. Transactions. igating the problem it was thought desirable to ex-amine the slags from the reverberatory furnaces from thechemical and mineralogical standpoints. Table m. gives in aconcise way the compositions of these slags, which were pro-duced by smelting calcines obtained by roasting concentratesmixed with crushed limestone, with a certain amount ofconverter-slag, from both basic- and acid-lined analyses represent very careful work with accurate andexact methods, not the methods used in ordinary rapid smelter-work. The regular slags tapped from the furnace are desig-nated a
. Transactions. igating the problem it was thought desirable to ex-amine the slags from the reverberatory furnaces from thechemical and mineralogical standpoints. Table m. gives in aconcise way the compositions of these slags, which were pro-duced by smelting calcines obtained by roasting concentratesmixed with crushed limestone, with a certain amount ofconverter-slag, from both basic- and acid-lined analyses represent very careful work with accurate andexact methods, not the methods used in ordinary rapid smelter-work. The regular slags tapped from the furnace are desig-nated as clean slags. Floaters are masses of loosened fur-nace-bottoms. Blanket slag is a slag which forms on thesurface of the charge and which seems to consist of partly-fusedmaterial. The following additional petrographic notes elabo-rate the identification of the minerals. (I am indebted to P. Berkey for the identification of the minerals in theslags). CONSTITUTION AND MELTING-POINTS OF COPPER-SLAGS. 755. ^ S ^ fn £:» o o l-H 756 CONSTITUTION AND MELTING-POINTS OF COPPER-SLAGS. Slag No. 3.—A dark slag with many roundish light-coloredgrains. One mineral is present in considerable amount. It iscolorless and occurs in round, corroded grains that have neithercrystal-boundaries nor internal structural features. The grainsare fractured. The mineral has good relief and low doublerefraction. It is uniaxial and positive. It is evidently theoriginal undecomposed quartz that has not been fluxed. Theground-mass is glassy, shows strong flowage, and is brown toblack in color. Those portions showing the strongest flowageare brown in color, and portions immediately surrounding thecrystals grains are generally brown. The rest of the field isvery dark and carries an abundance of black metallic particles,very likely magnetite. The lighter color about the quartzgrains seems to show the solution of the quartz into the glassor slag. In a few places large metallic grains occur, probablyma
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Keywords: ., bo, bookcentury1800, bookdecade1870, booksubjectmineralindustries
