Classifications

• • C—CHEMISTRY; METALLURGY
  • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
  • C25C—PROCESSES FOR THE ELECTROLYTIC PRODUCTION, RECOVERY OR REFINING OF METALS; APPARATUS THEREFOR
  • C25C3/00—Electrolytic production, recovery or refining of metals by electrolysis of melts
  • C25C3/36—Alloys obtained by cathodic reduction of all their ions
• • C—CHEMISTRY; METALLURGY
  • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
  • C25C—PROCESSES FOR THE ELECTROLYTIC PRODUCTION, RECOVERY OR REFINING OF METALS; APPARATUS THEREFOR
  • C25C3/00—Electrolytic production, recovery or refining of metals by electrolysis of melts
  • C25C3/26—Electrolytic production, recovery or refining of metals by electrolysis of melts of titanium, zirconium, hafnium, tantalum or vanadium
• • C—CHEMISTRY; METALLURGY
  • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
  • C25C—PROCESSES FOR THE ELECTROLYTIC PRODUCTION, RECOVERY OR REFINING OF METALS; APPARATUS THEREFOR
  • C25C5/00—Electrolytic production, recovery or refining of metal powders or porous metal masses
  • C25C5/04—Electrolytic production, recovery or refining of metal powders or porous metal masses from melts
• • C—CHEMISTRY; METALLURGY
  • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
  • C25C—PROCESSES FOR THE ELECTROLYTIC PRODUCTION, RECOVERY OR REFINING OF METALS; APPARATUS THEREFOR
  • C25C7/00—Constructional parts, or assemblies thereof, of cells; Servicing or operating of cells
  • C25C7/02—Electrodes; Connections thereof
• • C—CHEMISTRY; METALLURGY
  • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
  • C25C—PROCESSES FOR THE ELECTROLYTIC PRODUCTION, RECOVERY OR REFINING OF METALS; APPARATUS THEREFOR
  • C25C7/00—Constructional parts, or assemblies thereof, of cells; Servicing or operating of cells
  • C25C7/02—Electrodes; Connections thereof
  • C25C7/025—Electrodes; Connections thereof used in cells for the electrolysis of melts

Definitions

• the present invention relates to a metal refining method, in detail, a metal refining method capable of manufacturing high-purity metals by using metal oxides in an environmentally friendly and safe manner, and which can produce high-quality metals with significantly low oxygen content. It is about. Background
• Kroll process (US Pat. No. 5,035,404).
• the Kroll process is based on the chlorination process, which uses magnesium to form zirconium chloride or
• the electrolytic reduction process is being studied as an alternative to the existing crawl process, which has several advantages such as the ability to maintain the shape of the precursor and the absence of chlorine gas, but the recovered metal is still titanium. It is difficult to control oxygen concentration after the process because it is limited to some series such as tantalum and the form of recovering metal is limited to powder or porous form. It is possible to control high oxygen concentration caused by the large surface area of these products. Report on Electrolytic Reduction Using Molten Oxide Electrolytes (Antoine
• the present invention has been made to solve the above-mentioned problems of the prior art.
• the object of the present invention is to provide a method for refining metals which can produce high purity metals from metal oxides in an environmentally friendly and safe way since no chloride process is required. It is.
• Another object of the present invention is a metal which is capable of producing high purity metals from metal oxides in the air in an environmentally friendly and safe way because no chloride process is required.
• Another object of the present invention is to provide a metal refining method for producing high quality metals with a very low oxygen content from metal oxides.
• Another purpose of the present invention is to provide a relatively low temperature process for energy
• the metal refining method according to the present invention uses a first metal, which is a metal of a binary state phase metal oxide, and an electrolytic reduction using a metal cathode having an eutectic point. And an electrolytic reduction step of producing an alloy between the phosphorus two metals; and an electrolytic refining step of electrolytic refining the solidified alloy and recovering the first metal from the alloy.
• the metal refining method (I) according to one aspect of the present invention, wherein the metal cathode is a liquid metal cathode, and the metal oxide is electrolytically reduced to prepare an alloy between the liquid first metal and the second metal.
• the metal cathode is a liquid metal cathode
• the metal oxide is electrolytically reduced to prepare an alloy between the liquid first metal and the second metal.
• the metal cathode is a solid metal cathode
• the second metal is selected from the group of alkali metals and alkaline earth metals in binary state phase.
• the metal may be a metal with three metals and an eutectic point.
• step a) includes: a) electrolyzing the oxide of the lower 13 metal using an electrolyte containing an oxide of the third metal. Reducing to form a third metal and a second metal alloy in a liquid state; and a2) introducing a metal oxide, which is an oxide of the first metal, to the electrolyte to form a third metal and a low metal alloy. And converting the alloy between the two metals.
• the temperature of step al) may satisfy the following Equation 1.
• Equation 1 Tal is the temperature of step al, Te is the binary state diagram of the three metals and the second metal, the eutectic temperature, and Tm is the melting temperature of the third metal and the melting of the second metal. The temperature is relatively small.
• the silver level in step a2) may satisfy the following Equation 2.
• Equation 2 Ta2 is the silver content in step a2), and Te 'is the first metal and the second metal.
• the metal oxide may satisfy the following formula (1).
• M is a primary metal, the second metal being a metal cathode
• a metal with a standard reduction potential that is negative than the standard reduction potential X is a real number of 1 to 3
• y is a real number of 1 to 5.
