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Publication numberUS2653905 A
Publication typeGrant
Publication dateSep 29, 1953
Filing dateNov 22, 1948
Priority dateDec 6, 1947
Publication numberUS 2653905 A, US 2653905A, US-A-2653905, US2653905 A, US2653905A
InventorsAannerud Sigurd Arthur
Original AssigneePyror Ltd
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
Process for total treatment of copper-containing iron pyrites
US 2653905 A
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Description  (OCR text may contain errors)

p 29, 1953 s. A. AANNERUD 2,653,905

PROCESS FOR TOTAL TREATMENT OF COPPER-CONTAINING IRON PYRITES Filed Nov. 22, 1948 Pyrite 1 (Fe 52 m.)

Fe Setc. Hz 804 Sludge Fe 504 '(Fe,Cu,S+ Ouartz etc.)

Slag (Fe 0,8i 02) INVENTOR SIGURD ARTHUR AANNERUD TouJZ/rm'm. 5i Tuubmixv ATTORNEYS Patented Sept. 29, 1953 PROCESS FOR TOTAL TREATMENT OF COPPER-CONTAINING IRON PYRITES Sigurd Arthur Aannerud, Thamshavn, Norway,

assignor, by. memo assignments, to Pyror Limited, Pembroke, Bermuda, a corporation of Bermuda Application November 22, 1948; Serial No. 61,376

According to several methods heretofore known of treating copper-containing iron pyrites, the sulphur content of the ore is recovered as elementary sulphur and the copper content in the form of copper or copper matte. To this end, the recovery of elementary sulphur is effected by the use of reducing agents such as coke or, if desired, carbon monoxide for the reduction of S02 produced by total or partial roasting of the pyrites. Apart from the fact that thereby a large quantity of fuel is consumed, the iron content of the ore and other metals which in addition to the copper may be present in small quantities, are often not utilized. In addition, when roasting with air, the S02 gas is not obtained in pure form, but mixed with the constituents of the air, for which reason an absorption of S02 from the roast gases is often effected before the reduction process. 7

It is an object of the present invention to provide a process whereby the sulphur content of the ore may be recovered as elementary sulphur by the use of reactions known per se without requiring coke or other reducing agents for the main reaction. It is another object of this invention to provide a method as set forth in the preceding paragraph, which will make it possible to utilize substantially the whole mineral content of the ore to obtain pure sulphur-containing gases.

These and other objects and advantages of the invention will appear more clearly from the following description in connection with the accompanying drawing, which shows a flow sheet for the course of the process according to the invention.

The iron pyrites are first heated in preferably continuously charged, closed furnaces indicated by the reference numeral l, to a temperature whereby one sulphur atom is driven off. The heating may take place in countercurrent to a suitable heating medium either indirectly by means of muffles or the like, or directly with an inert circulating gas. However, care is taken that the ore does not attain a temperature of about 1009 centigrades at which the sintering begins, and preferably the operation takes place with a maximum temperature up to 900- centigrades.

The escaping sulphur may be condensed in the usual manner by cooling in steam boilers (indicated at 2 in the drawing), thereby utilizing the condensation heat,

Owing to the driving 01? of the first sulphur atom without sintering, the ore thus treated, which now contains FeS and sulphides of copper and of other metals which may be present,

Norway Decemberfi, 1947 '4 Claims. (01.204-112).

and quartz, is now in an entirely porous, solid form, which makes it particularly suitedfor a treatment with chemicals- In this form it is supplied to containers 3 in which it is treated with sulphuric acid which may be used in a low concentration down to about 5%. By this treatment the major part of the iron is dissolved, while a corresponding proportion of sulphur is driven off as sulphurated hydrogen. This process can be carried out at usual temperature, but in order that it shall proceed more rapidly, it is convenient to keep a somewhat higher temperature of for example 90 centigrades, utilizing part of the heat content of the ore from the first step of treatment. It has been found that the dissolution can be carried on in a fractional manner, that is, that it is possible to dissolve most of the iron without dissolving the copper, which remains in the solid residue.

