USRE8859E - Improvement in chlorinating ores - Google Patents

Description

structed that when charged with 'ore,

' UNITED STATES PATENT OFFICE.

J HOWELL MEARS OF PHILADELPHIA, PENNSYLVANIA.

IMPROVEMENT m CHLOIRINATING ORES.

To altwhom it may concern:

"nating Ores, which improvement is fully set fdrth in thefollowing specification.

My invention consists in treating ores by j means of chlorine gas underpre'ssure, or under pressure greater than that of the atmosphere.

'Incarrying out my invention, I proceed as follows: The ore is properly roasted and pul- V verized, (the finer the better,) and introducedinto a tank with about one-half its weight of water, into which is slaked a proper proportion of lime, (ordina'rylime of commerce,) the whole then being thoroughly incorporated by, rotating the tank. Chlorine gas is now introduced into the mass, and the tank kept in motion until no more gas will be absorbed, which can be determined by a suitable device for the purpose. The rotation of the tank is then discontinned, dilute sulphuric acid is added ,to the mixture, and the tank is again rotated for from half an' hour toone hour, when the chlorination is complete. I

There is now a large excess. of chlorine underpressure, produced by the chlorine gas bemg evolved by the sulphuric acid from the lime, sulphate of lime being formed and chlorine thrown off. The tank is now tapped, and the excess of chlorine is conducted into a second tank or vessel, similar to .the first tank or vessel, and also containing a charge of ore ready to he treated.

After the efl'ervescence has ceased, and almost all of the gas has passed 011 into the second tank, hot water is introduced into the first tank until the temperature of the mass reaches about 160 or 200, when all of the free chlorine will have been expelled. The tank is now turned, opened, and emptied into a proper vessel, when the water containing the chloride of gold in solution is drawn ofi; and the metal precipitated with sulphate ofiron or other precipitant.

The tank ,or vessel that I employ is so con- I 8m. it will be'about two-thirds full, and or sutllcint Specification formin'gpart of-Letters Patent No. 193,381, dated September 18, 1877; Reissue 8,859, dated August 19, 1879; application'filed January 31, 1879.

strength to endure a pressure of forty to-fifty pounds to the square inch.

The shaft on which-the tank revolves will be hollow, so'that the chlorine gas may be admitted into the tank while the latter is'in motion. The inner face of the tank will be provided with cleats, secured thereto at intervals, so as to facilitate the stirring or agitation of the mass, and with an apartment or receptacle for sulphuric acid loca d near the top or vent of the tank, whereby w on the latter is turned it will empty. the contents of the apartment or receptacle into the mass of ore.

By this methodof subjecting ore to chlorine .in connection with lime, I am enabled to charge the' ore with, a very large volume of chlorine,

which is condensed by absorption by the lime, and held in store, as it were, until the proper time, when it is again evolved under circumv tances most suitable for combining with the gold.

By the evolution of chlorine gas within the mass of ore while in a state of agitation in such quantities and under circumstances to produce pressure, the combination of the gold and chlorine takes place with almost as much am .tivity as it does in nitro-muriatic acid. 7 3 By having the chlorine gas in large excess, and under the pressure produced, gold will be taken up of acoarser grade than ordinarily, and

fine gold is instantly combined. The process is complete in from one tot'wo hours, thus saw-.2

'ing from seven to eight hours in introducing chlorine into the-ore and'also the time allowed for the gas to remain in the ore from twenty-four I to forty-eight hours before chlorination is said to be complete by the'usual processes ofehlorination." In from one to three hours all coarse gold will becombined that is not dissolved by the ordinary processes of chlorination. I am aware that it is not new to mix pulverized ore with common salt and subject them to the'pressure of steam.

I am also aware that it is not new to treat refractory ores of silver by boiling them in a solution of common salt and hydrochloric acid in the presence of free chlorine gas; and I am 1 furthermore aware that it is not" new to dissolve the gold in the forniof-chloride by treating the ore with hypochlorite of lime and hydrochloric acid, then removing the excess of chlorine by steam, and precipitating the gold by sulphurous acid; wherefore I disclaim such features.

Having thus fully described my invention,

I hereby disclaim all the well-known proeesses,

chemical and mechanical, which enterinto said description; but

What I do claim, and desire to secure by Letters Patent, is-- I In treating ores, the process of chlorination, consisting in subjecting the ore, mixed with water, in a strong alr-tight vessel, whilein a state of agitation, to chlorine gas under a greater pressure than that of the atmospheric pressure, by generating chlorine gas in said vessel. or tank by chemical means, so as to produce the pressure for the purpose of extracting the precious metals, in combination,

as chlorides in solution, substantially as and for thepurpose set forth.

o J. H. MEARSQ Witnesses:

Enwn. W. WILSON,

HARRY Mums.