• the metal oxide is zirconium oxide, hafnium oxide, titanium oxide, tinsten oxide, iron oxide, nickel oxide, zinc oxide, cobalt oxide. , Manganese oxide, Cr oxide, Tantalum oxide, Gallium oxide, Lead oxide, Tin oxide, Silver oxide, Lanthanum oxide, Cerium oxide, Praseodymium oxide, Neodymium oxide, Promethium oxide, Samarium oxide, Euro product oxide, Gadolinium oxide, Terbium oxide ⁇ Disprosium oxide, holmium oxide, erbium oxide, erlium oxide, ytterbium oxide, actinium oxide, thorium oxide, protitanium oxide, uranium oxide, tempurium oxide, plutonium oxide, americium oxide, querium oxide, verium oxide, californium oxide,
• One or more may be selected from eisinitanium oxide, fermium oxide, mendelebium oxide, nobelium oxide and a combination thereof, wherein the complex includes a solid solution.
• the electrolyte in the electrolytic reduction includes a molten salt of a halide of a metal selected from one or more of the alkali metal and alkaline earth metal groups. can do.
• the electrolyte in the reduction of the electrolysis may further include an additive which is an oxide of one or more metals selected from the group of alkali metals and alkaline earth metals. .
• a metal refining method (I) according to an embodiment of the present invention, comprising:
• the solidification of the alloy between the second metals can be cooled and solidified at a cooling rate of 20 ° C / min or less from room temperature to the room temperature at the temperature of the liquid metal cathode at the time of electrolytic reduction.
• the temperature of the liquid metal cathode may be 1100 ° C to 1200 ° C.
• the alloy between the lower 12 metals may contain more than 2.1% by weight of the primary metal.
• the metal cathode may be copper.
• the refining method (1, II) according to the present invention is an electrolytic reduction process that smelts difficult-to-refining metals (such as zirconium) (desired metals), which does not require a chloride process, and is environmentally friendly and has excellent process stability. There is this.
• the refining method (I) according to the present invention has the advantage of suppressing the dissolved oxygen amount by recovering the metal in the form of an alloy using a liquid metal cathode, especially a liquid copper cathode having a very low oxygen solubility.
• the refining method (II) uses a solid metal negative electrode having a metal negative electrode and a process point and at the same time a solid metal negative electrode having a process point with a metal selected from an alkali and alkaline earth metal group.
• the liquid precursor alloy is converted into the alloy between the metal of the metal cathode and the metal for the purpose, so that refining can be carried out with the contact with the gas inherently blocked. It has the potential to produce high-purity metals with significantly reduced residual oxygen.
• the refining method (I, II) according to the present invention uses a metal of a metal cathode, which has a metal having a positive standard reduction potential greater than that of the target metal.
• the refining method (I, II) according to the present invention is based on the process reaction, and can be processed at a lower temperature than the melting temperature of the target metal, which is energy efficient and has a simple process, which is advantageous for commercialization. To provide.
• the refining method (1, ⁇ ) according to the present invention solidifies the alloy between the metal of the metal cathode and the target metal, and conducts refining of the solid alloy to improve the efficiency and high purity of the metal. There is an advantage to manufacture.
• the refining method (I, II) according to the present invention is a metal of a metal cathode, in which the intended metal is hardly employed, and the electrolytic reduction is performed by using a metal that forms a target metal-to-metal compound. Stable and efficient reduction of solid phase alloys is possible, and thick solid phase alloys can be reduced.
• 1 is an electrolytic reduction process in a metal refining method according to an embodiment of the present invention.
• FIG. 2 illustrates an electrolytic refining process in a metal refining method according to an embodiment of the present invention.
• FIG 3 is a view illustrating an electrolytic reduction step in a metal refining method according to an embodiment of the present invention.
• 6 is a scanning electron micrograph of the structure of the different alloys obtained in the electrolytic reduction process in one embodiment of the present invention.
• FIG. 9 is a view showing the results of the X-ray diffraction test of the alloy obtained in the electrolytic reduction process in one embodiment of the present invention.
• FIG. 10 is a view showing optical photographs, scanning electron micrographs, and EDS element analysis results of observing a cathode and an anode in an electrolytic refining process according to one embodiment of the present invention, and [51] FIG. In the embodiment, a scanning electron microscope photograph of the cross section of the anode after the electrolytic refining process was performed,
• FIG. 12 is a cross-sectional view of a Cu—Zr alloy containing 1.21 wt.% Cu.
• the metal refining method according to the present invention uses a metal cathode having a eutectic point and a metal U of a binary state phase metal oxide, and through the electrolytic reduction using the metal cathode of the first metal and the metal cathode.
• the metal refining method according to the present invention can be embodied in a first embodiment using a liquid metal cathode and a second embodiment using a solid metal cathode, depending on the phase of the metal cathode during electrolytic reduction.
• the first aspect uses liquid metal cathode as a product of the electrolytic reduction process.
• the alloy between the first metal (metal of the metal oxide, the target metal to be refined) and the second metal (metal of the metal cathode) may be manufactured.
• a solid metal cathode in which an alloy of intermediate liquid is manufactured as an electrolytic reduction product, and then the alloy of the intermediate product liquid is converted into an alloy between the first metal and the second metal.
• the second aspect physically separates the continuous multistage reaction that occurs when the electrolyte of the electrolytic reduction process of the specific example of the first aspect further contains an oxide of a metal selected from the group of alkali metals and alkaline earth metals as an additive.
