Patent GB-362343-A (GB)
Title: Improvements in or relating to the treatment of materials containing iron and other values
IPC: C22B1/08
Filed: 1930-05-30
Abstract: Ores or other materials containing iron with or without other metals such as nickel, copper, cobalt, zinc, or lead are treated with a gaseous mixture of a chlorinating agent and an inert diluent gas to form chlorides of the metals present, and to volatilize the non-ferrous chlorides and at least a substantial part of the ferrous chloride.  The chlorides are condensed and the ferrous chloride oxidized to form iron oxide with generation of dilute chlorinating gases for further use.  Oxide ores are first treated to reduce iron and other metals (except chromium and gangue constituents) to the metallic state.  In the case of sulphide ores, sulphur is also recovered from the exit gases. Nickel and cobalt may, if desired, be recovered with the iron as oxide.  The non-ferrous metal chlorides may be freed from iron, either by forming and volatilizing ferric chloride, or by oxidizing the ferrous chloride to form ferric chloride and oxide and then leaching the residual mixture of chlorides and ferric oxide.  As shown in Fig. 1, a Cuban iron ore, after reduction, is fed through a furnace A for treatment with the chlorinating agent at say 800-850 DEG  C., whereby all the chlorides formed are volatilized and the residual gangue contains only chromium oxide, which may be recovered by mechanical means.  Alternatively if the unreduced ore is mixed with carbonaceous <PICT:0362343/III/1> <PICT:0362343/III/2> material and then chlorinated chromium chloride is also formed and volatilized.  The chlorides, optionally after passage through a dust catcher B are condensed in C, and the residual gases pass through a fume catcher D and thence through a collector E packed it may be with adsorbent carbon to remove arsenic, antimony, or bismuth chlorides, the inert gases resulting being returned to A for further use.  Any excess of such gases is bye-passed through a collector F to waste.  Metallic chlorides from C, D are transferred to a furnace G and treated at say 300-400 DEG  C. with a mixture of chlorine and inert gases from an oxidizer H to form and volatilize ferric chloride, which is passed to H and there burnt with air, with or without carbon monoxide, for instance as described in Specification 314,075, [Class 1 (iii), Oxides &c., Metallic]. Non-ferrous chlorides are obtained from G and ferric oxide from H, whilst the mixed chlorine and inert gases from H are passed in part to G and in part to A for chlorination purposes. Some of the ferric chloride from G may be passed direct to A.  In modifications where the furnace H is dispensed with, the mixture of chlorides in G may be treated with air at 280-350 DEG  C. to volatilize ferric chloride all of which is returned to A, and to give as residue the non-ferrous chlorides mixed with ferric oxide, or at say 400-500 DEG  C. with countercurrent, or at 850-900 DEG  C. with co-current working, to give ferric chloride or chlorine for return to A, and a residue of iron, nickel, and cobalt oxides.  In the application to sulphide ores, Fig. 3, the ore is treated in furnace A with inert gas and either chlorine, ferric chloride, or sulphur chloride at 850-950 DEG C. to volatilize substantially all the chlorides formed together with liberated sulphur, chlorides are condensed in C, D, (with omission of D if desired) impure sulphur containing chlorides in I1, I2 and pure sulphur in I3, I4. The impure sulphur is passed to J to meet a stream of chlorine and nitrogen from H, and sulphur chloride formed is passed to A, whilst metal chlorides left are passed with the main body of chlorides to G and treated in G, H as described in Fig. 1. The exit gases from I4 are also treated in collectors E, F as previously described.  In a modification, the furnace A which may then be a shaft furnace may be so operated say at 800 DEG  C. that a part only of the ferrous chloride is volatilized, the remainder passing out with the gangue, and in such case C, D may be omitted, and all the metallic chlorides be condensed in I1, I2.  In J ferrous chloride is then preferably converted to and volatilized as ferric chloride, leaving a residue of non-ferrous chlorides only for recovery, the gangue and ferrous chloride from A being treated for instance in G.  In a second modification the furnace H is dispensed with as before, ferric chloride from G being fed directly to A, and the generator J for sulphur chloride is also omitted, all metal chlorides from C, D being passed to G, and all the sulphur being recovered pure.  In a third modification, operating A so that some ferrous chloride is removed with the gangue and the mixture passed to G, and dispensing as before with the generator J and furnace H a second furnace G is used to oxidize the volatilized metallic chlorides.  In treating oxide ores sulphur in some form may be added to enable the fume catcher D to be omitted and the metallic chlorides passing through C to be collected by such added sulphur, which is returned to the cycle through J.  Metalloid chlorides, for instance, bismuth chloride, may be used in like manner to sulphur. Specification 306,691, [Class 1 (iii), Oxides &c., Metallic], also is referred to.