyanide complex according to reaction (III) yields an alloy in the form of a fine powder each granule of which is an alloy particle and not just a juxtaposition of granules of each of the component metals.
• the process according to the present invention yields an alloy formed by a homogeneous phase (solid metallic solution or definite combination) or a mixture of phases conforming to that predicted by the formula.
• the uniform alloy obtained according to the present invention has the same structure as that which is obtained by fusion and cooling of v3 the metals, with the condition, of course, that the proper thermal treatments have been carried out so that the phases appear under identical allotropic forms.
• the powders so produced can be used in powder metallurgy.
• the production of sintered-metal bearings and like parts is facilitated by the high-purity powders according to the present invention.
• the cyanide reduction process according to the present invention yields a powder whose granule size is dependent on the final temperature and also on how long this temperature is maintained. This means that metallic materials can be produced which are particularly adapted to sintering.
• the metal complex may be formed by two main process sequences, whether the complex is of the monometallic type or of the polymetallic type.
• the complex may be produced by treating a basic compound of a metal M or of several metals (M, M, M". as a simple compound. a mixed-metal compound, a coprecipitate of metals compounds, a mixture of precipitates of the metal compounds or a compound containing two or more of the metals, and preferably in the form of the oxide, hydroxide, carbonate or salts which can be considered weakly basic, with a complex acid having the general formula H, [M (CN) where M represents the same metal as that of the basic compound in the case of a monometallic complex or a different metal in the case of a polymetallic complex.
• x represents the coordination number of the Metal M
• y and p are determined by the ionic valances of the portion of the molecule in square brackets.
• the complex acid may be formed, on the one hand by ion-exchange principles and, on the other hand, by ionic displacement methods.
• an acid ion-exchange resin may be prepared and a solution of an alkali-metal (e.g. potassium) salt of the complex anion may be passed therethrough so that hydrogen ion exchanges for potassium ion and the acid appears in the eluate.
• an alkali-metal (e.g. potassium) salt of the complex anion may be passed therethrough so that hydrogen ion exchanges for potassium ion and the acid appears in the eluate.
• anion-exhange resins may be used whereby the resin is charged with the complex anion and is eluted with an acid whose anion exchanges for the complex anion so that again the complex acid appears in the eluate.
• a displacement method is used whereby, for example, a barium salt of the complex anion is reacted in aqueous solution with sulfuric acid to precipitate barium sulfate and leave complex acid in solution.
• the barium salt of the complex may be produced, in turn, by reacting the metal sulfate with barium cyanide to precipitate barium sulfate and leave the barium cyanide complex in solution.
• the hydrocyanic acid is used in a concentration of 10 to 60% by weight and in excess over the basic compound by lO to 20%.
• the use of the previously prepared complex acid requires a predetermined quantity according to the stoichiometry. It is important to observethat the solution containing the metal-metal cyanide complex should have the metals in their desired proportions in the alloy to be produced and, therefore, in the desired proportions in the cyrstalline product.
• the crystals are formed preferably by low temperature removal of the water from the solution and we may use vacuum evaporation at temperatures up to, say, 60C or removing the water by azeotropic distillation under reducedtemperatures up to 40C.
• a suitable azeotropic .entrainer for this purpose is gasoline.
• the crystals of the metal cyanide complex are first dried in a pure and dry hydrogen atmosphere or under a vacuum at 200C. Then they are reduced by dry and pure hydrogen passed over or through them at a rate between 2 liters per hour to 10 liters per hour (l/H) at temperatures between 700 and 1300C. The metal or thealloy yielded by this reduction of the complex is recovered depending on its fusion temperature and the temperature of the end of the reduction as a liquid or as a powder.
• the temperature at the end of the reduction it is necessary to bring the temperature at the end of the reduction to at least l200C to eliminate the intermediate hydride which has formed. ln the case of thorium whose hydride is even more stable, it is absolutely necessary to follow up the reduction treatment with a heating under vacuum (10' bar) at 1 C in order to decompose the hydride and yield the metal.
• the drying temperature may be in the range of l50 to 250C.
• the crystals of this cyanide complex are first dried under a stream of pure and dry hydrogen at 200C and then, still with this same hydrogen stream. the temperature is raised at a rate of 600C per hour (C/h) to lO00C.
• Example ll. Beryllium The tetracyanoberyllate of beryllium: Be[Be(CN) is prepared as in Example ll of the above mentioned patent application. The crystals of this cyanide complex are first dried under a stream of pure and dry hydrogen for several hours at 200C then, still with this same hydrogen stream, the temperature is raised at 600C/h to ll00C. This yields a powder of metallic beryllium.