• This may be an embodiment in which the air process (air-heavy metal refining process) is made possible by the development thereof.
• the metal refining method according to the first aspect will be described.
• the metal cathode is a liquid metal cathode, and the metal oxide is electrolytically reduced so that an alloy between the liquid first metal and the second metal can be produced.
• the metal refining method according to the present invention uses a metal cathode having a eutectic point and a first metal, which is a metal of a binary state phase metal oxide, to reduce and reduce the raw material including the metal oxide, thereby to recover the first metal and the liquid metal.
• Challenge 1 With the binary state of the metal phase eutectic point, in the electrolytic reduction of metal oxides (oxides of the first metal), alloys between the liquid first metal and the second metal can be produced.
• the metal refining method according to the present invention is carried out to reduce and reduce the raw material containing the metal oxide, the liquid metal cathode (metallic metal chaff U metal) and process (Eutectic Phase) Of metal oxides
• the metal (primary metal) is electrolytically reduced and at the same time the eutectic reaction lowers the melting point of the metal (primary metal), it is possible to effectively reduce the electrolytic reduction at relatively low temperatures.
• the reduction metal (the first metal) is obtained in the state of (alloy of the first metal and the second metal), oxygen contamination can be prevented remarkably.
• the standard redox potential difference between the second metal, which is the metal of the liquid metal cathode, and the target metal, which is the target metal is more than that in the electrolytic refining process.
• the metal oxide can be easily reduced, i.e. when a metal having a positive standard reduction potential more than the standard reduction potential of the first metal is used as the metal of the liquid metal cathode, The standard reduction potential shifts in the positive direction, making it easier to reduce the charge on the metal.
• the metal refining method according to the present invention is a liquid phase obtained by electrolytic reduction.
• electrolytic refining of the solid phase to obtain the desired metal After solidifying the alloy, electrolytic refining of the solid phase to obtain the desired metal, a simple stacking can greatly improve the refining rate (productivity) of the intended metal.
• the electrolytic refining is carried out in the form of an ingot with excellent conductivity by solidifying the liquid alloy so that the electrolytic refining can be carried out effectively and easily without any pretreatment other than the form processing.
• electrolytic refining is performed by solidification, it is advantageous in terms of efficiency because it is easy to increase the reaction area during refining.
• a metal contained in a raw material in a method for refining metal according to an embodiment of the present invention is a metal contained in a raw material in a method for refining metal according to an embodiment of the present invention.
• the oxide may satisfy the following formula (1).
• M is a metal having a standard reduction potential of negative than the standard reduction potential of the second metal, which is the metal of the liquid metal cathode
• X is a real number of 1 to 3
• y is a real number from 1 to 5.
• the metal oxide according to Chemical Formula 1 is selected from the second metal, which is a metal of the liquid metal cathode.
• the standard metal reduction potential of the first metal is increased in a positive direction by the liquid metal cathode during the electrolytic reduction, so that even if it is difficult It can be easily reduced to a metal.
• the metal oxide may be zirconium oxide, hafnium oxide, titanium oxide, tungsten oxide, iron oxide, nickel oxide, zinc oxide, cobalt oxide, manganese oxide, chromium oxide, tantalum oxide, gallium oxide, lead oxide, Tin oxide, silver oxide, lanthanum oxide, cerium oxide, praseodymium oxide, neodymium oxide, promethium oxide, samarium oxide, euro product oxide, gadolinium oxide, terboom oxide, dysprosium oxide, holmium oxide, erbium oxide, lium oxide, ytterbium oxide, Actinium oxide, thorium oxide, protactinium oxide, uranium oxide, neptunium oxide, plutonium oxide, american oxide, querium oxide, buckleium oxide, californium oxide, ein titanium oxide, permium oxide, mendelebium oxide, nobelium oxide and one or more of these complexes More than one can be selected, The
• the metal refining method comprises the steps of selecting a metal (primary metal) to be refined; forming a eutectic phase with the selected metal (primary metal) Of metal cathodes (with binary state phase melting points)
• the step of selecting the second metal may include forming an eutectic phase with the first metal.
• the liquid metal cathode is characterized by the above-mentioned eutectic phase formation conditions and primary metals. Any metal that satisfies the condition of having a positive standard reduction potential rather than the standard reduction potential can be used. However, in order to have a process temperature as low as possible with eutectic formation, the second metal satisfies the above conditions and has a low melting point. It is advantageous to be metal.
• the electrolytic refining of the liquid alloy of the first metal and the second metal obtained in the electrolytic reduction process and then solidified As a result, the second metal, which is the metal of the liquid metal cathode, does not employ the first metal as much as possible
• the rate of electrolytic refining is determined by the rate of diffusion of system 1 metal from the center of the solidified alloy to the surface, resulting in a significant drop in the efficiency of electrolytic refining. to be.
• the step of selecting the second metal includes forming an eutectic phase with the first metal.
• It may have a positive standard reduction potential rather than the standard reduction potential, and may include selecting a metal forming the intermetallic compound as the metal (second metal) of the liquid metal cathode.
• the metal (second metal) of the liquid metal anode may be selected from one or more of Cu, Sn, Zn, Pb, Bi, Cd, and their alloys, but the present invention is based on the liquid metal cathode.
• the second metal is a heterogeneous metal which is different from the first metal.
• the refining method according to the embodiment of the present invention is directed to oxygen.
