Show TREATMENT OF MIXED i. i L. L SULPHIDE ORES AT ATt ATI I t THE UNIVERSITY of the most pressing problems in inthe inthe i I the treatment of mixed sulphide ores ors is the removal of iron sulphides from zinc I sulphide concentrates es The ThE department of metallurgical research of the University University sity of Utah which is co conducted ducted through I I operation co-operation with the United States bur bureau bureau bu bu- bu- bu r reau co of ot mines wil has baa seemingly worked out I tue method for removing this Iron py- py I rite tle The Thus method consists of ol treatment I of Ji the mixed sulphides In a reducing at- at tie at about degrees C. C The I pyrite e loses one e atom o of sulphur r u under ig these ec c conditions mi mie a and Is r reduced d ht to a au form which will wi react with dilute diute sulphuric J acid while the zinc sulphide Is resistant to cd the acid In this way the iron can be removed making a marl marketable zinc I product In man many marty Western ores the presence of large amounts amount of iron ion Inthe in inthe 1 tl the zinc concentrate has been a curse to 1 the Ue milling industry because when iron I Iwas was above 10 30 0 per cent the concentrate might contain as much as a 30 worth orth o of I zinc to ever every ton toil and yet be I Ii The e success c of the e method depends upon P i tho use of rS cheap s sulphuric cd acid but at atthe atthe I Ithe the same time cle cles clee the large lage smelting Interests Inter Inter- ests eats are at a loss to know what to do with their sulphur fume from the smeltIng smelt smelt- inter inter-I hug Ing wih In furnaces The conversion of this sulphur ul hur into into sulphuric acid is quite cheaply cheap cheap- ly done clone but lt heretofore the trouble has l been een that there th-re th was wa an insufficient market market market mar mar- ket for the tile acid acla This process of removing log ing iron from the zino concentrate should prove to be an important consumer of ofa a acid id and Is only one Illustration of how t one Ol branch braadh h of or the thc bureaus bureau's work worl may fitin fit fitIn ft In with another as as one section of th the bureau has been studying smelter fume problems while up to the present time the Salt Lake station staton has been d devoted voted entirely Sal to the metallurgy of zinc arid and ad lead One of the other operative co-operative co fellowships fellowships fellow fellow- ships In the department of metallurgical research of the University of Utah and under the direction of the bureau of ot mines Is now studying the question queston of the use s of sulphur dioxide from smelter roaster roaster and other fumes in the removal removal of zinc and copper copper from rom complex mixtures mixtures mixtures mix mix- tures containing zinc lead copper and iron After the removal of the zinc a residue containing copper lead and iron can nn be treated in a lead copper smelter while the lead-copper lead smelter never pays for the zinc and usually penalizes the presence of ot more than 7 pe per cent of the I IThe zinc The idea o of forming a soluble of the zinc by the application of solutions l of sulphur dioxide to an ore Is not new 01 But tr the trouble r b dh has b been that thata a number of engineering difficulties have arisen se in applying the process r ce Tile The present present pres pres- fn ent work is taking up a study of each r h difficulty and the methods of turning It into an advantage It I is believed that the bureau has carried this process nearer near near- er to successful completion than any other institution which has taken talen it up up I and it would now no look as though most of the difficulties encountered can be disposed of f |