Tin and Copper from Bell-Metal. &f 



method pointed out by Fourcroy was deemed the most adr 



vantaffeous 



The method pointed out by this great chemist, which 

 was universally adhered to, consisted in oxidizing one part 

 of the bell -metal from which the copper was to be extracted, 

 and uniting, by long continued agitation, the oxidized por- 

 tion with another quantity of the same metal rendered fluid 

 oy fusion. The oxygen of the oxidized metal became thus 

 transferred to the fused tin of the merely melted bell-metal; 

 and the copper, at least a considerable quantity, was se- 

 parated. 100 parts of bell-metal treated in this manner 

 yielded from 50 to 60 of copper, besides a considerable 

 quantity of slag, vitreous dross or glassy oxide, consisting 

 of oxide of copper and oxide of tin. 



The complete reduction of this vitreous oxide proved ex- 

 tremely difficult : the great excess of oxide of tin which it 

 contained prevented its complete fusion ; the reduced par- 

 ticles of copper, in whatever manner the reduction had been 

 accomplished, could not sink through the viscous matter, and 

 the particles of metal could not be collected into one mass ; 

 at least no cecononucal method could be advised which could 

 be adhered to in the large way. Thus several millions of 

 capital remained as dead stock, and it became a national 

 question, Whether it would not have been better never to 

 pursue this attempt of procuring copper from bell-metal, 

 than to sacrifipe the original compound ? 



Several attempts were made to rendeT the prodigious 

 quantity of slag or vitreous refuse, which was soon pro- 

 duced, useful for other purposes : but they all failed, and 

 no hopes remained of bringing them to account ; except of 

 reconverting them again into bell-metal by a fresh addition 

 of metallic copper. 



In contemplating this subject I persuaded myself that 

 the decomposition of bell-metal was, perhaps, possible by 

 completely converting one of its compounds into a perfect 

 glass of oxide. Before I attempted this, I reduced the slag 

 obtained in Fourcroy's process to the metallic state, in order 

 1p learn its precise nature. The result was a white brittle 

 metal, 



I then took 3 cwt. of this metal and oxidized two of it, 

 in order to reserve the other third for deoxidizing the copper 

 of the first oxidized part, by abstracting from it its oxygen, 

 by the admixture of the third unoxidized portion. The 

 product was a mixture of oxide of tin and particles of me- 

 tallic copper slightly adhering together, from which the, 

 greatest part of the oxide of tin could be separated by mere 



ablution 