• the refining method according to the present invention is based on conventional crawling processes of zirconium or titanium. It is particularly advantageous to replace the manufacturing method, i.e., the refining method according to one embodiment of the present invention may be a refining method of zirconium or titanium, replaces the conventional crawl process, is commercially available, and minimizes contamination with oxygen. It may be a method of refining zirconium or titanium.
• It may be a metal that forms a eutectic phase with zirconium (or titanium) and has a positive standard reduction potential than that of zirconium (or titanium) and forms an intermetallic compound with zirconium (or titanium).
• copper is an example of a specific liquid metal cathode, in which zirconium (or titanium) is practically not employed, and it is advantageous to form an intermetallic compound with zirconium (or titanium) in a wide variety of compositions.
• copper is difficult to reduce the reduction of the standard reduction potential difference with zirconium (or titanium) The electrolytic reduction reaction of zirconium oxide (or titanium oxide) can be facilitated.
• the liquid metal cathode can not only prevent oxygen contamination by eutectic phase using liquid metal cathode.
• the dissolved oxygen content of copper is very low, which can significantly reduce the oxygen content of the metals obtained by alloying and / or electrolytic refining, particularly in the case of the desired metal zirconium or titanium.
• the oxygen content of the metal obtained by alloying and / or electrolytic refining can be controlled to less than 1000 ppm.
• an electrolytic reduction is a liquid metal cathode (molten metal of FIG. 1), an electrolyte. (Molten salt in FIG. 1) and electrolytic reduction aids comprising an anode (anode in FIG. 1) and a reference electrode (reference electrode in FIG. 1).
• electrolytic reduction raw materials containing metal oxides are included in the electrolyte.
• the metal oxide may be powdery, and it is advantageous for the average particle size to be ⁇ or less, specifically ⁇ to 20 ⁇ , so that it can be stably dispersed in the electrolyte.
• the electrolyte in the electrolytic reduction step may be a molten salt of a halide of a metal selected from one or more of the alkali metal and alkaline earth metal groups. More specifically, the electrolyte of the electrolytic reduction process may be Li, Na, K, Rb. And an alkali metal molten salt of an alkali metal comprising Cs and an alkali metal selected from the group of alkaline earth metals including Mg, Ca, Sr and Ba.
• the halide may be a chloride, fluoride, bromide, Iodide ' or combinations thereof. It is preferable to use salts with a higher boiling point of the electrolyte in order to melt (liquid cathode) the metal used as the cathode.
• the electrolyte in the electrolytic reduction process is a chloride. It is advantageous, and calcium chloride (CaCl 2 ) is more advantageous.
• the electrolyte of the electrolytic reduction step may further include an additive which is an oxide of one or more metals selected from the group of alkali metals and alkali earth metals.
• the content of the additive may be 0.1 to 25% by weight based on the total weight of the electrolyte.
• the oxides of one or more metals selected from the group of alkali metals and alkaline earth metals include Li 2 0, Na 2 0, SrO, Cs 2 0, K 2 0, CaO, BaO or combinations thereof. Oxides of the metals contained in the electrolyte are advantageous by allowing easier reduction of the metal oxides contained in the raw materials.
• reaction 2 is a total of two stages, in which the compound is formed by reaction of the electrolyte additive and the zirconium oxide in the first stage, and then the compound is electrolyzed and reduced in the second stage to produce the copper-zirconium alloy.
• Banung Sik 3 is a two-stage reaction, in which the calcium ion is reduced to calcium in the first stage and chemically reacts with the calcium zirconium oxide produced in the second stage to form zirconium metal, which occurs in the reaction copper copper cathode.
• Copper-zirconium alloys can be formed.
• reaction 4 is a reaction of three stages, in which the electrolyte additive and the zirconium oxide react with each other to form a compound ol, and in the second stage, after the reduction of calcium to dicalcium by electrolytic reduction, three stages Zirconium metals can be produced by chemical reactions in which electrolytic reduction processes and chemical reduction processes occur in liquid copper cathodes, and finally copper-zirconium alloys can be produced by reacting with metal zirconium and liquid copper.
• the current density during the electrolytic reduction step can cause stable electrolytic reduction.
• the current density in the electrolytic reduction step may be between 100 and 1000 mA / cm 2 , more specifically between 300 and 700 mA / cm 2 , but not limited thereto.
• the charged metal oxide may be reduced in time.
• the charge reduction step may be performed for 30 minutes to 8 hours, but the charge reduction time is performed.
• the amount of metal oxide can be adjusted appropriately, and of course, the present invention cannot be limited by the electrolytic reduction process time.
• the potential applied to the cathode is -0.3 to the hydrogen reduction potential. May be to -4V, but is not limited to this.
• a conventionally used positive electrode or reference electrode may be used.
• graphite may be used as the positive electrode
• W pesudo
• the present invention may be a positive electrode or a reference electrode.
• it can not be limited by the substance.
• the process temperature of the electrolytic reduction process is based on the melting point of the electrolyte and the melting point of the liquid metal cathode.
• the temperature is 200 o C.
• the electrolyte is CaCl 2 molten salt and the metal used as the cathode is copper, the process of electrolytic reduction can be from 1100 ° C to 1200 ° C.
• the alloy preferably contains a primary metal of 2.1 weight ⁇ 3 ⁇ 4 or more, more preferably 7 weight%, even more preferably 16 weight of 1 3 ⁇ 4 or more of the primary metal.
