Speisses are alloys of heavy metals like iron, cobalt, nickel and copper
[ White, L.A. "The development of the lead blast furnace at Port Pirie, South Australia", ''Transactions AIME, Vol 188, October 1950, Journal of Metals'', pages 1221–1228.] with arsenic, antimony and, occasionally, tin.
The latter elements lower the melting point to around 1000 °C.
Speisses commonly occur in
lead
Lead () is a chemical element; it has Chemical symbol, symbol Pb (from Latin ) and atomic number 82. It is a Heavy metal (elements), heavy metal that is density, denser than most common materials. Lead is Mohs scale, soft and Ductility, malleabl ...
smelting
Smelting is a process of applying heat and a chemical reducing agent to an ore to extract a desired base metal product. It is a form of extractive metallurgy that is used to obtain many metals such as iron-making, iron, copper extraction, copper ...
operations
[Samans, Carl H. ''Engineering Metals and their Alloys'', 1949 MacMillan] and
copper
Copper is a chemical element; it has symbol Cu (from Latin ) and atomic number 29. It is a soft, malleable, and ductile metal with very high thermal and electrical conductivity. A freshly exposed surface of pure copper has a pinkish-orang ...
smelting
Smelting is a process of applying heat and a chemical reducing agent to an ore to extract a desired base metal product. It is a form of extractive metallurgy that is used to obtain many metals such as iron-making, iron, copper extraction, copper ...
operations.
Speisses are only partially miscible with
mattes, and if there is enough arsenic or antimony in the copper feed to a matte smelting furnace, a separate speiss melt can form.
Speisses show high affinities for
platinum group
The platinum-group metals (PGMs) are six noble, precious metallic elements clustered together in the periodic table. These elements are all transition metals in the d-block (groups 8, 9, and 10, periods 5 and 6).
The six platinum-group ...
metals and
gold
Gold is a chemical element; it has chemical symbol Au (from Latin ) and atomic number 79. In its pure form, it is a brightness, bright, slightly orange-yellow, dense, soft, malleable, and ductile metal. Chemically, gold is a transition metal ...
.
The mass concentration of platinum group metals in the speiss phase is about 1000 times that of the concentration in the matte phase, while the ratio for gold is about 100 times.
Speisses are also immiscible in liquid lead and flow out of lead blast furnaces as a separate phase.
See also
*
Agglomerate (Steel industry)
References
Metallurgical processes
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