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US 4,226,617 AGranted
Method for treating a mineral sulfide
AssigneeNichols Engineering Societe Anonyme
InventorJacques J. M. J. A. G. Dupont
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AssigneeNichols Engineering Societe Anonyme
InventorJacques J. M. J. A. G. Dupont
Estimating the term…
This invention relates to method and apparatus for treating a sulfur containing material having at least one principal sulfide either in the form of a sulfide or in a form that is transformable into a sulfide and at least one auxiliary sulfide more volatile than the principal sulfide or transformable into another sulfide more volatile than the principal sulfide, wherein the sulfurous material is heated in one furnace zone, having a non-oxidizing atmosphere in the gas phase, to a temperature between that required for volatilization of the principal sulfide and that required for volatilization of the auxiliary sulfide to volatilize the auxiliary sulfide and labile sulfur, without volatilizing or substantially oxidizing the principal sulfide; and heating the sulfurous material in another furnace zone, having an oxidizing atmosphere in the gas phase, to a temperature lower than that required for substantial oxidization of the principal sulfide, to oxidize the volatilized labile sulfur and auxiliary sulfide, without substantially oxidixing the principal sulfide.
A process for treating a sulfur containing material having at least one principal sulfide and at least one auxiliary sulfide including arsenic sulfide more volatile than the principal sulfide, said process comprising the steps of passing said material downwardly through a first furnace zone having an oxidizing atmosphere in the gas phase, said first zone being maintained at a temperature less than about 425.degree. C. to prevent substantial oxidation of the principal sulfide but sufficient to oxidize volatilized auxiliary sulfide and labile sulfur, passing said material from said first furnace zone downwardly into a second furnace zone having a non-oxidizing atmosphere in the gas phase, heating said material in said second furnace zone to a temperature between about 400.degree. C. and 1000.degree. C., lowering the sulfur content of said material by volatilizing the auxiliary sulfide and any labile sulfur in said second furnace zone without volatilizing or substantially oxidizing the principal sulfide, passing the volatilized auxiliary sulfide and labile sulfur formed in said second furnace zone through said first furnace zone in countercurrent flow to that of said material in order to oxidize same and, as a result, heat said material as it passes through said first furnace zone and withdrawing the principal sulfide from said second furnace zone.
A process for treating a pyrite ore including therein essentially FeS.sub.2 and arsenic sulfide or mispickel which is transformable into arsenic sulfide that is more volatile than FeS, said process comprising the steps of passing said pyrite ore downwardly through a first furnace zone and thence through a second furnace zone, heating said pyrite ore in said second furnace zone having a non-oxidizing atmosphere in the gas phase to a temperature between about 400.degree. C. and about 1000.degree. C. sufficient to thermally decompose FeS.sub.2 to FeS and to diminish the sulfur content by volatilizing the arsenic sulfide and the labile sulfur without volatilizing the iron sulfide and without substantially oxidizing the iron sulfide, passing said volatilized products from said second zone upwardly to said first zone, and heating said pyrite ore in said first zone having an oxidizing atmosphere in the gas phase to a temperature lower than about 425.degree. C. to oxidize the volatilized sulfur and arsenic sulfide, without substantially oxidizing the downwardly moving iron sulfide.
A process for treating a pyrite ore including therein essentially FeS.sub.2, As.sub.2 S.sub.3, CuFeS.sub.2 and ZnS, said process comprising the steps of, progressively passing said pyrite ore from top to base of a multiple hearth furnace by rabbling from hearth to hearth, while maintaining a lower zone of said furnace in a non-oxidizing atmosphere in the gas phase at a temperature between about 400.degree. C., and about 1000.degree. C. sufficient to thermally decompose FeS.sub.2 to FeS and to lower the sulfur content by volatilizing to produce S, As.sub.2 S.sub.2, and As.sub.2 S.sub.3 without volatilizing the iron sulfide and without any substantial iron oxide formation, passing said volatilized products upwardly into an upper zone of said furnace in countercurrent flow to said pyrite ore, while maintaining said upper zone in an oxidizing atmosphere in the gas phase at a temperature lower than about 425.degree. C. to oxidize said volatilized products to form S0.sub.2 and As.sub.2 0.sub.3 without substantially oxidizing the iron sulfide, and withdrawing from the top of the upper zone said S0.sub.2, As.sub.2 O.sub.3 and sublimed material and withdrawing from the bottom of the lower zone the remainder of the material including essentially FeS, Cu.sub.2 S and ZnS.
Dependencies are inferred from the claim text.