• the cathode is converted to a liquid phase alloy. Subsequently, when the liquid phase alloy is solidified and the electrolytic refining of the solid alloy is carried out, when the first metal contained in the liquid phase alloy is less than 2.1% by weight, the continuous material movement path of the system 1 metal in the solid phase alloy There is a risk that the electrolytic refining itself will not be substantially formed.
• the phase alloy is the first metal, which is the metal of the liquid metal cathode, as it is a liquid alloy.
• the two metal phases of the intermetallic phases of the first metal and the second metal have a common microstructure, where the content of the base metals in the alloy is less than 2.1% by weight.
• the structure of the alloy may be a structure in which intermetallic compounds of the first metal and the second metal are dispersed in a matrix of a system of one metal in an island form. In this case, electrolytic refining of solid alloy 2 Metals are trapped in a matrix and there is a limit to the difficulty of escaping out of solid alloys.
• the liquid alloy contained at least 2.1% by weight of the first metal, thereby obtaining a solid phase.
• the intermetallic phases of the first metal and the second metal are connected to each other continuously to provide a material movement path of the second metal.
• Electrolytic refining can be done.
• the liquid phase alloy is 2.1% by weight so that intermetallic compounds of the first metal and the second metal formed at grain boundaries or triple points of the first metal grain can stably reach a continuum. It is preferable to contain the above primary metals, and more preferably to contain at least 7% by weight of primary metals.
• the intermetallic compound grains of the first metal and the second metal can be formed by themselves without passing through grain boundaries of the first metal grain or the triple point.
• the liquid alloy preferably contains at least 16% by weight of the primary metal so that the intermetallic compound can stably form a continuum, wherein the upper limit of the first metal content in the actual liquid alloy can be 70% by weight.
• the first metal content in the alloy is the mass and charge reduction of the liquid metal cathode.
• the metal oxide injected into the electrolyte can be controlled by controlling the mass and, independently of this, by controlling the time the electrolytic reduction is carried out.
• the metal oxide metal in the electrolytic reduction metal cathode is As the liquid metal cathode is reduced to alloy, the metal oxide injected into the electrolyte during electrolytic reduction is the sum of the metal (first metal) of the introduced metal oxide and the metal (second metal) used as the cathode of the electrolytic reduction.
• the metal content of the metal oxide (primary metal) of the metal oxide can be controlled so that the weight of the primary metal in the alloy is not less than 1 wt ⁇ 3 ⁇ 4, preferably 7 wt%, more preferably 16 wt% or more.
• a certain amount of metal oxide can be added to the electrolyte and then the time required for the reduction of the electrolysis to control the first metal content in the alloy.
• cooling may be carried out for the solidification of the liquid phase alloy, in which the liquid phase alloy is solidified by the cooling rate of the liquid phase alloy, as the first metal and the second metal are homogeneously common. Afterwards, the structure of the alloy obtained is greatly influenced.
• the cooling rate can be stably formed between intermetallic phases, and a structure in which the intermetallic compound phases of a metal and a second metal are continuously connected to each other.
• the cooling rate may be at least substantially l ° C / min or more, and more substantially 5 ° C / min.
• the present invention is not limited to solidification by direct quenching of the liquid alloy obtained from electrolytic reduction. Specifically, after solidifying the liquid alloy obtained from electrolytic reduction, the powder of solidified alloy is removed.
• the method may further include molding the alloy into a designed shape suitable for electrolytic refining, such as by using molding and heat treatment or casting using a molten liquid (re-melt) of the solidified alloy, and cooling at 20 ° C / min or less in this forming step Cooling can be carried out at a rate, i.e., the slow cooling described above can also be achieved in the manufacture of solid alloys used for electrorefining.
• the electrolytic refining step of solidifying the alloy to obtain a high phase alloy, electrolytic refining of the solid alloy, and recovering the base metal from the alloy may be performed.
• the remaining electrolyte is removed from the product obtained in the electrolytic reduction step.
• the removal of the residual electrolyte may include thermal distillation of the electrolyte by heat treatment in a vacuum or inert gas atmosphere of the product obtained in the electrolytic reduction step.
• the distillation temperature heat treatment temperature
• the melting point temperature of the electrolyte used in the electrolytic reduction step is acceptable. In one example, the distillation temperature can be between 780 and 900 ° C, but is not limited thereto.
• the residual electrolyte removal process is a product obtained in the electrolytic reduction step (solidified alloy). As it is carried out in the solid state, it is not necessary to specifically control the angular velocity when performing the residual electrolyte removal process on the product obtained by the above-mentioned slow cooling.
• FIG. 2 is a flowchart illustrating a process in which electrolytic refining is performed in a refining method according to an embodiment of the present invention.
• electrolytic refining is obtained by solidification of an electrolytic refining process. It can be carried out in an electrolytic refining bath comprising an anode (anode in FIG. 1), an electrolyte (molten salt in FIG. 2) and a cathode (cathode in FIG. 2) and a reference electrode (reference electrode in FIG. 2).
• the electrolyte in the electrolytic refining is independent of the electrolyte in the electrolytic reduction step described above.
• It may be a molten molten salt of one or more metals selected from the group of alkali metals and alkaline earth metals. More specifically, the electrolytes of the electrorefining process are alkali metals and Mg including Li, Na, K, Rb and Cs. Of one or more metals selected from the group of alkaline earth metals, including Ca, Sr and Ba
• the halide may be a molten molten salt, wherein the halide may comprise a chloride, fluoride, bromide, iodide or a combination thereof.
