SEPARATING GOLD FROM ARGENTIC CHLORIDE. 



Oa" an improved metliod of separating the Grold from the Argentic 

 CKloride produced in Gold-refining by Chlorine Gras. 



\_Read iefore the JRoyal Society of New South Wales, 20th November, 1872, 

 by Adoiph Leibitjs, Esq., Ph. D., Senior Assayer of the Sydney Branch 

 of the Royal Mint.'] 



In refining argentiferous gold by means of chloriae gas (Mil- 

 ler's patent) the silver is eliminated in the form of chloride of 

 silver, or as now termed, argentic chloride. 



In the paper read by Mr. Miller before this Society, on 

 December 1st, 1869, he described this process so fully that 1 need 

 not refer to more of it than that part which speaks of the argentic 

 chloride produced. This argentic chloride is never pure, but 

 contains, besides chloride of copper, a considerable quantity of 

 gold, stated by Miller, in the paper quoted above, as 2 per cent, of 

 the gold previously refined. If this auriferous argentic chloride 

 is reduced to metallic state without freeing it of its gold, silver 

 bullion results, containing from 12 to 20 per cent, of gold, the 

 average being about 18 per cent. This gold exists chiefly in com- 

 bination with chlorine, and also as a double compound of chloride 

 of gold and silver. By melting the chlorides in a boraxed clay pot, 

 with from 8 to 10 per cent, of metallic silver, the greatest part 

 of this gold was removed, but never the whole. Miller states 

 that with proper care the amount of gold remaining in the silver 

 need not exceed 3 parts in 10,000. "While such was the case 

 in many instances during the time the experiments were going 

 on, the amount of gold left in the silver bullion produced varied 

 from 3 to 27 parts in 10,000, the average being 13 parts in 

 10,000. Lengthy experience obtained since, has shown that, 

 when working on a large scale, and therefore with less time at 

 disposal than when engaged in experimental trials only, the 

 results became still more variable, the gold in the silver bullion 

 having been not seldom as much as 100 to 150 parts in 10,000, 

 and often 10 to 40 parts in 10,000. This irregularity in the 

 results obtained made it desirable to institute further experiments 

 with a view of arriving at a method which would if possible take 

 out all the gold, or at all events would only leave a minute and 

 regular proportion of this metal in the silver bullion produced. 

 To free the silver bullion from gold by dissolving it in acid would, 



