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.

Abstract: Sewage sludge from municipal and industrial sewage systems can be incinerated in conjunction with the incineration of refuse in a refuse incinerator as environmentally safely as possible, with a favorable energy balance and low expenditures for technology and equipment. The sewage sludge can be fed into a rotary tubular kiln, while in a countercurrent, flue gas from a refuse incinerator can be passed through the rotary tubular kiln. The resulting vapors from the sewage sludge incineration can then be injected back into the refuse incinerator for afterburning, while the components of the vapors are useful for the reduction of the formation of nitrogen oxide during the incineration of the refuse.

Abstract: A combustion furnace particularly for refuse incineration comprises furnace walls which enclose a fire chamber having a grate extending across at least a part of the fire chamber of the furnace. The furnace walls have a portion adjacent the grate which comprises inner and outer spaced metal walls with a hollow space between said walls. A metal shield plate is spaced inwardly from said inner furnace wall and extends around at least a substantial portion of the periphery of the grate which is adjacent the furnace walls and there is an intermediate hollow space between the shield plate and the inner furnace wall. The inner metal furnace wall has openings communicating with the hollow space between the inner and the outer furnace walls and the shield plate has openings communicating with the intermediate hollow space between the shield plate and the inner furnace wall with the fire chamber.

Abstract: A combustion furnace particularly for burning refuse comprises a furnace housing having an inlet adjacent one end and a discharge chute at the opposite end. A grate extends between the inlet for the material to be burned and the discharge and it slopes downwardly toward the discharge but it includes step portions each of which has a grate part which slopes in a direction opposite to the overall sloping of the grate. The overall slope of the grate is about 10.degree. to 20.degree. from the horizontal while the sloping of the individual stepped portions is from between 5.degree. and 10.degree..