354 



PROCEEDINGS OF SECTION B. 



when the " blister copper " is subsequently electrolytically refined. 

 With few exceptions, the antimony has been an impurity coming from 

 gold ores containing it ; but in some cases it has been present in the 

 fahl ores containing silver which were from time to time smelted. I 

 can give, however, no results on the elimination during calcining of 

 antimony from these fahl ores by themselves, as by the time they arrived 

 on the scene antimony was well established as one of our enemies, and 

 had to a large extent been vanquished. 



The following is a result of calcining a mixture of copper ore and 

 gold ore containing antimony and arsenic so that the percentage of 

 these in relation to the amount of copper present could be ascertained 

 as a guide for the subsequent smelting operations. The copper ore 

 consisted chiefly of copper pwites, and the antimony and arsenic as 

 sulphide concentrates, the furnace used being a revolving calciner of 

 the Oxland and Hocking type. 



Copper . . . 

 Sulphur . 

 Arsenic . 



Antimony 



5-62 



18-23 



4-56 



5-69 



Calcined Ore. 



7-13 



5-87 



1-56 



For CTery 100 parts of Copper. 



Raw Ore. Calcined Ore. 



324 



81 



101 



82 

 3-5 



22 



On melting such a mixture of calcined ore the slag produced 

 always carried a fair amount of antimony ; but, also, the copper 

 contained in such a slag was high, probably due to the copper being 

 present in the slag to a large extent in combination with antimony. 



The furnace used for smelting was a reverberatory, which gives a 

 better elimination of antimony than is obtained by the use of a blast 

 furnace, due to the reducing conditions present in the latter. 



Once the antimony is in combination with the copper, or present 

 in a regulus or matte containing copper, its eUmination is very im- 

 perfect. Calcining a regulus containing antimony only ehminates a 

 comparatively small percentag >, as the following result will show : — 



Copper . . . 

 Antimony 



Raw Regulus. 



Calcined 

 Regulus. 



Per every 100 parts of Copper. 



Raw Regulus. 



Per cent, 

 41-7 



0-76 



Per cent. 

 42-9 



0-52 



1-82 



Calcined 

 Regulus. 



1-21 



