Chemistry of inorganic compounds – Sulfur or compound thereof – Oxygen containing
Reexamination Certificate
2005-03-01
2005-03-01
Silverman, Stanley S. (Department: 1754)
Chemistry of inorganic compounds
Sulfur or compound thereof
Oxygen containing
C210S726000, C423S356000, C423S592100
Reexamination Certificate
active
06861041
ABSTRACT:
A method for treating and upgrading effluents containing at least a metallic sulphate comprising adding at least a base to the effluent to precipitate the metallic ions in the form of iron oxy-hydroxides Fe(OHx) wherein x=2 and/or 3; separating the precipitated hydroxide calcium sulphate CaSO4; and separating the calcium sulphate CaSO4precipitated during the preceding step. Said method enables obtainment of calcium sulphate (white gypsum) substantially free of metals and therefore capable of being upgraded and iron oxy-hydroxides likewise capable of being upgraded.
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Derwent Abstract Accession No. 1976-09794X, “Spent pickle liquor disposal—treated with acids, pptd. iron salts reacted with metal salts” (corresponding to JP 50009575—Jan. 31, 1975).*
Derwent Abstract Accession No. 1977-20817Y, “High purity gypsum mfr.—by adding a calcium waste liq. contg. sulphuric acid and iron” (corresponding to JP 52017391—Feb. 9, 1977).*
Derwent Abstract Accession No. 1977-82557Y, “Sulphuric acid pickling solutions regeneration—using ammonium chloride and then milk of lime and ammonia” (corresponding to SU 536255—Mar. 12, 1977).*
Derwent Abstract Accession No. 1983-763869, “Magnetite and calcium sulphate from etching residue—by treatment with ammonia to ppte. magnetite and then with milk of lime to ppte. calcium sulphite [sic]” (corresponding to SU 973484—Nov. 15, 1982).*
Derwent Abstract Accession No. 1985-039440, “Processing waste sulphuric acid—for recovery of acid and useful gypsum by-product” (corresponding to EP 132820—Feb. 13, 1985).*
Derwent Abstract Accession No. 1986-011018, “Ferric oxide prodn. for ferrite—by adding ammonia source to ferrous salt aq. soln. in inert gas atmos., adjusting pH, oxidising and heating” (corresponding to JP 60235726—Nov. 22, 1985).*
Derwent Abstract Accession No. 1991-097661, “Producing high purity ferrous sulphate soln. from acidic waste soln.—by diluting with water, neutralising with e.g. ammonia to form pptes. which are removed, . . . ” (corresponding to JP 03040924—Feb. 21, 1991).*
English translation of SU 536 255, published Nov. 25, 1976.*
English translation of SU 973 484, published Jun. 17, 1977.
Hyvrard Francois
Muller Pascal
Hertzog Ardith E
Sarp Industries
Silverman Stanley S.
Westman Champlin & Kelly P.A.
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