331
oheets are to have a very great size, furnaces somewhat different are had recourse to.J are from 12 to ,15 feet long, and 5 wide. See Brass.
ihe copper, by successive heating and lamination, gets covered with a coat of oxyde,Which is removed by steeping the sheets for a few days in a pit filled with urine ; they|'* e ^ iGn put upon the sole of the heating furnace. Ammonia is formed, which acts onthe copper oxyde, and lays hare the metallic surface. The sheets are next rubbed witha piece of wood, then plunged, while still hot, into water, to make the oxyde scale off;ar *d lastly, they are passed cold through the rolling press to smooth them. They are noweutsquare, and packed up for home sale or exportation.
The following estimate lias been given by MM. Dufrenoy and Elie de Beaumont of
the
expense of manufacturing a ton of copper in South Wales.
£ s.
12| tons of ore, yielding 85 per cent, of copper 55 020 tons of coals - - - - 8 0
Workmen’s wages, rent, repairs, &c. - - 13 0
d.
0
0
0
76 0 0
The exhalations from the copper smel ting works are very detrimental to both vegetablehd animal life. They consist of sulphurous acid, sulphuric acid, arsenic, and arseniousti? 1 . Tar ious gases and fluoric vapors, with solid particles mechanically swept away intofte air j besides the coal smoke. Mr. Vivian has invented a very ingenious method ofPassing the exhalations from the calcining ores and matts along horizontal flues, or ratherJ> a leries of great dimensions, with many crossings and windings of the current, and ex-*i * u *' e during the greater part of the circuit to copious showers of cold water. By thisthe fl atlC * P ower f u l system of condensation, the arsenic is deposited in the bottoms ofhues, the sulphurous acid «s in a great measure absorbed, and the nuisance is re-■narkably abated.
Sin lr *'°^ ow ‘ n ? figures represent certain modifications of the copper calcining and®bug copper furnaces of Swansea.
in \vlf' ' s l ^ e secl i° n the roasting furnace lengthwise; fig. 303, the ground plan-;“ lc h a is the fire-door; b the grate; c the fore-bridge; d the chimney; e e working303 * 305
apertures on each of thelong sides of the furnace,through which the ore is in-troduced, spread, and turnedover; f f cast-iron hoppers;g g openings in the vaultedroof; h the hearth-sole; i iholes in this; k a vaultedspace under the hearth. Thehearth has a suitable ovalshape, and is covered witha flat arch. Its length is16 feet, breadth 13J, mean
p ig. v
* n which a’hfif kfloRudinal section of the melting furnace; fig. 306, the ground plan,flpening s . /' ti.' 6 lre door ; b the grate; c the fire bridge; d the chimney; e the side” e melted rn„f . Wor fli n -i doors; g the raking-out hole; h iron spouts, which conductThe meltin' r ,nt0 P ils filled with water.
' urna ce is altogether smaller ; but its firing hearth Is considerably larger