Process for the preparation of cyanates of alkalimetals from urea and alkaline nitrites

Claim 1

A PROCESS OF PREPARING ALKALI METAL CYANATES COMPRISING MIXING UREA AND ALKALI METAL NITRITE IN THE DRY STATE IN A RATIO OF ABOUT 2 MOLS OF UREA FOR 1 MOL OF ALKALI METAL NITRITE, CONTACTING SAID MIXTURE, PORTIONWISE, ONTO AN INERT HEATED SOLID SURFACE MAINTAINED AT A TEMPERATURE OF ABOUT 210-220* C. FOR A SUFFICIENT PERIOD OF TIME TO HEAT SAID MIXTURE TO THE TEMPERATURE OF SAID SOLID SURFACE AND UNTIL THE EVOLUTION OF AMMONIA FROM SUCH HEATING CEASES, THEREAFTER COLLECTING THE PRODUCT WHICH HAS BEEN CONTACTED AT SAID SOLID SURFACE AND MIXING IT WITH AN ADDITIONAL SMALL QUANTITY OF UREA, HEATING THE MIXTURE IN A VITREOUS CRUCIBLE AT A TEMPERATURE OF ABOUT 180-190* C. UNTIL AMMONIA IS NO LONGER EVOLVED THEREFROM, RAISING THE TEMPERATURE OF THE SO-HEATED MIXTURE TO ABOUT 530* C., AND GRINDING THE MIXTURE AT A TEMPERATURE OF ABOUT 530* C. FOR SUFFICIENT PERIOD OF TIME TO PROVIDE A TEST OF AN AQUEOUS SOLUTION OF THE SO-TREATED MIXTURE WITH A COBALT NITRATE SOLUTION TO GIVE A CLEAR BLUE SOLUTION AND TO THEREBY OBTAIN A CRYSTALLINE PRODUCT OF A HIGH DEGREE OF PURITY.