Abstract: A process for incinerating waste material to produce slag without the addition of fuel other than the waste material begins with carbonizing the waste material in a low temperature process in a generator to produce carbonized solid material with a high energy content and flammable gases which are extracted from the waste material. The carbonization and temperature in the generator are controlled by limiting the supply of air to the material in the generator, the temperature being less than 1000° C. The carbonized waste material and the carbonization gases are delivered together to a furnace which is supplied with excess air. The carbonized material and carbonization gases are incinerated at a high temperature, typically 1400° C., in the furnace, thereby substantially completely incinerating burnable products in the furnace and melting materials which will not burn. The result is a glassy slag which binds therein materials such as heavy metals which could otherwise be pollutants.