Abstract: A method for incinerating excess sludge from biological waste water treatment plants, in particular sludges arising from the manufacture of paper or paper pulp, preferably using the magnesium fusion process. Before incineration, the excess sludge is neutralized with the same base as used in the paper pulp process and the dust entrained by the combustion gas is precipitated to recover the base.

Abstract: A process and plant for drying and then separating moist salts, such as magnesium sulfite, in which the moist magnesium sulfite is heated to a temperature greater than or equal to about 200.degree. C. in a dryer and the passed through a solid materials lock into a separating plant. The dryer is heated by a circulating stream of exhaust vapors which is heated in a heat exchanger by exhaust gas generated in the separating plant so that the water of crystallization of the magnesium sulfite as well as residual humidity is eliminated during the drying process. Vapor-free acid anhydride, usually sulphur dioxide, is prepared in the separating plant from the dehydrated salt and a metal oxide, e.g., MgO, is recovered or otherwise used. The acid anhydride may be liquified and has a large degree of purity.

Abstract: A rotating tube heat treatment installation, for example a rotating tubular kiln for the thermal splitting of MgSO.sub.3, or a slag cooler for the separation of salts and aluminum, comprises as the main replaceable component, a rotating tube (1) which is surrounded by a tubular jacket (2) and separated therefrom by a gap. The tubular jacket (2) is linked to the rotating tube (1) by means of a carrier system, and has drive (8) and possible bearing races and bandings (9) mounted externally. The connections (3, 4) for the heat exchange fluid are disposed at its ends, and thermal insulation, in particular light insulation (7), is fitted internally. In this way the rotating tube, which is exposed to corrosion and thermal stresses, is simplified structurally and can be readily replaced.

Abstract: A dry process for desulfurization of a power plant flue gas recovers, e.g. from an electrostatic precipitator, the solids which include unreacted absorbent, absorption reaction product and fly ash, and recycles at least part of this recovered solid product to contact with the flue gas for further absorption.

Abstract: A method of and an apparatus for the desulfurization of the flue gases from a fossil fuel power plant. A particulate absorbent is contacted with the flue gases in a dry desulfurization step, particulates being then separated from the flue gas and being utilized in part as a secondary absorbent in a subsequent scrubbing of the flue gas. The sludge from the wet scrubbing is combined with the remainder of the dried particles from the separator to form a settable composition.

Abstract: An absorbent for the dry removal of sulfur dioxide and other noxious and toxic components from a combustion flue gas which consists essentially of at least one finely divided alkaline-earth compound and an additive selected from the group which consists of at least one carboxylic acid or an alkali metal, alkaline-earth metal or ammonium salt thereof.

Abstract: An absorbent for the dry removal of sulfur dioxide and other noxious and toxic components from a combustion flue gas which consists essentially of at least one finely divided alkaline-earth compound and an additive selected from the group which consists of at least one carboxylic acid or an alkali metal, alkaline-earth metal or ammonium salt thereof.

Abstract: In a mosaic printing head for applying lettering by means of needles which are ejected as the head is passed over a sheet of paper, the needles are accommodated in a tubular column of bearing metal. Near one end, the tube is formed with a transverse wall containing a circular arrangement of guide holes for the needles, each guide hole being slightly inclined towards the tube axis. The operative ends of the needles are arranged in a row and parallel to one another with the aid of an orifice member provided for the tube.