716 



GEOLOGY AND MINING INDUSTRY OF LEADVILLE. 



Analysis XXXV. Roasted chamber ddst ■ 

 Bafional. 



Portion soluble in water. 



Oxychloride of lead 



Osybromide of lead 



Oxy iodide of lead 



Sulpbate of zinc 



Sulphate of manganese 



Sulpbate of lime 



Sulpbate of magnesia 



Caustic magnesia 



Chloride of potassium 



Bromide of potassium 



Iodide of potassium 



Chloride of sodium 



Hygroscopic water 



Total .- 



Portion soluble in acids. 



Oxide of lead 



Phosphate of lead 



Sulphate of lead 



Sulphide of lead 



Chloride of lead 



Bromide of lead 



Iodide of lead 



Oxide of antimony 



Oxide of tin 



Oxide of copper 



Oxide of zinc 



Sulphate of lime 



Caustic magnesia 



Titanic acid 



Oxide of bismuth 



Chloride of silver 



1. 105970 

 I. 023270 

 I. 001620 

 I. 01 0000 

 I. 036100 

 I. 447440 

 I. 049050 

 .013650 

 . 083080 

 I. 032870 

 '. 001370 

 1. 13C460 

 . 225000 



. 826460 

 '. 443000 

 t. 676220 

 1. 105760 

 I. 236140 

 I. 009230 

 1. 117000 

 I. 004300 

 1. 144800 

 ,. 810000 

 ,. 224000 

 I. 447200 

 I. 037800 

 i. 0573C0 

 1. 122640 



Portion soluble in acids— Continued 



Bromide of silver 



Iodide of silver 



Oxide of cadmium 



Gold 



Araenioua acid 



Peroxide of iron 



Oxide of manganese {MnaOj) 



Alumina 



Carbonate of lime 



Seleniona and tellurona acids 



Oxides of indium, thallium, new metal 



Total 



Portion insoluble in acids. 



Silica (combined) 



Silica (quartz) 



Oxide of lead 



Araenious acid. 



Oxide of antimony 



Oxide of tin 



Titanic acid 



Peroxide of iron 



Alumina 



Lime 



M.agncsia 



Oxide of zinc , 



Oxide of magnesia 



Potash 



Soda 



Carbon (from charcoal and coke) 



Graphite 



Total 



0. 032270 

 0. 002390 

 0. 005500 

 0. '000200 

 0. 277000 

 12. 020000 



0. 746000 



1. 044000 

 Trace 



Traces 



Traces 



85.481290 



8. 332000 

 1. 500000 

 0. 690000 

 0. 000200 

 0. 000300 

 0. 000100 

 0. 018000 

 0. 687000 

 0. 100400 

 0. 072C00 

 0. 035000 

 0. 026000 

 Trace 

 0. 025000 



0. 015000 



1. 505000 

 0. 290000 



13. 296000 



Discussion. — Everything indicates that the dnst was roasted at a very high tem- 

 perature, and this is proved beyond doubt by the fact that traces only of carbonic 

 acid are detected. 



On comparing this analysis with the average analysis (XXXIV) of unroasted 

 chamber-dust, it is found that the percentage of lead is considerably increased, i)ut 

 that a considerable quantity of silver is lost. One notices also that the quantity of 

 chlorine, bromine, and iodine is about haif what it was in the average sanjple of dust. 

 Coupling this with the loss of silver, it may justly be inferred that silver is lost in the state 

 of chloro-bromo-iodide, and that some lead is also lost in the same form. The quantity 

 of phosphate of lead has also diminished instead of increasing, showing that lead is 

 also lost in this form. The percentage of arsenic and antimony is lower than in the 

 unroasted dust, but this appears to be the only advantage gained by roasting, and a 

 very slight one it is in these cases. Sulphur, instead of being driven off by roasting, 

 is concentrated in the form of sulphate of lead, amounting to 37 per cent., and repre- 

 senting 5 per cent, of sulphur instead of 2 per cent., as in the chamber dust. Lastly, 

 about 9 per cent, of carbon is driven off at great expense. This carbon is so intimately 

 mixed with the original dust that by simple heating in the blast furnace there would 

 be more than enough of it to reduce all the lead of the fumes. In fact, everything in- 



