Method for the conversion of crystalline silica raw materials into amorphous silica

In a process for the conversion of particulate crystalline silica into an amorphous silica mass by charging a furnace with the particulate crystalline silica and heating the charge to a temperature within the range of from about 1,728.degree. to about 1,900.degree. C. for a period of time sufficient to melt and convert the silica to the amorphous state while evacuating the furnace to draw off gaseous by-products and rotating the furnace at a speed sufficient to cause the silica charge to be forced against the furnace wall, wherein the furnace is a vertically mounted rotatable electric furnace provided with a central internal resistance heating element and with a cylindrical body portion having an interior surface defining an interior of a configuration approximating a truncated cone, the base of the cone defining a bottom discharge opening, the improvement comprising:

• cooling the amorphous silica mass within the furnace to a temperature within the range of 1,300.degree.-1,400.degree. C. to rigidify the mass and then rapidly discharging said cooled rigid mass through the furnace bottom by gravity to permit more rapid cooling.