744 GEOLOGY AND MINING INDUSTRY OF LEADVILLE. 



Zone of agglomeration 1,095 C. 



"Weight of charge entering zone 397, 0293 



It loses : 



One-eleventh of the total loss in dust and fumes 0.529! 



One-third of the COz from carbonates 5.8020 



(Of this j is reduced in upper zones, while J escapes.) 



Oxygen from T ' FeO reduced toFe 1.9249 



(This forms with CO 5.2935 pounds COj, of which | is reduced above, while 



j escapes.) 

 C oxidized by $ COi expelled from carbonates in zone 1,200 C. (0.8289 pounds 



COi) 0.2261 



C oxidized by -f, COj formed in zone l,i-00 C. (32.1256 pounds COi) 8.7616 



17. 2439 



Total C oxidized in zone 1,095C 8.9877 



Total CO formed in same zone 41.9426 



Of this latter there is used for redaction of oro 3. 3686 



Leaving for escaping CO 3R 5740 



Zone of combustion and reaction by contact of solid matter, 1,200 C. 



Weight of charge entering zone 379.7854 



It loses: 



One-eleventh of the total loss in dust and fumes 0. 5293 



One-third of the COi from carbonates 5.8020 



(Of this $ is reduced in upper zones, while i escapes.) 



C oxidized to COj 32. 1JJ7 



38. 4580 



Remaining in furnace 341. 3274 a 



Weight of bullion reaching zone of crucible 61.6170 



Weight of slag produced 281.6520 



343.2690 



Chemical reactions of the different zones Soaie important reactioilS begin to take 

 place in zone 570 C. and are continued in zone 075 C. Oxide of lead acts on galena, 

 sulphide of silver, aud pyrites, and some sulphurous add is evolved. Mattes begin 

 to form. Oxide of lead acts on silica, and some .silicate of lead is formed. In practice 

 dolomites lose here a portion of their carbonic acid, but the discussion has been carried 

 on as if dolomite behaved like carbonate of liuie, in order to get at extreme results. 



In zone 780 C., the important reaction of reduction of lead taking place, several 

 more reactions are produced in consequence. Metallic lead acts on arseniate and 

 antimouiate of lead, forming arseniuret and antiiuoniuret of lead, with regeneration 

 of oxide of lead. Metallic lead acts also on sulphate of lead, with regeneration of oxide 

 and evolution of sulphurous acid; all the reactions which have escaped completion in 

 the upper zones are completed here. Metallic lead acts on galena, and subsulphides 

 are formed. Sulphide of lead acts on sulphate and oxide of lead, with evolution of 

 sulphurous acid and reduction of lead. Sulphide of lead acts ou silicate of lead, aud 

 mattes are produced. Metallic lead acts ou chloro-bromo iodide of silver and forms 



aThe discrepancy between this number and that next below, representing the sum of bullion and slag, is mainly <!;K- to 

 the fact that while Mr. Guyard expressly says (p. 739) he has neglected consideration of speiss and matte in this iliscussion, 

 he nevertheless allows for the reduction of , FeO in zone 1,093 C. Calculations carried out with a view to correcting the 

 above discrepancy give 32.7272 as the amount of carbon burnt in zone 1,200. Such correction involves, naturally, slight alter- 

 ations in some of the figuies, representing loss in all except the four highest of the other zones, and also alters the data 

 relative to the amount of blast theoretically required. A second cause of difference between the above numbers is found 

 in the fact that the figures for composition of charge (p. 74P) are accurate in some cases only to the second decimal figure. 

 The slight inaccuracies in the values of the third decimal necessarily involve errore in calculations carried to four decimal 

 places. (S. F.E.) 



