Method for the production of metal powders or metal hydride powders of the elements ti,zr, hf,v,nb.ta and cr

Abstract

A method for the production of metal powders or metal hydride powders of the elements Ti, Zr, Hf, V, Nb, Ta and Cr is disclosed, whereby an oxide of the said elements is mixed with a reducing agent and said mixture, optionally with a hydrogen atmosphere (for the production of metal hydrides), is heated until the reduction reaction commences, the reaction product is quenched, then washed and dried. The oxide used has an average particle size of 0.5 to 20 ?m, a BET specific surface of 0.5 to 20 m 2 /g and a minimum content of 94 wt. %.

1 - 21 . (canceled)  
   
   
       22 . A process for preparing a metal powder or a metal hydride powder an oxide of at least one of Ti, Zr, Hf, V, Nb, Ta and Cr with a reducing agent and heating mixture in an oven, optionally under an atmosphere of hydrogen until a reduction reaction starts, and leaching the reaction product; and 
 washing and drying the resultant product to yield the metal powder or metal hydride powder, wherein the oxide has a mean particle size of 0.5 to 20 μm, a BET specific surface area of 0.5 to 20 m 2 /g and a minimum content of 94 wt. %.    
   
   
       23 . A process according to  claim 22 , wherein the mixture is heated to 800 to 1400° C. in an oven.  
   
   
       24 . A process according to  claim 22 , wherein the oxide has a mean particle size of 1 to 6 μm.  
   
   
       25 . A process according to  claim 22 , wherein the oxide has a BET specific surface area of 1 to 12 m 2 /g.  
   
   
       26 . A process according to  claim 25 , wherein the oxide has a BET specific surface area of 1 to 8 m 2 /g.  
   
   
       27 . A process according to  claim 22 , wherein the oxide has a minimum content of 96 wt. %.  
   
   
       28 . A process according to  claim 27 , wherein the oxide has a minimum content of 99 wt. %.  
   
   
       29 . A process according to  claim 22 , wherein the proportion of Fe and Al impurities in the oxide are each <0.2 wt. %, calculated as the oxides.  
   
   
       30 . A process according to  claim 29 , wherein the proportion of Fe and Al impurities in the oxide are each <0.1 wt. %, calculated as the oxides.  
   
   
       31 . A process according to  claim 22 , wherein the proportion of Si impurities in the oxide is <1.5 wt. %, calculated as SiO 2 .  
   
   
       32 . A process according to  claim 31 , wherein the proportion of Si impurities in the oxide is <0.3 wt. %, calculated as SiO 2 .  
   
   
       33 . A process according to  claim 22 , wherein the proportion of Na impurities in the oxide is <0.05 wt. %, calculated as Na 2 O.  
   
   
       34 . A process according to  claim 22 , wherein the proportion of P impurities in the oxide is <0.2 wt. %, calculated as P 2 O 5 .  
   
   
       35 . A process according to  claim 22 , wherein the loss on ignition of the oxide at 1000° C. as constant weights is <1 wt. %.  
   
   
       36 . A process according to  claim 22 , wherein the tamped down bulk density according to EN ISO 787-11 (previously DIN 53194) of the oxide is 800 to 1600 kg/m 3 .  
   
   
       37 . A process according to  claim 22 , wherein a proportion of up to 15 wt. % of said oxide is replaced by an additive selected from the group consisting of MgO, CaO, Y 2 O 3  and CeO 2 .  
   
   
       38 . A process according to  claim 22 , comprising reacting a reducing agent comprising an alkaline earth metal, alkali metal, or a hydride thereof with a compound to reduce the compound.  
   
   
       39  A process according to  claim 38 , wherein the reducing agent comprises at least one of Mg, Ca, CaH 2  or Ba.  
   
   
       40 . A process according to  claim 22 , wherein the reducing agent has a minimum content of 99 wt. %.  
   
   
       41 . A process according to  claim 22 , wherein the reaction is performed under a protective gas.  
   
   
       42 . A process according to  claim 22 , wherein the reaction product is leached with hydrochloric acid.  
   
   
       43 . A process according to  claim 23 , wherein the oxide used has a mean particle size of 1 to 6 μm.