Method for obtaining a refractory metal

Abstract

A process is provided for recovering a refractory metal. A comminuted precursor material includes the refractory metal to be recovered in oxidically bound form. A reactant of loose solids includes a slag former having a higher O2 affinity than the refractory metal. A heat-resistant reaction vessel is filled with a charge of a mixture of the precursor material and the reactant. The process triggers an exothermic redox reaction of the charge, while an inertia force acts on the reaction vessel. The charge is melted, whereby the molten refractory metal and the slag are separated owing to the inertia force that acts on the vessel during the exothermic redox reaction. The reaction vessel with at least the reaction products is cooled. Reaction products are removed from the reaction vessel, and the refractory metal is separated from the slag.

1 . A process for recovering a refractory metal, in which the refractory metal is recovered from a precursor material by a redox reaction which is exothermic in terms of its energy balance, the process comprising:
 providing a comminuted precursor material comprising the refractory metal to be recovered in oxidically bound form;   providing a reactant that reacts exothermically after ignition as reactant loose solids, wherein the reactant comprises a slag former having a higher O 2  affinity than the refractory metal to be recovered;   providing a loose solids/material mixture from the comminuted precursor material and the reactant;   filling a heat-resistant reaction vessel with a charge of the loose solids/material mixture, leaving a pore volume;   reducing the pore volume of the charge by compacting the charge by introduction of mechanical vibrations;   applying an inertia force that acts on the reaction vessel with contents of the reaction vessel;   triggering the exothermic redox reaction of the charge while the inertia force is acting thereon by a local supply of thermal energy to the charge, beginning from an edge of the charge, hence melting the refractory metal to be recovered and separating molten refractory metal from slag owing to the inertia force that acts during the exothermic redox reaction;   ending the inertia force that acts on the reaction vessel and the contents of the reaction vessel after the redox reaction has concluded; and   cooling the contents of the reaction vessel and then removing reaction products from the reaction vessel and separating recovered refractory metal from the slag.   
     
     
         2 . A process for recovering a refractory metal, in which the refractory metal is recovered from precursor material by a redox reaction which is exothermic in terms of its energy balance, the process comprising:
 providing a comminuted precursor material comprising the refractory metal to be recovered in oxidically bound form;   providing a reactant that reacts exothermically after ignition as reactant loose solids, wherein the reactant comprises a slag former having a higher O 2  affinity than the refractory metal to be recovered;   providing a loose solids/material mixture from the comminuted precursor material and the reactant;   filling a heat-resistant reaction vessel with a charge of the loose solids/material mixture, leaving a pore volume;   applying an inertia force that acts on the reaction vessel with contents of the reaction vessel;   triggering the exothermic redox reaction of the charge while the inertia force is acting thereon by a local supply of thermal energy to the charge, beginning from the an edge of the charge, hence melting the refractory metal to be recovered and separating molten refractory metal from slag, which is at least partly molten as a result of the input of heat, owing to the inertia force that acts during the exothermic redox reaction;   ending the inertia force that acts on the reaction vessel and the contents of the reaction vessel after the redox reaction has concluded; and   cooling the contents of the reaction vessel and then removing reaction products from the reaction vessel and separating molten refractory metal from the slag.   
     
     
         3 . The process as claimed in  claim 2 , wherein filling of the reaction vessel with the charge of the loose solids/material mixture is followed by reducing the pore volume of the charge by compaction thereof by introduction of mechanical vibrations. 
     
     
         4 . The process as claimed in  claim 1 , wherein the precursor material for provision of the comminuted precursor material is comminuted to a grain size between 10 μm and 500 μm. 
     
     
         5 . The process as claimed in  claim 1 , wherein the reactant has a grain size between 50 μm and 500 μm. 
     
     
         6 . The process as claimed in  claim 1 , wherein the loose solids/material mixture is provided by mixing the comminuted precursor material and the reactant in a closed mixing vessel. 
     
     
         7 . The process as claimed in  claim 1 , wherein the charge after the reducing of the pore volume is left with a pore volume of 10% to 30% in the reaction vessel before being subjected to the subsequent process steps. 
     
     
         8 . The process as claimed in  claim 1 , wherein the charge is introduced into the reaction vessel in a grading with regard to different constituents of the charge. 
     
     
         9 . The process as claimed in  claim 1 , wherein the inertia force applied to the reaction vessel is less than 350 G. 
     
     
         10 . The process as claimed in  claim 9 , wherein the inertia force is applied using a centrifuge having multiple reaction vessel holders in pairs arranged diametrically opposite one another with regard to an axis of rotation. 
     
     
         11 . The process as claimed in  claim 1 , wherein the exothermic reaction is triggered by a resistance heating element and/or by a laser beam. 
     
     
         12 . The process as claimed in  claim 1 , wherein the reaction vessel, in a section in which the molten refractory metal collects during the exothermic redox reaction, simultaneously serves as an originally forming collecting volume for the refractory metal to be recovered in which the molten refractory metal hardens, forming a casting of a cavity of the collecting volume. 
     
     
         13 . The process as claimed in  claim 12 , wherein the reaction vessel is filled such that, rather than the collecting volume which is connected thereto and is provided for collection of the molten metal being filled with the loose solids/material mixture, only a volume present in a direction of an introduction opening is filled, with the collecting volume kept clear using a loose solids/material mixture barrier that allows the molten refractory metal through for separation of the charge from the collecting volume. 
     
     
         14 . The process as claimed in  claim 13 , wherein the loose solids/material mixture barrier comprises a heat-resistant material. 
     
     
         15 . The process as claimed in  claim 13 , wherein the loose solids/material mixture barrier comprises a metal which is also present in the refractory metal to be recovered or comprises the refractory metal to be recovered. 
     
     
         16 . The process as claimed in  claim 1 , wherein the reactant is simultaneously the slag former. 
     
     
         17 . The process as claimed in  claim 1 , wherein the reactant comprises a slag former. 
     
     
         18 . The process as claimed in  claim 1 , wherein the reactant includes one or more elements from a group of elements consisting of Al, Mg and Si. 
     
     
         19 . The process as claimed in  claim 1 , wherein the exothermic redox reaction of the charge is triggered in different places in the reaction vessel. 
     
     
         20 . The process as claimed in  claim 6 , wherein the loose solids/material mixture is provided by mixing the comminuted precursor material and the reactant in the closed mixing vessel without introducing energy into the material to be mixed.