Production of refractory metals

Claim 1

A PROCESS FOR PURIFYING A REFRACTORY SPONGE METAL OBTAINED FROM THE REDUCTION OF THE METAL HALIDE WITH A REDUCING METAL AND CONTAINING AS IMPURITIES UNREACTED REACTANTS AND BY-PRODUCTS FROM THE REDUCTION REACTION ENTRAPPED IN THE PORES OF SAID SPONGE, SAID PROCESS COMPRISING CONDUCTING THE FOLLOWING STEPS IN A SYSTEM CONTAINING AN ATMOSPHERE OF A SHIELDING GAS, PASSING DOWNWARDLY THROUGH AN ELECTRICALLY HEATED MELTING ZONE A ROD COMPOSED OF SAID METAL AND IMPURITIES FROM THE REDUCTION REACTION, SAID IMPURITIES HAVING A BOILING POINT BELOW THE MELTING POINT OF THE METAL, MELTING THE END OF SAID ROD IN SAID ZONE OUT OF CONTACT WITH CONTAMINATING EQUIPMENT THEREBY CAUSING DROPLETS OF METAL TO FALL FROM SAID ROD AND VAPORIZATION AND EXPULSION OF THE IMPURITIES CONTAMINATING SAID METAL, WITHDRAWING VAPORIZED IMPURITIES FROM THE MELTING ZONE WHILE ALLOWING THE METAL DROPLETS TO FREE-FALL THROUGH A COOLING SPACE TO A COLLECTION ZONE BELOW WHERE DENSE, SUBSTANTIALLY SPHERICAL PARTICLES ARE OBTAINED, FURTHER COOLING THE COLLECTED METAL PARTICLES TO A TEMPERATURE AT WHICH SAID PARTICLES ARE NONREACTIVE WITH THE NORMAL ATMOSPHERE, RECOVERING PURIFIED METAL PARTICLES WITH A REDUCED SURFACE AREA FROM SAID SYSTEM, AND THEN WASHING SAID PARTICLES WITH AN AQUEOUS MEDIUM TO REMOVE RESIDUAL IMPURITIES FROM THE SURFACE OF THE PARTICLES.