56 SMELTING OF CUPREOUS PYRITES. 



f)om the account given by Messrs. Lemaire and Bouesnel, 

 iu order to render more perspicuous the comparison between 

 the chemical and metal lurojical results. 



Treatment of The greater part of the ore wrouoht at Chessv is verv 

 t be ore of , ^ ^ , n 



Ch<'s>y, which poor "» copper. It is a mixtuve of sulphuretted iron, sul- 

 is very poor, phuretted zinc, pyritous copper, and a small portion of 

 earthy substant es, as quartz and sulphate of barytes. The 

 Pounded, roasf- ore after pounding is roasted by a very economical process, 

 with thr^ddi- '^^^ch saves the greater part of the sulphur contained in it. 

 tioaof scoriu;. It is then smelted, with the addition of scoria? from pre- 

 ceding smeltings, and quartz broken to pieces, the propor- 

 tion of which varies from seven to ten hundredths of the 

 weight of the ore. 



This smelting affords tvro products ; the scoriae, of wliich 

 Matts roasted analyses have been given, Nos. 1 and 3 ; and raatts, or sul- 

 rej.eatedly, phurets of iron and copper. These matts are roasted seve- 

 w'th scoriy; ^^^ times, and resm'elted with scoriae and quartz, but in less 

 and quartz. proportions than at first. By these operations are obtained 

 black copper, matts rich in copper, and the scoiite analvsed 

 No. 3." In all thiBse fusions no oxide of iron is reduced*. 



The 



* Most of the ores and products of the smehing have been subjected 



to analysis, and assayed in the-dry way.' The following ai^e sOriic cH>ie 



results. • 



^ na.yMSoitne ^'j^g ^^ qj._ mailed at Chsssv meagre ore, is separated from \vh,d 



poor ore. - o » i , , 



they cajl the yellow ore, ■which is much more rich, and is lOkstL'd and 



smeltfc'd separfilely. Tjie poor alone is consid.rL'd here. The crude ore 

 roasted by itself, or in the great, most frequently yields ho copper 'ito 

 assaying. Once with four parts bf blaek flux Mr. Gueiiiveau obtain<Hi 

 from it 11 per cent of tolerably pure copper. By oheiuital ^laalysis it 

 never afforded him more than 4 or 5 per cent of copper j but it con- 

 tained from C6 to 55 of iron, accordinj!; as it was miked with the ganjjue, 

 pr piote or less toasted. The mean of the iron may be estimated at 40 

 per cent. 

 * *• The matts obtained fron) the first smelting of the ore amount to seven 



hnndredihs of its weif^ht. They contairt about 25 parts of sulphur, 40 

 of metallic iron, and from i^5 to 27 v{ copper. It is of imj)ortance to 

 observe, that of 45 pirts of iron introduced into tlie furnace not abov;; 

 ij or 4 remain in the m^tt after the fiiSL fusion. The whole of the zipc 

 is volatilised in this oper.tion. 

 Black copper 'pi,^. |natts are roas'td and resmelted, and the products are blaek eop- 

 ai^ rich malts. • • , ^ r ,.■ . • v . . .^ 



per, coiUamuig 1 or 2 per cent oi metallic ironj and rich n^atts, con- 

 taining 



