Abstract: Desublimator for isolating sublimation products from reaction gases, which consists of a closed housing and a plurality of rows of finned tubes accommodated horizontally and superposedly therein, successive superposed finned tubes being supported, and mutually spaced, with limited adjustability, by means of cage-like perforated sliding shoes surrounding them in a box-like manner, the sliding shoes of the individual finned tubes being directly stacked one above the other and resting loosely on common supporting girders anchored to the housing, and the supporting girders having, in cross-section, the outline of a triangle with its apex pointing downward.

Abstract: A method and apparatus for making an antimony trioxide powder having a specific particle size distribution from crude antimony trioxide which contains a small amount of impurities having a higher vaporization temperature by passing the crude antimony trioxide through a plasma arc tail gas reaction zone, vaporizing in a chamber communicating with the reaction zone the antimony trioxide at a temperature that liquifies the impurities, exiting the gases from the chamber through one port, draining the liquified impurities from the chamber through the port, contacting the exiting materials with a quench gas, mechanically clearing the exit port of solidified impurities and separating the antimony trioxide powder from the other exiting materials.

Abstract: A plasma method and apparatus produce oxide particles having average diameters determined by adjustment of process conditions. Feed material is fed into a dual chamber reaction zone in which a plasma environment is established to cause the feed material to be vaporized. Subsequently, effluent containing the vaporized feed from the reaction zone is passed into a quenching zone where it is subjected to a quenching medium, the volume, velocity and direction of which are adjustable to determine output particle size characteristics. Feed material may be an oxide per se or one which forms an oxide in situ through reduction and/or oxidation.

Abstract: Phthalic anhydride is recovered from gases in a multiple heat-pipe exchanger system, one or more for condensing phthalic anhydride from gases containing vapors thereof and one or more simultaneously melting out the condensed phthalic anhydride solids, the exchangers being switched in alternate cycles to melt out from the surfaces of the exchanger tube ends on which the phthalic anhydride solids were first accumulated, and to condense phthalic anhydride solids in the exchanger or exchangers from which the phthalic anhydride was cleared by melting out.