1887.] Contributions to the Metallurgy of Bismuth. 



89 



February 10, 1887. 



Professor STOKES, D.C.L., President, in the Chair. 



The Presents received were laid on the table, and thanks ordered 

 for them. 



The following Papers were read : — 



I. " Contributions to the Metallurgy of Bismuth." By Edward 

 Matthey, F.S.A., F.C.S., Assoc. Roy. Sch. Mines. Commu- 

 nicated by John Percy, M.D., F.R.S., Pres. Iron and Steel 

 Inst. Received August 18, 1886. 



§ 1. Bismuth : its Separation from Gold, and its Refining Action 

 upon same during the Process of Separation. — In bringing the above 

 subject under notice, it is necessary to allude to some of the facts dis- 

 tinguishing this very interesting metal. 



Bismuth, in some of its important characteristics and reactions, 

 resembles lead. And one of the chief points of resemblance between 

 these metals is their ready oxidation, and their absorption by bone- 

 ashes or wood-ashes whilst so oxydised. I refer of course, to the 

 process of cupellation. 



This ancient and serviceable process, still employed universally 

 for the separation of gold and silver from lead, is equally applicable 

 to bismuth, if associated with these precious metals ; and, like lead, 

 bismuth may be readily employed as a vehicle or means of collecting 

 gold and silver from their ores in reduction processes ; but its com- 

 parative cost accounts for its non-employment in this respect. 



Commercially speaking, bismuth differs from lead in its greater 

 value, lead being worth at present £13 to £14 per ton,* whilst bismuth 

 realises between £700 and £800 per ton ; this high value being due to 

 its greater rarity and to its limited and special uses. 



As is well known, bismuth ores are frequently auriferous ; and 

 one of the points which it is my desire to bring under notice is the 

 effectual separation of the gold from bismuth by a rapid and effica- 

 cious process. 



Of course, nothing could be easier than to separate these two 

 metals by the ordinary process of cupellation. The gold, by these 



* June, 1886. 



