[1] This figure indicates thousandths of an inch.
[2] The term “impurity” might in several instances be replaced by the
word “constituent,” since many so-called impurities are purposely added
for conferring desired properties on the metal. It is here taken as
implying elements other than copper.
[3] The temperatures given in Heyn’s diagram require revision in the
light of later knowledge, and have been omitted here.
[4] The treatment of flue-dust is considered later.
[5] Though these actions represent with fair accuracy what occurs on
smelting, there will be indicated later, in the proper place, some
modification, due to interactions of certain oxides and sulphides, in
the furnace.
[6] It might also be possible to assist the concentration in the matte
by the addition of any available oxidised ores or residues.
[7] The chloridising roasting of copper ores is also sometimes employed
in connection with wet processes.
[8] When copper combines with sulphur.
2Cu : Cu_{2}S :: 2 × 63·5 : 2 × 63·5 + 32
:: 127 : 159
:: 4 : 5 approximately.
When sulphur combines with iron.
S : FeS :: 32 : 56 + 32
:: 32 : 88
:: 4 : 11.
[9] Some flue-dust is also melted down.
[10] The East Butte Copper Mining Company has recently reported the
successful sintering of its flue-dust by Dwight-Lloyd machines. (See
_Mining Journal_, Jan. 6, 1912, p. 21).
[11] Later work on this subject has been published by W.
Wanjukoff:—“Investigations on the Conditions governing the Entry of
Copper into the Slags on Matte-Smelting, on the Chemical Form in which
such Copper exists, and on the Lessening of the Copper Losses in
Slags.” _Metallurgie_, 1912, Vol. x., Nos. 1 and 2, pp. 1–27, Jan. 8
and 22, 1912.
[12] This point will be dealt with in due course.
[13] The iron sulphide of a copper matte is probably the eutectic
of the iron-sulphide : iron series containing about 85 per cent. of
sulphide.
[14] Ducktown Sulphur, Copper, and Iron Company.
[15] These views have recently been controverted in an interesting
paper by G. A. Guess. (“Notes on Pyritic Smelting,” _Engineering and
Mining Journal_, 1912, Jan. 13th, p. 113). He defines Pyritic Smelting
as the production of a Ferrous Silicate Slag from Iron Sulphide Ore.
[16] With nickeliferous mattes, the green colour in the flame is
reported by Heywood to persist throughout the whole process.
[17] The case of nickel may be here treated as exceptional. It is
eliminated with difficulty, the nickel and copper tending to oxidise
together on bessemerising.
Transcriber’s Notes:
Underscores “_” before and after a word or phrase indicate _italics_
in the original text.
Equal signs “=” before and after a word or phrase indicate =bold=
in the original text.
A single underscore after a symbol indicates a subscript.
Small capitals have been converted to SOLID capitals.
Parentheses are used for subscripted numbers, for example 2 is
represented by _{2} as in “Cu_{2}O”.
Illustrations have been moved so they do not break up paragraphs.
Inconsistent hyphenation has been left as printed, except “firebox”
has been changed to “fire-box” in the Index to match the spelling
in the main body of the book.
Typographical errors have been silently corrected but other variations
in spelling and punctuation remain unaltered.
In some tables “Number” has been abbreviated to “No.”, “United States
of America” to “U. S. A.” and trailing punctuation has been omitted
to make the rows shorter.
In some equations an ampersand has been used instead of “per cent.”,
again in order to reduce the line length.
The advertisements at the beginning of the book have been re-located
to the end of the book, just before the footnote section.