| 摘要 |
<p>957,724. Separating coal particles. SOC. DE PRODUITS CHIMIQUES D'AUBY. Aug. 11, 1960 [Aug. 11, 1959], No. 27820/60. Heading B2H. Coal particles are separated from "deads" or schists by flocculating in an aqueous medium moist particles derived from a previous washing operation, if desired with an addition of particles emanating from a dust removal step preceding the washing operation, filtering the flocculated particles and subjecting them to flotation, the flocculation and flotation steps being effected in the presence of a single surface-active agent which comprises (a) one or more polyalkylene polyamines of the formula: (where R denotes a saturated or unsaturated straight- or branched-chain hydrocarbon group with 8 to 22 carbon atoms, n is from 2 to 8 and p is from 2 to 6), and (b) an oily mixture of aromatic hydrocarbons corresponding in composition to the dephenolated coal tar fraction of boiling points ranging from that of naphthalene to that of anthracene ; preferably R corresponds to the acyl groups of acids existing as glycerides in natural oils and fats or fractions of such acids. The surface-active agent may additionally be employed as a separating adjuvant during water extraction of "fines" collected after the initial washing, as adjuvants in filtration or flocculation of schists and "extra-fines", and/or as a coating agent during the production of briquettes from"extrafines". The process is illustrated by Fig. 1 which shows a circuit installation with a coal crushing and screening unit 1 with a duct 2 for the discharge of dust, washing units 3-for the "fines"-and 6-for the coarser particles-each with ducts 5 and 7 respectively for the discharge of washing water into a flocculation and filtration unit 11 ; a duct 12 enables moist dust to be also discharged into unit 11 if desired. The washed "fines" (grain size less than 10 mm.) lead to a water extractor unit 8, e.g. a centrifugal hydroextractor, to be freed from water prior to passing to a separator unit 22, which sorts the "fines" into the coarsest elements (2 to 10 mm.), for discharge via duct 24 to a coking installation or steam boiler furnace, and the "extra fines" (less than 2 mm.) for discharge to a briquetting unit 21. The flocculated sludge from unit 11 passes to a flotation unit 15 from which "extra-fines" and schists are discharged into filtration units 18 and 19 respectively. The filtered "extra-fines" are passed to the briquetting unit 21 whilst the filtered schists are fed to a separator unit 26 which separates the finest (less than 0.5 mm.) from the coarsest, the liquid effluents from the filtration units passing back to the washing units 3 and 6. A reservoir 30 containing the single surfaceactive agent as above is provided to supply both the flocculation and filtration unit 11 (duct 31) and the flotation unit 15 (duct 32) and if necessary other units (ducts 33 to 36) as shown. Specifications 953,550 and 957,723 are referred to.</p> |