The iron sulphate formed is, supplied to electrolysers 4 equipped with a suitable diaphragm for the electrolytic separation of the iron, if detreatment may for example take place by means of the Claus-process (catalytic combustion HzS-eO I-I2O+S), but a procedure is preferred in which a minor part of the sulphurated hydrogen gas is burntso as to form soziindicated by 5), using preferably oxygen from the elec trolysis as indicated above (if the combustion is efiected with air, the sulphur dioxide may in known manner be absorbed in a suitable absorbing agent and driven off again as -percentual) whereafter the remaining sulphurated hydrogen gas is mixed with the sulphur dioxide in the volume ratio 2:1 and passed over a suitable catalyser (at 6) whereby the following reaction is obtained at a suitable temperature Flor this process it is possible for example to use porous alumina-containing catalyser mass in known manner, Since by this process it is possible to obtain the sulphur in liquid form and H20 in the form of steam, the sulphur may without difficulty be collected separately. And as the process may take place together with a reduction of the gas volume, it may be accelerated by the application of pressure. Thus, additionally,

3 the H20 formed is obtained in the form of pressure steam which can be utilized for example for driving pressure pumps for the gas to be introduced.

In the residue from the acid treatment the copper remains together with the silica and some iron and sulphur apart from valuable metals which may be contained in the ore, such as gold, silver and cobalt. This rich copper sludge may be treated by known methods for recovering the copper and other valuable constituents for example by direct melting and Bessemer treatment or roasting and extraction, if desired combined with a flotation. As shown in the drawing, in which this treatment is indicated by 1, it is possible also for this roasting to use pure oxygen from the electrolysis and to have the remainder of the sulphur recovered by mixing the sulphur dioxide formed by the roasting, with the gas from the combustion of HzS, which is conveyed to the catalyzing step. The measuring of oxygen and sulphurated hydrogen to the various steps of the process will in that case be made by means of gasometres in such a manner that the correct mixing ratio 2:1 is obtained for the catalysis.

I claim:

1. A process of treating an iron ore comprising sulphur and containing valuable metal constituents including copper, which includes the steps of (a) heating the ore under non-oxidizing conditions to a temperature below sintering temperatures of the ore so as to decompose said ore and produce gaseous sulphur, leaving a porous calcined product with substantially all of the original FeSz present reduced to FeS, (b) dissolving the major part of the iron content of said calcined product selectively by leaching fractional portions of said calcined product with dilute sulphuric acid solution, leaving undissolved the major part of the copper and other of said valuable metal constituents present forming a resultant mixture comprising ferrous sulphate solution, gaseous hydrogen sulphide, and a sludge containing undissolved solid matter, and (c) electrolyzing said ferrous sulphate solution in a diaphragm electrolytic cell to electrolytically recover metallic iron and sulphuric acid and gaseous oxygen, (d) subjecting said sludge to a roasting treatment with oxygen recovered by step (c) to produce gaseous sulphur dioxide and effect recovery of said valuable metal constituents, and (e) reacting said sulphur dioxide with gaseous hydrogen sulphide from said mixture in the presence of a catalyst for forming liquid sulphur and steam.

2. A process of treating an iron ore comprising sulphur and containing valuable metals including copper, which includes the steps of (a) heating the ore under non-oxidizing conditions to a temperature below that at which said ore sinters but high enough to decompose the ore and produce gaseous sulphur, leaving a porous calcined product with the original FeSz substantially reduced to FeS, (b) dissolving the major part of the iron content of said calcined product selectively by leaching fractional portions of said calcined product with dilute sulphuric acid solution leaving undissolved the major part of the copper and other of said valuable metal components present forming a resultant mixture comprising ferrous sulphate solution, gaseous hydrogen sulphide, and a sludge containing undissolved solid matter, (c) electrolyzing said ferrous sulphate solution in a diaphragm electrolytic cell for electrolytically separating and obtaining sulphuric acid, metallic iron and gaseous oxygen, and (d) subjecting said sludge to a roasting treatment with the oxygen thus obtained to recover said valuable metal constituents from said roasted sludge.

3. A process of treating an iron ore comprising sulphur and containing valuable metals including copper, which comprises the steps of heating the ore under non-oxidizing conditions to a temperature .below that at which said ore sinters but high enough to produce gaseous sulphur while leaving a porous calcined product with the original FeSz substantially reduced to FeS; dissolving the major part of the iron content of said calcined product selectively by leaching said product in fractional portions with dilute sulphuric acid solution, leaving undissolved the major part of the copper and other of said valuable metal components present producing ferrous sulphate solution, gaseous hydrogen sulphide, and a sludge containing undissolved solid matter; electrolyzing said ferrous sulphate solution in a diaphragm electrolytic cell for obtaining sulphuric acid, metallic iron and gaseous oxygen; reacting a part of said gaseous hydrogen sulphide with said oxygen thus recovered to produce sulphur dioxide; and reacting said sulphur dioxide with further amounts of said hydrogen sulphide in the presence of a catalyst for forming liquid sulphur and steam.

