Method and apparatus for thermal treatment

An apparatus for thermal treatment of pumpable or blowable materials comprising:

• a sealed receptacle adapted to contain a high temperature smelt;
• a pair of concentrically arranged electrodes extending into said receptacle, said electrodes defining a gap therebetween, the gap being open to the interior of said receptacle at the end of said electrodes;
• means for establishing an electric arc in the gap;
• means for introducing pumpable or blowable materials into the gap a predetermined distance from the open end of the gap, whereby thermal treatment of the materials can take place in the arc to produce products including gaseous products;
• means causing the products of the thermal treatment to pass beneath the surface of the smelt;
• and
• means for removing the gaseous products of the thermal treatment from said receptacle after passing through the smelt.