Arizona republican., 1915-05-02

| manufacture is about 300 miles, more or less. according to the route from 1 the mine. Wedge also undertook a
 study of sulphating and chloridizing l roasts. His requirements were that ! the ore be crushed to pass d F nm.
 screen He showed that if the sul- 1 phide ore could be mined in parallel with the oxidized ore, and in propor- i tion to their respective tonnages, there would be sufficient sulphur for 1 his purpose and that a very high extraction could be obtained He also showed that sufficient advantages could be had in using salt to offset it's cost and the difficulties that might arise later. Wedge also show ed that small amount of heavy sulphides from the Bfsbee mines
 crushed and mixed with the oxide
 ore would give very high per centage of extraction after the mix
 ture had been subjected to sul-
 phatiEg roast. He also. introduced
 the idea that a preliminary water
 leach would give a perfectly pure
 sulphate solution from which the cop
 per could be recovered electrolytically
 and that the acid thus regenerated
 would be sufficient to complete the
 leach.
 Frederick L-aist in the meantime
 was conducting a number of eXperi-
 ments governing processes in like
 way, and among these was the de-
 velopment 'ot an oXidizing roast on
 Anaconda tailings. Like Wedge he
 found that by calcining sulphides or
 mixed sulphides and oxidized ores
 high percentage of the copper could
 be extracted by teaching. Tempera-
 ture control was vastly important,
 a. the developments of both Wedge
 and Lais showed If too high a tenn
 perature is used large amount of
 the copper becomes insoluble in the strongest acid, but in both cases tenn perature control was demonstrated to be simple and practicable, and under these circumstances practically no in soluble copper compounds were form ed. In Laist's case, however, the use of salt is essential on account of the silver contents of the charge, | but he finds that it is not necessary 10 use this in a chloridizing roast and that a solution of salt with sul- l phuric acid gives him the desired l extraction on the product from the l Cxidizing roast.
 The manufacture of sulphuric acid | by the chamber process. while simple. | requires very large investment, and : in this case the transportation charges would amount to more than the cost of the acid. The chamber and the contact processes, of course. are the two important manufacturing pro- Cesses, but even a casual study of wet methods of copper recovery shows that there are other methods Of acid manufacture involving a prin- -iple similar to the chamber method, hat might be used in parallel with 1 -he recovery of the copper from solution with less investment for plant and with a saving in energy hat is important.
 The Kay process includes a sul- 3hating or an Oxidizing roast, as he hooses. to get sulphide of copper nto soluble form. and he adopts ne same process for this purpose IS followed by Wedge and Laist.
 The Slater process and the Midland process deserve study. They depend ipon the use of complex series of nlorides and hypochlorous com ounds that will dissolve many salts f copper that sulphuric acid will lot todch. They will attack. among ther things chalcocite, and they de- ierve serious consideration in many important but special cases. as they |