• a suspension of an aluminum hydroxide gel or of a fine hydrargyllite resulting from the hydrolysis of a solution of sodium aluminate obtained by alkali solubilization of bauxite according to the Bayer process is filtered.
• the hydrate cake is carefully washed then introduced into an autoclave with an aqueous solution of hydrocyanic acid whose concentration by weight lies between l0 and 40% HCN.
• an excess of from l0 to of hydrocyanic acid relative to the quantity theoretically necessary for reaction (I) is employed.
• a mixer is used to agitate the mixture energetically and the sutoclave is heated to a temperature between 80 and l50C according to the reactivity of the hydrate, the attack on a gel using a lower temperature than that upon a wall crystallized hydrate.
• the aqueous solution of the cyanide complex can be concentrated by evaporation in a vacuum between 40 and 6020 C.
• the resulting crystals are subsequently dried in a vacuum. It is faster to perform an azectropic removal of the water with a nonmiscible liquid having a low boiling point, gasoline for example.
• This azeotropic distillation carried out under reduced pressure allows rapid recovery of the crystals of the cyanide complex without raising the temperature above 20 to 40C.
• the completely dry crystals of the cyanide complex are subjected to progressively higher temperatures in a stream of pure and dry hydrogen injected at from 2 l/h to 10 l/h until a final temperature lying between 700 and 900C is attained.
• the reduction of the complex starts at around 400C. but only is rapid between 600 and 800C. Since the final temperatures of the reduction treatment is fixed above 700C melted aluminum is recovered which makes its extraction from the apparatus very easy.
• the metallic powder obtained in effect when the reduction is carried out below the fusion point of aluminum is very finely divided and very oxidizable.
• the excess hydrogen not used in reduction carries off the hydrocyanide acid formed. This produce is extracted from the hydrogen by scrubbing with water thereby obtaining a hydrocyanic acid solution which can be used for attacking the hydrated alumina.
• the hydrogen is dried and recycled to the apparatus where the reduction is effected after admixing with a quantity to make up for that lost during reaction (ll).
• Example V Titanium
• the octacyanotitanate of titanium (lV Ti[Ti(CN ),.l is first prepared according to Example V of the abovenamed copending application.
• the crystals of this cya nide complex are first dried in a stream of pure and dry hydrogen at 200C for several hours. then, still with this same hydrogen stream, the temperature is raised 600C /h to lO00C and this latter temperature is maintained for 4 to 5 hours. This yields a hydrided titanium powder which can be subjected to a vacuum of 10 bar at l00OC to yield the pure metal.
• Example Vl Metallic zirconium
• the octacyanozirconatc of zirconium (lV ZrlZrtCN is first prepared according to the method of Example VI of the above-named copending patent application.
• the crystals of this cyanide complex are first dried as described in Example V of this application and then the temperature is raised, still with this same hydrogen stream, at 600C/h to l200C. This latter temperature is held for 4 to 5 hours.
• the intermediate hydride so produced loses its hydrogen and becomes a fine powder of metallic zirconium.
• Example Vll Thorium The octacyanothorate of thorium: Th[Th(CN)xl is first prepared according to Example Vll of the previously cited application. The crystals of this cyanide complex are dried and their temperature is raised as in Example VI of this application to l200C. This produces a thorium hydride which when subjected to a vacuum of l0 bar at l l00C yields the metal.
• Example Vlll-Production of a Metal of the Lanthanide Group (Elements of Atomic Numbers 57-71 or of Yttrium Gadolinium will be employed here for illustration but the method given below is equally applicable to any of the metals of the lanthanide group or yttrium.
• the hexacyanogadolinate of gadolinium Gd[Gd(CN).-.l is first prepared according to Example VIII of the above-cited commonlyassigned patent application. This complex is dried and heated as described in Example VI of this application to a temperature of lOOO C. The yield is a powder of metallic gadolinium Example IX. Production of an Alloy of Cobalt and Samarium SmCo Whose Magnetic Properties are Well Known for Use in Permanent Magnets The method described immediately below is equally applicable to other alloys of cobalt with any other lanthanide in any other proportion.
• the bimetallic cyanide complex having the formula H ,Sm[Co'(CN) is prepared according to the method of Example X of the above-cited application.
• the crystals of this cyanide complex are dried with hydrogen and their temperature is raised as in Example VI to l250C.
• the reduction of the complex starts at around 750C and stops at between l000 and 1 100C, but the powder of alloy SmCo is then too oxidizable so that the temperature is raised to between 1250" and l300C under hydrogen in order to agglomerate the granules of the powder by slight sintering to obtain a less oxidizable alloy.
• Example X Production of Nickel-neodymium NdNi This method is equallyusable to produce alloys of nickel with any other lanthanide or with yttrium in other proportions.
