Phosphorus furnace improvements

Abstract From the Canadian patent

A method of closing phosphorus furnace tapholes which comprises applying pneumatic pressure at the taphole opening to force molten material in the boretube back into the furnace and then introducing sand particles through the taphole to meet and effect solidification of incoming molten furnace material thereby sealing off the inner opening of the boretube and filling the remainder of the boretube with sand. Tapping is readily accomplished by blowing out the loose sand and breaking the inner seal of solidified furnace material.