• the electrolyte of the electrolytic refining process is preferably one or more selected from LiCl, KC1, SrCl 2 , CsCl, NaCl, LiF, KF, SrF 2 , CsF, CaF 2 and NaF.
• more than one salt may form a eutectic salt.
• the electrolyte of the electrolytic refining process may include lithium halides and small halides, and more specifically, the electrolyte of the electrolytic refining process may include lithium fluoride and potassium fluoride.
• the temperature of the electrolytic refining process may be 600 to 800 ° C, but not limited thereto.
• the electrolytic refining process is composed of zirconium fluoride (ZrF 4 ) and The same additive may further be included, and the additive may be contained in an amount of 1 to 10% by weight based on the total weight of the electrolyte.
• the current density during the electrolytic refining step can cause stable electrodeposition of the primary metal.
• the current density in the electrolytic refining step may be 10 to 500 mA / cm 2 , more specifically 50 to 200 mA / cm 2 , but is not limited thereto. , Specifically limited But it can be done for 1 to 20 hours.
• the cathode or reference electrode is used for electrorefining metals.
• cathode or reference electrode that is commonly used may be used.
• stainless steel or the like may be used as the cathode.
• W pesudo or the like may be used as the reference electrode, but the present invention may not be limited by the cathode or the reference electrode material.
• the metal cathode (second metal) is a solid metal.
• the second metal may be a metal having a eutectic point with a third metal, which is a metal selected from one or more of the binary state alkali metal and alkaline earth metal groups.
• the metal refining method according to the present invention has a eutectic point with the low 11 metal of the binary state phase metal oxide and at the same time, one or two of the binary state alkali metal and alkali earth metal groups.
• an electrolytic refining step of electrolytic refining the solidified alloy to recover the system metal from the alloy.
• a metal refining method according to the present invention and an embodiment includes alkali metals and
• the electrolyte further contains an additive which is an oxide of a metal (third metal) selected from one or more of the alkali metal and alkaline earth metal groups, it is lower by indirect reduction. Cathode applied than at potential
• Reaction intermediates containing metals (third metals) belonging to the alkaline earth metal group are less dense than the electrolytes used in the electrolytic reduction process and can therefore be sludge-like.
• the floating metal (third metal) comes into contact with the atmosphere, which, when the atmosphere contains oxygen, such as air, is injured and the intermediate products are oxidized and the reduction efficiency can be reduced.
• oxygen such as air
• the second aspect is a method in which an atmospheric charge reduction process can be performed while maintaining the advantages of indirect reduction (high reduction efficiency at low voltage conditions).
• FIG. 3 is a flowchart illustrating a process in which electrolytic reduction is performed in a refining method according to an embodiment of the present invention.
• the electrolytic reduction includes a solid metal cathode (cathode, M2 of FIG. 3), an electrolyte (molten salt of FIG. 3), an anode (anode of FIG. 3) and a reference electrode (reference electrode of FIG. 3).
• the electrolyte includes an oxide of a metal (third metal) belonging to the alkali metal and alkaline earth metal group (oxide of M3 in FIG. 3), but the metal oxide is a raw material. It may not contain (oxides of the first metal).
• a third metal (M3 in FIG. 3) may be electrodeposited on the surface.
• the material of the metal cathode has a eutectic point with the binary state phase third metal, and thus the third metal is reduced and electrodeposited on the metal cathode surface.
• the supersolid metal cathode may react with each other to form a liquid intermetallic third and second metal alloy (M2M3 liquid droplet in FIG. 3).
• the droplets of the resulting alloy between the third and second metals are denser than the electrolyte used in the electrolytic reduction process and can be deposited on the bottom of the electrolytic reduction bath.
• the contact of trimetals, M3) or products (M2M3 liquid) with atmospheric oxygen may be blocked at the source.
• the electrolytic reduction process can be carried out in air.
• Oxides of one or more metals (third metal) selected from the group of alkali metals and alkaline earth metals contained in the electrolyte are Li 2 0, Na 2 0, SrO, Cs 2 0, K 2 0, CaO, BaO or these
• the oxide of the third metal provides a strong reducing power, produces a dense base metal and a second metal alloy, and provides CaO, which can be carried out at a relatively low temperature in the electrolytic reduction process.
• the electrolyte may contain, but is not limited to, an oxide of 0.1 to 25% by weight, based on the total weight of the electrolyte.
• the electrolyte may be a molten salt of a halide of a metal selected from one or more of the alkali metal and alkaline earth metal groups. More specifically, the electrolyte of the electrolytic reduction process is an alkali metal comprising Li, Na, K, Rb and Cs. And molten salts of a halide of one or more metals selected from the group of alkaline earth metals including Mg, Ca, Sr and Ba.
• the halides can be chlorides, fluorides, bromide, iodides or traces thereof. May contain mixtures.
• the process is stable in the diagram and the electrolyte in the electrolytic reduction process is advantageously chloride and chlorine chloride (CaCl 2 ) in terms of being able to be layered with the third metal and the second metal alloy (liquid phase) stably due to density differences. It is more advantageous.
• the metal cathode has a binary state eutectic point of the second metal and a third metal, and simultaneously satisfies the condition of having a binary state eutectic point of the first metal and the second metal.
