Method of producing a purified coke

Claim 1

A PROCESS FOR MANUFACTURING A PURIFIED COKE SUITABLE FOR CARBON ELECTRODE MANUFCTURER WHICH COMPRISES CRUSHING TO FINE PARTICLES A BITUMINOUS COAL CONTAINING SILICON IMPURITIES AND WHICH BECOMES PLASTIC UPON HEATING TO HIGH TEMPERATURES, SEPARATING MINERAL IMPURITIES THEREFROM BY PHYSICAL METHODS, HEATING THE COMMINUTED PARTICLES WITH A VOLATILE FLUORIDE AT A TEMPERATURE ABOVE 100* C. AND IN ANY EVENT ABOVE THE VAPORIZATION POINT OF SAID FLUORIDE BUT BELOW THE TEMPERATURE AT WHICH THE COAL BECOMES PLASTIC THEREBY REACTING THE FLUORIDE WITH THE SILICON IMPURITIES REMAINING IN THE PARTICLES AND REMOVING THE RESULTING SILICON FLUORIDES BY VOLATILIZATION AT A TEMPERATURE BELOW THAT AT WHICH THE COAL BECOMES PLASTIC AND FINALLY COKING THE PURIFIED PARTICLES THEREBY COALESCING THEM.