A supplement to Ures Dictionary of Arts, Manufactures, and Mines, : containing a clear exposition of their principles and practice. . tharge - - - - 0 1 0-8 Calcined dross 008-0 Slags 0 0 5-0 Bone-ash, &c. 0 0 7-0 Transport, &c. 0 11-0 Management, taxes, and interest of plant - - 0 5 10*0 Total - - . - 1 2 3-9 One hundred tons of hard lead treated gave :— Tons. Soft lead 94-90 Black dross 3-72 Loss 1-38 Total 100-00 On comparing the expense of each operation, as given in the foregoing abstract, withthe amounts stated as the cost of each separate process, they will be found to be widelydifferen
A supplement to Ures Dictionary of Arts, Manufactures, and Mines, : containing a clear exposition of their principles and practice. . tharge - - - - 0 1 0-8 Calcined dross 008-0 Slags 0 0 5-0 Bone-ash, &c. 0 0 7-0 Transport, &c. 0 11-0 Management, taxes, and interest of plant - - 0 5 10*0 Total - - . - 1 2 3-9 One hundred tons of hard lead treated gave :— Tons. Soft lead 94-90 Black dross 3-72 Loss 1-38 Total 100-00 On comparing the expense of each operation, as given in the foregoing abstract, withthe amounts stated as the cost of each separate process, they will be found to be widelydifferent; but it must be remembered that the whole of the substances elaborated are farfrom being subjected to the various treatments described. In order therefore to give an idea of the relative proportions which arc passed through LEAD. 699 the several departments, I may state, that in an establishment in which the ores are treat-ed in the Castilian furnace, the following were the results obtained:—One hundred parts of raw ore yield :— Roasted ore .. Hard lead 42 Soft 36 Rich 9 Dross and litharge re-treated 18^ 390. It may be remarked, that for the treatment of ores of good produce, the rererberatoryfurnace and Scotch hearth are to be preferred, but for working minerals of a low percent-age the blast furnace may generally be substituted with advantage. The slag-licarth,from the amount of fuel consumed and loss experienced, is a somewhat expensive ap-paratus, and might in many cases be advantageously exchanged for the Castilian furnace. It is well known that the losses which take place in this branch of metallurgy are,from the volatility of tlie metal operated on, unusually large. In those establishments,however, in which due attention is paid to fluxes and a proper admixture of ores, as wellas the condensation of the fumes, a great economy is effected. In some instances, flues of above five miles in length have been constructed, and themost satisfactory results obtained. T
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Keywords: ., bookcentury1800, bookdecade1860, bookpublishernewyo, bookyear1864
