PECULIAE ACCRETIONS. 



731 



Peculiar accretion found at Gage, Hagaman & Co.'s smelter Tbis acCTC'tiou wa^ a thiu 



compact, yelljwisli-green mass of altcruate layers of sulpliide of lead aud yellowisb- 

 greeu oxides ; it coutaiued ouly a very few grains of lead iu floe particles. Tbis 

 accretion is remarkable ou account of tbe enormous quantity of zinc concentrated iu it 

 (53 per cent.), cbiefly iu tbe state of oxide (G5.o per cent.). It is also tbe ouly accre- 

 tion iu wbicb were found traces of cbloriue, bromine, aud iodine. Tbe rational report 

 of tbe analysis has been arranged so as to sbow as clearly as possible bow tbe differ- 

 ent substauces are mixed or combined. Sulpbide of zinc was estimated by means of 

 tbe sulpbureted bydrogen evolved on treating tbe accretion witb weak sulpburic acid. 

 No iron was present in tbe solution. 



Traces of tbe silver reported as chloride exist in tbe state of sulpbide. 



Analysis XLIV. Peculiah accretions. 



Elementary analysis. 



Eational analysis. 



Per cent. 



Load 25.9530 



Zinc 53.3294 



Silver 0.0944 



Cliloriue with traces Br, I 0.0350 



Sulphuric acid 0.2866 



Al'senious acid 0. 071 5 



AntiiuoDiaus acid 0. 0505 



Osygen 13.7513 



Sulpbiu- 2.7254 



Peroxide of iron 1. 3sl5 



Alumiua 0.3J85 



Lime 0.2007 



Il.-I3uesi;i 0.1588 



SUioa 1. 5770 



Loss 0.0504 



Total 100.0000 



Silver ounces to ton.. 27. 5327 



Gold Tiaceonly 



Sulphide of lead 



Sulphide of zinc 



Mixture — 



Osideof zinc 



Sulphate of lead 



Oxide of lead "j 



Arseuious acid .. >iu combination 



Autiuiouious acid J 



Chloride of lead, with traces PbBr, Pbl. 



Chloride of silver, with traces Aij:Br, Aj: 



Peroxide of iron (mixed, not combined) .. 



Alumina 1 



Lit e .. -. > partly combined with SiOz-.. 



Magnesia J 



Silica 



Loss 



Total . 



Per cent. 

 17. 8005 

 1. 0670 



C5. 5550 

 1.0891 



10. 5341 

 0.0715 



0. 0565 

 Traces 



0. 129) 



1. 3815 

 0. 3285 

 0. 2007 

 0. 158« 



70 



SECTION V 



THEORETICAL DISCUSSION. 



EEACTIONS IN TUE BLAST-FTTRNACES. 



To form a correct conception of tbe metallurgical reactions in tbe blastfurnaces 

 of Leadville we must take iuto cousideratiou — 



(1) The great altitude at which the smelting operations take jilace, which modi- 

 fies to a considerable extent the volume of tbe blast aud the volatility of volatile com- 

 pounds. 



(2) Tbe manuer iu which the smelting charges are disposed iu the furnace. It 

 has been seen already that the ores aud fluxes are jilaced between two layers of fuel, 

 so that iu all the zones of tbe furnace above those of agglomeration and fusion the 

 reactions take place by actions of gases u])on solid substauces, aud that in a very 

 limited sjiace only reactions by coutact of soli 1 matter can take place. 