• Any metal that does not belong to the alkali and alkaline earth metals can be used, and it is advantageous to be a metal that satisfies the condition of having a positive standard reduction potential rather than the quasi-reduction potential of the first metal.
• Electrolytic refining is carried out, whereby the second metal, which is the metal of the liquid metal cathode, is advantageously a metal which does not employ the first metal as much as possible and forms an intermetallic compound with the first metal. If a solid solution is formed with the primary metal or the solubility limit of the primary metal is high, the rate of electrolytic refining is increased by the rate of diffusion of the primary metal from the center of the solidified alloy to the surface. Determined, there is a risk that the efficiency of electrorefining will drop significantly.
• the second metal forms eutectic points with the binary state phase 3 metals, forms eutectic points with the binary state phase 1 metals, and simultaneously reduces the standard reduction potential of the first metal. It is advantageous to have a positive standard reduction potential than the standard reduction potential of the first metal, and to form a metal that forms a compound between the first metal and the metal.
• Secondary metals are binary, at least, second metals; between the U metal and the second metal.
• Intermetallic compounds an eutectic point can be located between them.
• the metal (second metal) of the liquid metal anode may be selected from Cu, Sn, Zn, Pb, Bi, Cd, and alloys thereof, but the present invention may be selected by the liquid metal cathode. It is to be understood that the base metal is different from the first metal and is one or more metals selected from Cu, Sn, Zn, Pb, Bi, Cd and their alloys.
• the refining method according to one embodiment of the present invention can minimize contamination (oxygen impurity) to oxygen and reduce the electrolysis at a temperature relatively lower than that of the first aspect.
• contamination oxygen impurity
• the refining method according to the present invention is particularly advantageous to replace the production method with zirconium or titanium based on the conventional crawl process.
• the refining method according to the present invention may be a refining method of zirconium or titanium, and may replace a conventional bulk process, commercialize, minimize oxygen contamination, and may be refining method of zirconium or titanium in air.
• the metal cathode is in phase It may be a metal having a process point with zirconium (or titanium) and having a positive standard reduction potential than that of zirconium (or titanium) and forming an intermetallic compound with zirconium (or titanium).
• copper is an example of a specific metal cathode, which does not substantially employ zirconium (or titanium), and is advantageous in that it forms an intermetallic compound with zirconium (or titanium) in a wide variety of compositions.
• copper has a standard reduction potential difference with zirconium (or titanium). Reduction reactions of zirconium oxides (or titanium oxides) by trimetals can be facilitated.
• the temperature can satisfy the following equation.
• Equation 1 Tal is the temperature of al) step (° C)
• Te is the binary state diagram of the third metal and the second metal
• Tm is the third metal.
• the melting temperature and the melting temperature of the second metal ( 0 C) are relatively small and the melting temperature of the third metal.
• Te of 1 may be the lower of the process temperatures of two or more process points.
• Equation 1 The temperature of Equation 1 is the metal cathode and retains the phase at the time of electrolytic reduction.
• the temperature at which the alloy between the liquid third metal and the second metal can be formed by the process reaction between the three metals and the solid metal cathode electrodeposited on the cathode.
• Tal may be Te ⁇ Tal ⁇ 1.4Tm, more advantageously Te ⁇ Tal ⁇ 1.3Tm, where the upper limit of Tal temperature, as shown in Equation 1, is higher than the melting temperature Low is, of course.
• the temperature of the electrolytic reduction of FIG. 3 may be 750 to 1100 ° C., advantageously 800 to 900 ° C.
• the current density during the electrolytic reduction step can cause stable electrolytic reduction.
• the current density in the electrolytic reduction step can be 1 to 100 mA / cm 2 , more specifically 200 to 600 mA / cm 2 , but this is not limiting. Of course, it can be properly adjusted in consideration of the amount of the oxide of the tertiary metal, and the present invention can not be limited by the time of the electrolytic reduction process.
• the potential applied to the cathode during the electrolytic reduction step is a stable reduction reaction As a specific example, the potential applied to the cathode may be -0.3 to -4V relative to the hydrogen reduction potential, but is not limited thereto.
• the anode or reference electrode A positive electrode or a reference electrode commonly used for the electrolytic reduction of metal oxides may be used. As a specific and non-limiting example, graphite may be used as the anode, and W (pesudo) may be used as the reference electrode. Of course, the invention cannot be limited by the anode or reference electrode material.
• FIG. 4 is a flowchart illustrating a process of converting an alloy between a third metal and a second metal, which is a product of electrolytic reduction, into an alloy between the first metal and a second metal, in a refining method according to an embodiment of the present invention.
• the raw material is added to the electrolyte of the electrolytic reduction aid.
• a metal oxide (oxide of the first metal) may be introduced to convert the alloy between the third metal and the second metal into an alloy between the first metal and the second metal.
• the alloy between the third metal and the second metal The first metal and the second metal
• the reaction that is converted to the alloy of the metal may be a voluntary reaction, as the metal belonging to the alkali metal and alkali earth metal group has the strongest reducing power among the metals, reducing the metal oxide of the third metal as the raw material and This is because alloys between metals (liquid alloys) are produced and themselves (third metal) can be oxidized to metal oxides.
• the temperature at which the conversion process is performed is equal to that of the second metal.
• the temperature at which the conversion step is carried out can satisfy the following equation.
• Equation 2 Ta2 is the temperature of step a2), and Te 'is the temperature of the first metal and the second metal.
