54 SMELTING OF CUPREOUS PYRITES. 



From these data Mr. Gneniveau undertook a complete 



analysis of tliis specimen of the scoriae of Chessy. 



Its external Its external characters were the same as those of the scoriae 



c\aracterb. No. 1. Its specific gravity was 3*61 . Assayed with borax 



it gave 23 per cent of iron, without any signs of copper. 



Analysis. Five grammes, well powdered, were treated with concen- 



Treated with tr^ted muriatic acid, mixed with a little nitric. The whole 



concentrated 



muriatic acid, Coagulated mto a jelly. On this water was poured, it was 



and a little ni- boiled, and fresh acid was added ; by which means a very- 

 white residuum was obtained. The decanted liquors were 

 mixed, and evaporated to dryness, in order to separate the 

 silex completely from the muriatic acid. Water being add- 

 ed, and filtered, a residuum was collected, which Contained 

 no sulphur, and weighed 1'75 ^^r. after having been exposed 

 to a red heat. This was fused with very pure caustic potash ; 

 and the whole of the compound being soluble in muriatic. 

 Residuum acid, Mr. GuenWeau inferred, that the residuum was very 

 pure silex. pure silex, without any mixture of sulphate of barytes. 

 Muriatic solu- ' The muriatic solution gave with sulphuric acid a precipi- 

 ed^Jiirsur*' tate of 0-90 gr. of sulphate of barytes, with which he ascer- 

 pburic acid, tained no sulphate of lime was mixed, and which was heated 

 red hot before it was weighed. The same solution was treat- 

 and hidrosul- ^^ with'hidrosulphuret of ammonia, which precipitated the 

 phuret of am- i , • r • • ■, • ^• i 



monia. metals and alumme, leaving \n solution lime and magnesia. 



The sulphurets were roasted, and afterv/ard dissolved by 

 pitro-muriatic acid : and lastly, the sulphur and sulphuret- 

 ted hidrogen were separated from the preceding liquor. 

 He had then two soUitions ; one. A, coiituining lime and 

 magnesia ; the other, B, containing the metals and alu- 

 miiie. 

 Lime thrown From tljie solution A the lime was thrown down by oxalate 

 down by ox2t- of aminoiiia; and the precipitate, being strongly calcined, 

 j^^j^ ° left 0*18 gr, of caustic lime. The magnesia, which re- 



and magnesia rained, was precipitated by potash ; and, after being cal- 

 by ijotash. cined, weighed 0*1 gr. 



Iron and alu- The solution B was treated by ammonia, an excess of 

 mine precipi- which dissolved the zinc and copper. The oxide of ir<m 



tated by am- t i i • i • i ^ n t t i 



mouia, and se- «-na the alumme, which tell down together, were separated 



paratedbypot- by liquid caustic potash, assisted by heat. The red oxide 



of iron after calcination weighed 2*30 gr. ; and the alumine, 



after 