• bimetallic cyanide complex having formula H,Nd[Ni(CN) is prepared according to the method described in Example XI of the above-cited commonly assigned patent application.
• Example IX of this application The crystals of this cyanide complex are reduced exactly as in Example IX of this application to produce an alloy powder NdNi Example X1.
• Chromium-yttrium YCr This method is equally applicable for alloys of chromium with the other lanthanides or yttrium in other proportions.
• the bimetallic cyanide complex of formula La- [Y(CN).;] is prepared according to the method of Example Xlll of the above-cited copending patent application.
• Lanthanum-aluminum LaAl This method is equally applicable to the preparation of alloys of aluminum with any other lanthamide or yttrium in the proportions corresponding to those of the respective alloys.
• the bimetallic cyanide complex of formula Al[- La(CN)6] is prepared according to the method of Example XlV of the simultaneously filed above-cited patent application.
• Example XIV Production of Cobalt-samariumbarium smBa Co
• the 'trimetallie dyanide complex having formula SmBaO, I-l ,g[Co(CN) ]5 is prepared according to the method described in Example XV of the above-cited commonly assigned patent application.
• the polymetallic cyanide complex having the formula Sm Nd ,,Pr., H, [Co(CN) l is prepared according to the method described in Example XVI of the above-cited application.
• Example lX The method of Example lX above is employed to yield an alloy powder having a composition of the formula u.s o.-zs o.2s s- It is possible and within the scope of the present invention to use the same or similar process for any alloy of cobalt containing other lanthanides of yttrium in the various proportions corresponding to the alloy composition.
• a process for producing a metal or a metal alloy consisting essentially of the steps of forming a cyanide complex of at least one metal selected from the group which consists of beryllium, magnesium, aluminum, yttrium. lanthanide elements of atomic numbers 58 to 71 inclusive, zirconium, hafnium, chromium, gallium, indium, cobalt and nickel, said cyanide complex being formed by crystallizing it from an aqueous solution of ions of its components, and drying the crystals thus formed under vacuum or in a stream of hydrogen at a temperature of to 250C; and reducing said cyav nide complex with dry gaseous hydrogen at a temperature 700 to 1300C.
• A reacting an aqueous solution containing 10 to 60% by weight of hydrogen cyanide with a basic compound of at least one metal and selected from the group which consists of the hydroxides, oxides and carbonates of the metal alone or in association with the corresponding compounds of another metal;
• step (A) recovering an aqueous solution containing a metal-metal cyanide complex from step (A);
• step (B) recovering crystals of said metal-metal cyanide complex from the solution in step (B) by heating said solution at a temperature below 60C under vacuum to evaporate water.
• step (A) recovering an aqueous solution containing a metal-metal cyanide complex from step (A);
• step (B) recovering crystals of said metal-metal cyanide complex from the solution in step (B) by heating said solution at a temperature below 60C under vacuum to evaporate water.
• A reacting an aqueous solution containing 10 to 60% by weight of hydrogen cyanide with a basic compound of at least one metal and selected from the group which consists of the hydroxides, oxides and carbonates of the metal alone or in association with the corresponding compounds of another metal;
• step (A) recovering an aqueous solution containing a metal-metal cyanide complex from step (A);
• step (B) recovering crystals of said metal-metal cyanide complex from the solution in step (B) by azeotropically distilling water from said solution at a temperature of at most 40C and at reduced pressure with an azeotropic entrainer.
• a process for producing a metal or a metal alloy consisting essentially of the steps of forming a cyanide complex of at least one metal selected from the group which consists of titanium and thorium, said cyanide complex being formed by crystallizing it from an aqueous solution of ions of its components, and drying the crystals thus formed under vacuum or in a stream of hydrogen at a temperature of 150 to 250C; and reducing said cyanide complex with dry gaseous hydrogen at a temperature of 700 to l300C, the reduction being followed by heating to lOO0 and 1 C respectively at a vacuum of 10' torr.

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Cited By (15)

Citations (3)

• 1972
  • 1972-04-28 BE BE782832A patent/BE782832A/fr unknown
  • 1972-04-28 LU LU65266D patent/LU65266A1/xx unknown
  • 1972-05-03 US US250080A patent/US3909247A/en not_active Expired - Lifetime
  • 1972-05-04 CH CH664072A patent/CH546827A/fr not_active IP Right Cessation
  • 1972-05-04 GB GB2072472A patent/GB1394842A/en not_active Expired
  • 1972-05-05 CA CA141,478A patent/CA979664A/en not_active Expired
  • 1972-05-05 DE DE2222173A patent/DE2222173C3/de not_active Expired
  • 1972-05-05 NL NL7206098A patent/NL7206098A/xx unknown
  • 1972-05-05 IT IT68418/72A patent/IT960351B/it active

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