Patents Assigned to Engitec S.p.A.
  • Patent number: 5750019
    Abstract: A hydrometallurgic and electrochemical process for processing sulfur antimony ores and residues is disclosed, the end products from which are electrolytic antimony and elemental sulfur. The concentrate of sulfur antimony ore, leached with a solution of caustic alkali according to the known techniques dissolves, as sulfur salts as much Sb as possible, whilst the other heavy and precious metals which accompany the antimony bearing ore remain unchanged in the residue. From the solution of antimony sulfur salts pure Sb.sub.2 S.sub.3 is precipitated by acidification and this sulfide, separated from the solution by filtration, is leached with a ferric fluoborate based electrolyte which oxidizes sulfide into elemental sulfur and dissolves antimony as Sb.sup.3+ fluoborate.
    Type: Grant
    Filed: May 5, 1997
    Date of Patent: May 12, 1998
    Assignee: Engitec S.p.A.
    Inventor: Marco Olper
  • Patent number: 5618507
    Abstract: A wet process of regenerative type for removing SO.sub.2 contained in combustion gases in which SO.sub.2 is caused to be absorbed by a diluted aqueous solution of BaS, with a mixed precipitate of elemental S, BaSO.sub.3 and BaSO.sub.4 being formed by the consequent reactions. Sulfur is extracted from the precipitate--recovered by filtration--by using a solution of (NH.sub.4).sub.2 S; the resulting polysulfide is distilled, with pure elemental S and the solution of (NH.sub.4).sub.2 S to be recycled, being obtained. The residual mixture of BaSO.sub.3 and BaSO.sub.4 remaining after sulfur extraction is reduced with coal in a high temperature furnace, in order to obtain BaS to be recycled, as an aqueous solution, to the SO.sub.2 absorption step.
    Type: Grant
    Filed: February 21, 1996
    Date of Patent: April 8, 1997
    Assignee: Engitec S.p.A.
    Inventors: Marco Olper, Massimo Maccagni