Bisbee daily review., 1904-04-29
PROF. J. DOUGLAS MAKES ENTERTAIN ING ADDRESS TO SENIOR CLASS OF MICHIGAN SCHOOL
 OF MINES

VI
 Half a century ago every blast furnace
 in the Black Country of England, and
 in our own then insignificant iron cen ters, was a torch. belching forth the
 flame and the smoke and gas which are now in the hot stoves used to heat
 the blast and raise the steam for the
 blowing engines, thus reducing the consumption of carbon in extracting
 pig iron from its ores to about one
 quarter of what formerly was con sumed.
 "It was later still before MT. Besse-
 mer succeeded practically in applying
 the heat generated by the combustion of the carbon and silicon in the pig iron to the conversion of cast iron into steel It only remains to apply the
 waste heat from the converter to the generation of power for operating the
 blowing engine to make the cycle com plete.
 Pyritic Smeiting.
 Another example of the utilization of the fuel !n an ore from the separar ton of its valuable constituents is afforded by the treatment of pyrities.
 Pyritic smelling can hardly be said to
 have passed beyond the stage of in cipient development. Yesterday hot
 blast was declared necessary, Today cold blast at high pressure is found more advantageous, but such progress is being made by many metallurgists the world over, to place pyritic smelt- ing on a sound technical footing, that before long we should see not only the sulphur in sulphuratic ores used
 to smelt the charge, but the sulphur escaping from the stack and the cop per converter recovered as acic by the contact of some other process.
 But a still more instructive ex- ample of the saving, not only of mon ey. but of the valuable constituents of pyrites, has been worked out in Spain.
 Till within a few years the min erals from the great lenses of pyrites
 of Rio Tinto and Tharsis were sorted and portions richest in copper ship
 ped to the chemical centers or the
 world The poorer ore was roasted in l heaps for the purpose Of sulphatizing 1artially, and extracting as much of
 he copper by teaching as possible. | Only Partial Recovery of Elements. The pyrites exported are treated by ! he so-called Henderson process, which
 however, should be more justly credit ed to Longmaid After kiln roasting he crude ore, in order to extract most
 of the sulphur for acid making, the
 cinders are crushed and roasted with salt, whereby the copper is almost con- pletely chloridized, and rendered
 soluble in the weak hydrochloric acid | liquor obtained by passing the leach liquors through a condensing tower
 connected with the roasting furnace. 1 Iron is used as the precipitant of ne copper, but before the cupriferous | liquors pass to the copper precipitat- | ing tanks the silver and some of the gold which have been dissolved with
 the copper are separated by iodide of
 zinc, as first proposed by Claudet- The tank of residIes, practically free from
 sulphur and copper. consists of ve-y
 aure iron oxide which was formerly used as fettling in the pudding fur mace, but now enters the blast furnace.
 Thus the sulphur, the copper and the
 precious metals and the iron are all
 more or less perfectly recovered.
 And we have here, therefore, and instance of an attempt to save all the
 useful elements of the ore. But till , the fuel used in roasting can be elim- nated and till the salt consumed in chloridizing and the iron in precipitat ing are regeneratet, or recovered ir @Ln .f nvS : erations, looked at from an economical point of view is incomplete.
 Legislation Forces Research.
 The treatment, however. of the
 second class ores at the mine is whai wish particularly to call your at , .ention to, as 1t conveys several les sons.
 The manufacturing chemists O. Europe were driven to the use of py , rites about half a century ago by thu
 unwise action of the Sicilian govern ment in imposing a heavy export dut, . lon birthstone. Three notable produc , CTS of pyrites soon entered the marke . 1.-the Mason Barry mines of Portugal , and the Tharsis and Rio Tinto on thu odknC CE1tA VI oCPOoAto Ah eAS
 of Huelya, Spain.
 The Portugese government forbad' . the roasting of pyrites by the Mason , Barry company. which, therefore, wa I forced to screen and export all iti - lump ore IL was soon discovered tha decomposition set up in the piles O . raw fine screenings, when they wer' - wetted, resulting in the extraction O - the copper.
 r The fact, however, was overlooked las of any importance by the two grea' , neighbors of the Portugese company I They were building their second cias' e ore into huge heaps and roasting of g the sulphur at enormous loss to them : selves and the destruction of all sur s rounding vegetation. The Tharsis com
 lpany was the first to correct it's mis
 take, but though the Tharsis and Ri'
 Tinto properties are only Q few mile' e apart, it was years before the RI s Tinto was willing to abandon its ol' F obsolete extravagant methods. !, The result Is now. that both a