Arizona republican., 1915-06-13
6be MINES of ARIZONA

ing high grade ore. have not been
 conducive to experiments involving
 any radical change in the treatment of ores. The present high grade
 of ores. The present high price of
 the metal due to its use in making
 explosives, has stimulated the in
 dustry to an extent not seen m
 years.
 Practically all foreign competition
 has been shut off and American pro
 ducers are getting almost any price they demand.
 At present two methods are in use to obtain mercury from it's ores on large scale. One depends on the fact that at d high temDerature
 the oxygen of the air combines with
 the sulphur of the mercuric sulphide, forming sulphur dioscide and metallic mercury The other depends upon heating the mercuric sulphide with iron or lime. the sulphur combining with the iron or lime. setting the mercury free. The first method is earned out in shaft furnaces, usually of the continuous type. and is the
 more Important of the two commer- cially. The second method is ap- piled in the retorts and is too eX- pensive 9 procedure except for ricA
 ores
 In spite of it's universal applica-
 ton the furnace method has dis
 advantages that will never be over
 come These are high cost of in
 stallation. quantity of soot caught
 with the mercury in the condensers.
 imperfect confederation. low eXtrac-
 tion. particularly on low-grade ores.
 poisoning of worNmen, excessive
 amount of mercury tied up in con
 densers and the time required to
 place mercury OF the market after
 the plant is put into operation.
 The cost Of building and continu-
 ous furnace of the type most used
 in California is approximately 5000 per ton of capacity. This figure would
 be excessive in some cases and low
 in others. but represents the aver age cost. On low grade ores 0.5 per cent or lower. the soot caught with the mercury in the condensers usu- ally necessitates retorting the pro duct. The brick work of the con dens-rs absorhs mercury and furnaces have been known to run from eight months to one year before any clean up could be made. The actual invest ment in furnace plant would not only be the installation cost of S1009 per ton of capacity. but would i'm clude operating costs until mercury cou,i be placed on the market.
 To those considering the installa- ton of furnace plant. to take ad- vantage of the present high prices, the time required to put the mer- cury on the market is of especial importance. Thes.. disadvantages led l C. A. Munholland to experiment with ! a hope of devising a wet process for | the extraction of mercury. particu- | Iarlv from low grade ores. It has ] long been known that rqercuric sul- phiGs is soluble in alkaline sUlphides | containing free alkaline hydrate. and | BeecneI, in his monograph "Geology | of thc quicksilver Deposits of the1 Pacific Coast" made elaborate eX- periments to prove that the Cali | fornia deposits were due to the Gis- solving and subsequent precipitation l of cinnabar from such solutions The | scheme of. treatment suggested fE | deduced from his eX- periments. was to grind the ore in i an alkaline sulpnlde solution, were lev the cinnabar was dissolved. sep arating the solution from the ore ny filtration or deoantation. pTecipitat ing the mercury out of solution with ! zinc hvdrate. which brought down a mixture of zinc sulphide and mel curic sulphide. Gissolving the zinc sulphide out of the precipitate with sulDauric acid. and retorting the re- | maining precipita te of mercuric sul-