UNITED STATES PATENT OFFICE.

ERNST HEILIGENDORFER, OF CANELAS, MEXICO. BARREL AMALG AMATON OF PRECO US METALS.

SPECIFICATION forming part of Letters Patent No. 651,506, dated June 12, 1900. Application filed July 16, 1897, Serial No. 644,832, (No specimens.) To all, whom it may concern: amalgamation. The chemicals, copper, quick Beit known that I,ERNSTHEILIGENDORFER, silver, salt, and bluestone which are used in a citizen of Germany, residing at Canelas, barrel amalgamation can, however, form no Durango, Mexico, have invented an Improve copper amalgam. The amalgamation Work 50 ment in Barrel Amalgamation of Precious is therefore less energetic than in raw pan Metals; and I hereby declare the following to amalgamation and the quicksilver is not pro be a full, clear, and exact description of the tected against sulfur. All raw ores contain S80. ing an excess of sulfur Would destroy the My invention relates to an improvement in quicksilver and must be excluded from bar'- 55 amalgamation of precious-metal-bearing ores rel amalgamation, though such base ores may by what is known as the “barrel’ process; contain silver, as silver sulfid, and Would be and it consists, essentially, in the employ ranged as free-milling ores were they not over ment of copper amalgam in conjunction with loaded with sulfur. My remedy, then, will What are known as “rebellious’ ores when be to introduce copper amalgam into the bar treated by this process. For such ores as can rel, and by this simple device barrel amal be desilverized without roasting the processes gamation is enabled not only to desilverize of raw pan amalgamation and raw barrel free-milling ores more perfectly, but to ex amalgamation are to be preferred. Both tend its capacity over a wider range of raw processes, however, are but partially success ores which up to this time have been consid ful for the so-called “free-milling silver ered rebellious for raw pan amalgamation as combinations with sulfur, antimony, and ar well as for raw barrel amalgamation. All Senic. equal success is obtained in the raw barrel RaW pan amalgamation works principally amalgamation of gold-bearing sulfurets which by the action of copper amalgam formed from have been treated by a roasting process. 25 quicksilver and precipitated blue-stone, (sul When rebellious ores are to be amalgam fate of copper.) Copper amalgam is more ated by the barrel process, they must first be active in the work of amalgamation than pure roasted with or without salt, after which they quicksilver and metallic copper. At the same can be worked by the addition of copper time When sulfur attacks copper amalgam it amalgam with perfect Success. 75 Will sulfurize only the copper without dam Having thus described my invention, what aging the quicksilver, and this protection of I claim as new, and desire to secure by Letters the quicksilver by copper amalgam is far Patent, is more efficient than metallic copper in contact The improvement in the process of amal With quicksilver can afford; but while pan gamating silver and gold ores in vessels of 35 amalgamation is thus secured against serious Such material as will not decompose copper losses of quicksilver a great deficiency in this sulfate, consisting of the combination of me form of treatment is that there is no chlorina tallic copper, quicksilver, salt, blue-stone and tion, because iron decomposes at once the cop copper amalgam, substantially as herein de per and cuprous chlorid, and for this reason scribed. several of the silver combinations remain in In witness whereof I have hereunto set my the pan in the so-called “rebellious’ condi hand. tion. On the other hand, raw amalgamation in Wooden tubs and barrels or in stone ves ERNST HEIILIGENDORFER. sels is aided by chlorination with copper and Witnesses: 45 cuprous chlorid and will desilverize several LIBRADO SILVA, silver combinations which resist raw pan MANUEL OSORIO.