4. A process for treating an iron ore comprising sulphur and containing valuable metals including copper, which comprises the steps of heating the ore under non-oxidizing conditions to a temperature below that at which said ore sinters but high enough to decompose said ore and produce gaseous sulphur and leaving a porous calcined product containing the original Fess substantially all reduced to FcS; dissolving the major part of the iron content of said calcine selectively by leaching fractional portions of said calcine with dilute sulphuric acid solution leaving undissolved the major part of the copper and other of said valuable components present to produce a resultant mixture comprising ferrous sulphate solution, gaseous hydrogen sulphide, and a sludge containing undissolved solid matter; electrolyzing said ferrous sulphate solution in a diaphragm electrolytic cell for recovering sulphuric acid, metallic iron and gaseous oxygen; burning a part of said gaseous hydrogen sulphide with a part of said oxygen; subjecting said sludge to a roasting treatment with a portion of said oxygen, for recovering said valuable metal constituents therefrom; and reacting sulphur dioxide, formed by said burning and by said roasting, with another portion of said gaseous hydrogen sulphide in the presence of a catalyst and in controlled proportions so as to produce liquid sulphur and steam.

SIGURD ARTHUR AAN N ERUD.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 748,662 Sebillot Jan. 5, 1904 814,049 Johnson Mar. 6, 1906 984,703 Ramage Feb. 2l, 1911 1,083,250 Hall Dec. 30, 1913 1,378,145 Stuclt May 17, 1921 1,565,353 Estelle Dec. 15, 1925 1,602,795 Greenawalt Oct. 12, 1926 1,633,091 Greenawalt June 21, 1927 1,654,930 Greenawalt Jan. 3, 1928

Patent Citations
Cited PatentFiling datePublication dateApplicantTitle
US748662 *Nov 1, 1901Jan 5, 1904 Beibl sebillot
US814049 *May 27, 1903Mar 6, 1906Woolsey Mca JohnsonMethod of treating matte.
US984703 *Jul 14, 1910Feb 21, 1911Nat Tube CoProcess of making sulfuric acid and electrolytic iron.
US1083250 *Jun 25, 1913Dec 30, 1913William A HallProcess of recovering sulfur.
US1378145 *Aug 14, 1917May 17, 1921Edward Studt FranzElectrolytic deposition of copper from acid solutions
US1565353 *Jun 15, 1925Dec 15, 1925Konstantin Estelle Axel TeodorTreatment of iron sulphide ores containing other metals
US1602795 *Jan 31, 1925Oct 12, 1926 Metallfbg-ical pbocess
US1633091 *Sep 7, 1926Jun 21, 1927William E GreenawaltMetallurgical process
US1654930 *Aug 13, 1926Jan 3, 1928William E GreenawaltCopper-extraction process
Referenced by
Citing PatentFiling datePublication dateApplicantTitle
US2868635 *Dec 27, 1956Jan 13, 1959Pyror LtdMethod of treating iron sulfide-containing ore or concentrates
US3864223 *Mar 21, 1973Feb 4, 1975Continental Can CoMethod of Regeneration spent Iron Electroplating Solutions with Concomitant Desulfurization of Coal
US3964901 *Oct 19, 1973Jun 22, 1976Sherritt Gordon Mines LimitedMultistage
US4064022 *Dec 1, 1975Dec 20, 1977Motoo KawasakiMethod of recovering metals from sludges
US20110089045 *Apr 14, 2009Apr 21, 2011Francois CardarelliElectrochemical process for the recovery of metallic iron and sulfuric acid values from iron-rich sulfate wastes, mining residues and pickling liquors
Classifications
U.S. Classification205/554, 205/633, 205/593
International ClassificationC22B15/00, C01B17/06
Cooperative ClassificationC01B17/06, C22B15/0056, C22B15/0006
European ClassificationC01B17/06, C22B15/00B2B, C22B15/00H6