• the binary state diagram, the eutectic temperature, and Tm ' is the melting temperature of the second metal. If the binary states of the first and second metals have more than one process point, T in relation 2 is the The process may be at a relatively low temperature during the process.
• the temperature of the conversion step can be carried out at temperatures exceeding the eutectic temperature of the binary metals of the first and second metals and, preferably, are located closest to the second metal (the pure second metal). It is advantageous to be carried out at a temperature higher than the eutectic temperature of the eutectic point. Also, as shown in Equation 2, the temperature of the transition stage is determined by the melting temperature (Tm ', 0 C) of the second metal. It can be carried out at temperatures below 1.5 Tm ', because there is a risk that the conversion efficiency will be reduced if the temperature of the transition stage is excessively high. In an exemplary embodiment, when the second metal is copper and the metal zirconium is to be refined, the advantageous temperature at which the conversion process of FIG.
• the conversion process to the alloy between the first metal and the second metal is based on voluntary reactions, as shown in FIG. 4, the electrodes (cathodes, anodes, reference electrodes, etc.) embedded in the electrolytic reduction aid during electrolytic reduction are removed.
• metal oxide as a raw material may be introduced, but of course, removal of the electrode may be selectively performed.
• the metal oxide (oxide of the first metal) introduced into the electrolyte of the electrolytic reduction tank may satisfy the following formula (1). '
• M is the first metal to be reduced metal
• X is a real number of 1 to 3
• y is a real number of 1-5.
• the metal oxide may be zirconium oxide, hafnium oxide, titanium oxide, tungsten oxide, iron oxide, nickel oxide, zinc oxide, cobalt oxide, manganese oxide, cream oxide, tantalum oxide, gallium oxide, lead oxide, Tin oxide, silver oxide, lanthanum oxide, cerium oxide, praseodymium oxide, neodymium oxide, promethium oxide, samarium oxide, euro product oxide, gadolinium oxide, terbium oxide, dysprosium oxide, holmium oxide, erbium oxide, tlium oxide, ytterbium oxide, actinium One or two of oxides, thorium oxides, proctininium oxides, uranium oxides, neptunium oxides, plutonium oxides, american oxides, curium oxides, buckleium oxides, californium oxides, eincitanium oxides, permium oxides, mendelebium oxides, nobelium
• Solidification of the alloy described above and similar alloys in the manufacturing method can be carried out, and electrolytic refining can be performed in the same manner as the electrolytic refining step described in the manufacturing method of the first aspect.
• the current density of the electrolytic reduction process was 500 mA / cm 2 , and the cathode potential was Was -1.3 ⁇ -1.5V compared to tungsten reduction potential, and the electrolytic reduction process was 9 hours, 1.6 hours, Was carried out for 3.3 hours or 6.5 hours.
• a Zr-Cu alloy containing 3.2% by weight of zirconium (hereinafter referred to as 3% Zr-Cu alloy) was produced when electrolytic reduction was carried out for 0.9 hours, and 7.49 weight when electrolytic reduction was carried out for 1.6 hours. It was confirmed that a Zr-Cu alloy containing% zirconium (hereinafter referred to as 7% Zr-Cu alloy) was produced, and a Zr-Cu alloy containing 16.42 wt% zirconium after 3.3 hours of electrolytic reduction was performed. 16 Zr-Cu alloys) were produced, and Zr-Cu alloys (hereinafter referred to as 27 Zr-Cu alloys) containing 27.47% by weight of zirconium when electrolytic reduction was performed for 6.5 hours. It was confirmed.
• the oxygen concentration of the 3% Zr-Cu alloy was 142 ppm
• the oxygen concentration of the 7% Zr-Cu alloy was 132 ppm, 16 Zr-Cu.
• the oxygen concentration of the alloy was 223 ppm
• the 27% Zr-Cu alloy was found to have an oxygen concentration of 249 ppm—all alloys and oxygen concentration levels: less than aOOppm. It was confirmed.
• the Cu-Zr intermetallic compounds were formed at grain boundaries of copper.
• FIG. 9 is a diagram showing the results of X-ray diffraction analysis of 7% Zr-Cu alloy (red graph of FIG. 9) and 27% Zr-Cu alloy (black graph of FIG. 9). know as with copper, this alloy consisting of CuZr uigeum of the intergeneric compound (CuZr, Cu 5 Z ri, Cu 0 .44Zr 0 565) we can see Preparation doemol.
• Electrolytic refining was carried out for 10 hours at a current density of 100 mA / cm 2 .
• FIG. 11 is a scanning electron microscope photograph of the cross section of the anode after 10 hours of electrolytic refining.
• a zirconium lean region is formed from the surface to the center as zirconium is released.
• the zirconium thinning zone gradually progresses toward the center of the anode, which provides a stable migration path of zirconium between the centers in the zirconium thinning zone even if zirconium escapes from the anode surface.
• the continuum of copper alloys zirconium-copper intermetallics
• Zirconium is also a zirconium thinner region by analyzing EDS 10 random regions in the anode cross section of 11. As a result of measuring the composition of the surface area and the internal center area, the average zirconium content of the zirconium foil area is
• the electrolytic reduction process was carried out to experimentally examine the effect of the zirconium migration pathway provided by the zirconium-intermetallic compound. After the Zr-Cu alloy containing 1.2 wt% zirconium was obtained by controlling the process time, the same electrolytic refining test was performed.

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