1887.] 



Contributions to the Metallurgy of Bismuth. 



173 



Having observed, in conducting experiments with bisnrath and its 

 sulphides, that sulphide of bismuth becomes very easily impregnated 

 with copper, I made the simple experiment of fusing the cupreous 

 bismuth with bismuth sulphide, and found it possible by this means 

 to remove every trace of copper, the sulphur readily combining with 

 the metallic copper. 



In this absorption a proportion of bismuth is reduced equivalent 

 to the amount of copper taken up in the operation. 



The residual bismuth and copper sulphides thus produced amount 

 to but a small proportion in comparison with the quantity of alloy 

 treated, and the bismuth is readily recovered by subsequent reduction 

 and refusion. 



Large quantities of alloy can be treated at one operation, and 

 the bismuth so freed from copper is available for commercial 

 purposes. I have found it better, when bismuth is associated with 

 other metals, such as arsenic, antimony, lead, tellurium, &c, as well 

 as with copper, to separate all these metals (see former papers) 

 before attempting to remove the copper by the foregoing method. 



The operation has been conducted successfully upon many 

 thousands of pounds of similar alloy, and the following figures will 

 show the results obtained in one case, as an example : — 



Weight of cupreous bismuth treated == 314 lbs. containing O'lO per 



cent, of copper, equal to approximately 0*3 lb. 



From the operation described I obtained of bismuth lbs. 



free from copper 282 



Of bismuth subsequently reduced and refined from the 



skimmings 29'9 



And bismuth left in residues for further treatment with 



larger quantities (by determination) 2 



3139 

 lb. 



Copper from the skimmings 2 



Copper left in residues 0"1 



0-3 lb. 



Thus the whole of the copper and of the bismuth, within a small 

 fraction, is accounted for, the latter being obtained as commercially 

 pure bismuth and. wholly free from, copper. 



As the above operation shows, the first separation frees 90 per cent, 

 of the bismuth at once from the copper associated with it. 



It may be as well to state that I have effected complete separation 

 with bismuth containing proportions of copper varying from one- 

 tenth of 1 per cent, to 1 per cent, by the above process. 



