COPPER 931 



As another advantage arising from the use of this invention, it is found in tho 

 practical carrying out thereof, that the production of a given amount of sulphuric 

 acid is effected by the expenditure of far less nitre than is commonly used, a certain 

 amount of sulphuric acid being formed in tho chamber of the furnace and passing 

 forward in a state of vapour. Thus far wo have spoken of this invention as applicable 

 to the manufacture of sulphuric acid, but it is also applicable to roasting ores of 

 copper preparatory to reduction. In this application the operation is precisely that 

 above described, and will not, therefore, need a repetition of description, it being of 

 course understood that if the ores have been previously used for tho manufacture of 

 sulphuric acid, and contain, therefore, but a small amount of sulphur, the vapours 

 from the chamber d may pass into the atmosphere instead of into the vitriol chamber, 

 if desired. 



On the 14th June 1864, Mr. Peter Spenco and Mr. J. B. Spence effected another 

 patent for ' calcining and smelting copper ores.' This will be fully understood by tho 

 following description : 



' Our invention consists in applying the heat used in smelting copper ores to tho 

 purpose of calcining such materials, and in transferring the calcined ores direct to 

 the smelting furnace. To accomplish these objects, we place the two furnaces in 

 connection with each other, and cause a suitable flue to convey the heat used in smelt- 

 ing to the material to be calcined ; and when this operation is complete, and the 

 smelted ore is removed, we rake the calcined ore direct on to the bed of the smelting 

 furnace. The calcining furnace we at present prefer to use is of that construction 

 for which Letters Patent were granted to Peter Spence, bearing date July 3rd, 1861, 

 No. 1695.' 



In addition to these processes, it may be stated that a company has been established 

 at Oldbury, in Staffordshire, for working the process know as 'Henderson's salt 

 process.' We have been favoured with the following description : 



' The works are erected for the purpose of extracting the copper, and utilising the 

 residue from the Spanish pyrites, imported mostly by the alkali makers, and the 

 sulphur extracted by them for the purpose of making sulphuric acid. We then calcine 

 the ore with salt in such a way as to decompose every trace of copper, and peroxidise 

 the whole of the iron that is not already oxidised during the burning out of the 

 sulphur. We then put the calcined ore into vats or tanks ; and as the chloride of 

 copper is readily soluble, that metal is washed out perfectly clean with hot water, and 

 the residue of peroxide of iron is sold at the iron works in the immediate neighbour- 

 hood. This is used in the puddling furnaces, and answers well for two purposes : first, 

 to keep the pig iron from cutting the bottom of the furnaces, and, secondly, to improve 

 the quality of the wrought iron produced. We sell of this residue about 600 tons per 

 month. The copper is precipitated from the solution by scrap iron, the precipitate 

 run down and refined ; and the whole of the copper is sold as B. S. ingot. We 

 produce 15 to 18 tons of copper per month.' See PYBITES. 



Spanish Process of refining Copper. The refining of copper is well executed at 

 Seville, in Spain ; therefore some account of the mode of operating is required. 



Tho first object is to expel in a reverberatory furnace all the volatile substances, 

 such as sulphur, arsenic, antimony, &c., which may be associated with the copper ; 

 and the second, to oxidise and convert into scoriae the fixed substances, such as iron, 

 lead, &c., with the least possible expense and waste. The minute quantities of 

 gold and silver which resist oxidation cannot be in any way injurious to the copper. 

 The hearth is usually made of refractory sand and clay with ground charcoal, 

 each mixed in equal volumes, and worked up into a doughy consistence with water. 

 This composition is beat firmly into the furnace bottom. But a quartzose hearth, 

 such as a bed of fire-sandstone, is found to answer better, and to be far more durable. 



Before kindling the furnace, its inner surface is smeared with a mixture of fire-clay 

 and water. 



The cast pigs, or blocks of crude copper, are piled upon tho hearth, each successive 

 layer crossing at right angles that which is beneath it, in order that tho flame may 

 have access to play upon the surface of tho hearth, and to heat it to a proper pitch for 

 making the metal flow. 



The weight of the charge should be proportional to the capacity of the furnace, and 

 such that the level of the metallic bath may bo about an inch above the nozzle of the 

 bellows ; for, were it higher, it would obstruct its operation, and, if too low, the stream 

 of air would strike but imperfectly the surface of the metal, and fail to effect, or 

 would at least retard, the refining process, by leaving the oxidation and volatilisation 

 of the foreign metals incomplete. 



As the scoriae form upon tho surface, they are drawn off with an iron rabble fixed 

 to tho end of a wooden rod. 



Soon after the copper is melted, charcoal is kindled in three iron basins lined with 



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