Abstract: A process for the production of a black iron oxide pigment from Fe2O3 hematite iron oxide which may be an impure oxide produced by the “Ruthner” process or by other means, or which may be a mineral hematite. The process may be used to upgrade poor quality synthetic or natural hematite, or to improve their performance as red pigments, by conversion to black pigment with subsequent oxidation of the magnetite so produced back to hematite. The process uses a low temperature aqueous slurry reaction in which the hematite is contacted with a soluble source of Fe(II) ions in the presence of a soluble source of Fe(III) ions in an aqueous alkaline medium to convert the same to Fe3O4.

Abstract: Granular active carbon having satisfactory adsorbency and hardness characteristics and having a high proportion of its porosity in the below 2000 A range is produced from granules prepared from coal fluid energy milled until not more than 1% of the particles have diameters above 38 microns. The coal has a low ash and high carbon content and may have a British Standard Swelling number from 2 to 7 although it is preferred for the volatile matter content of the coal to be not more than 40% on a dry ash free basis. The granules may be produced by compacting milled particles having a temperature of from 50.degree. C to 250.degree. C between unheated pressure rolls.