A text-book of assaying

by C. Beringer; J. J. Beringer

In determining antimony in ore, weigh up 0.5 to 1 gram, and dissolve in hydrochloric acid with, if necessary, the help of chlorate of potash. The antimony is separated as sulphide, redissolved in hydrochloric acid, and oxidised with a crystal of chlorate of potash. Chlorine is boiled off, and the solution diluted with an equal bulk of water. To the clear cold solution potassium iodide is added, and after a few minutes the liberated iodine is titrated with "hypo," as already described. The method only yields satisfactory results when the standard and assay are carried out alike.

FOOTNOTES:

[50] "Modern American Methods of Copper Smelting" (Dr. Peters).

[51] "Journal of the Society of Chemical Industry," vol. v. No. 2.

[52] Lead when present is precipitated on the spiral in the form of a dark powder of dioxide (PbO₂). Manganese is also thrown down on the spiral as dioxide (MnO₂), the solution at the same time becomes violet from the formation of permanganic acid.

[53] See the method given under Examination of Commercial Copper.

[54] CuSO₄ + 4KCy = 2KCy.CuCy₂ + K₂SO₄.

[55] 2CuSO₄ + 3KCy + Am₂O = Cu₂Cy₂ + Am₂SO₄ + K₂SO₄ + KCyO.

[56] 2CuSO₄ + 4KI = Cn₂I₂ + 2I + 2K₂SO₄.

[57] 2Na₂S₂O₃ + 2I = 2NaI + Na₂S₄O₆.