Arizona citizen., 1875-12-11
From s. F. Post, November 24. ] REDUCING ORES.
The New MIudeIeR PrOcess-Public Experiments with Copper Ores An Interesting Exhibition.

peOple interested III tne TeuuCllOn Ol metals from their ores, gathered at the corner of Main and Harrison streets at noon today to witness some experiments with the new Mindeleff process. The owners of the process are Demitory Mindeleff and T. H. Alexander, and these gentlemen have in view the or ganization of company to work the process on this coast The experiments were conducted on copper ores. The theory of the process is based on the fact that hydrogen unites powerfully with oxygen and sulphur in statu mas cente, and that gaseous carbon possesses even greater power to eliminate these and their impurities. Pure hydrogen has long been known as a good reduc- ing power, but its cost of production is so great that it cannot be used on an extensive scale For this expensive agent, Professor Mindelef substitutes light carbureted hydrogen, which he claims to be more valuable reducing agent than simple hydrogen, at equal cost of production for each, the carbon of the former more than neutralizing the interference of its accidental com. ponents other than hydrogen and car bon.
 In the case of ores carrying sulphur, the hydrogen will take some portion of thIs metaloid and produce sulphur. eted hydrogen, while the carbon will escape with the rest ID its clutch aS bisulphide of carbon. Professor Min deleff applies his discovery in an ap paratus consisting essentially of but two parts, viz: A retort is kept at a red heat for reducing the ore, and decOm posing chamber for converting coal gas into light carbureted hydrogen by depositing the excess of carbon, which would otherwise coat the ore, and in terfere with its reduction. The ordin ary Illuminating gas passes from tho street mains and through the decom poser to the mass of heated ore in tht report; while the various waste gases such as sulphurous acid, surphureteC hydrogen, carbonic acid and watel vapor escape through 8 suitably ar ranged pipe, together with the vapor. of any metals or metaloids whicl volatilize at or below the temperature of the retort. In this way all impuri ties which render an ore "rebellious under usual methods of treatment, arC either completely eliminated, or so fal reduced in quantity and modified a. regards their combination as to be readi 1 ly handled by the final processes O smelling and refining. The proces. pivots upon any oxidized condition O. the ores. It contemplates ores which either are naturally oxidized or have been artifcially subjected to an oxldiz ing roasting. Its action is therefore claimed to be perfect upon any class C. original ores. The old way consider. all ores as sulphides, the new as oxides Starting, then, from the datum that tn, naturally oxidiZed ores are truly typi cal of all the objects to which the Min deleff process is applied, the decision in that case is claimed to be cOnclusiv, as regards all others.
 The experiments today were con 0ucted by placing a charge of car bonate of copper in the retort, anC bringing it to a fair red heat. The gas was then admitted under pressur equal to that afforded by column O water four inches high-the seal of tn escape pipe being so set as to permit tn slow efflux of the waste gases. Tn ore was introduced cold, and as | gradually approached the desired heal the flow of steam and sulphurous acit from the escape pipe was copious. A least the steam ceased, showing tha the ore was sufficiently dried; am after waiting a half hour to insure tn heating of the entire mass of tn charge, the flow of gas was turned on the flow of steam then recommencet with greater vIgOr than before, bu this time it had its source in the chem ical union of the hydrogen of the ga with the oxygen it was stripping iron the ore. This was conclusive evidenc that deoxidatiOn was progressing Simultaneously with this surrender O oxygen, sulphureted hydrogen and tn vapor of bisulphide of carbon wer given of, and st later period, as tn steam fell off in quantity, the volum of the two latter foul gases increased and the carbonic oxide flame aoded 1t weight to this evidence. At the end o about an hour and half the character istic yellow of the original coal ga began to show at the test burner ol the escape pipe, and the completion o tue treatment was indicated at the en' of two hours, by the flame burning free, with the brilliant yellow of UT contaminated coal gas. The ore was
 tolerably firm carbonate when intro duced, carrying about thirty-two pc cent of copper. When withdrawn, tn charge appeared as loosely compacte' Jumps of gangue, showing on the SUI face and to the very heart of each threads and globules of absolute metal with particles so finely divided as |