|20th December 2017, 09:10 PM||#33|
Join Date: Mar 2012
Jambon doesn't analyse the dagger; he uses the measurements by Comelli et al. 2016, (10.8% Ni, 0.58% Co, and also quotes the measurement given by Ströbele et al. 2016 (ref at end), 12.9% Ni.
A few comments on smelting etc.:
"Smelting" is the conversion of ore to metal. For iron, this is typically done by using carbon to bond to the oxygen in an iron oxide, giving CO or CO2 and metallic iron. For a metallic meteoric, there is no need for smelting, because it's already metallic. For any ore, you smelt, by definition, to obtain metal. For iron, the temperature required is well below the melting point of iron, and the chemistry can be made to happen in the solid state, giving a bloom. The is some conflation of "smelting" and "melting" in non-technical usage. You can melt with smelting (just start with metal instead of ore) and smelt without melting (as possible with iron).
When an ore is heated to remove moisture, the process is "roasting", not smelting. Some ores (like limonite) are hydrated, and some are not. Roasting can also be used to make other changes in the ore, such as converting sulphides to oxides. The difference between smelting and roasting is that smelting produces metal and roasting produces a different type of ore. When limonite is roasted, it's converted to haematite, which is then smelting as usual.
The usual early traditional method to smelt limonite (e.g., bog iron) was to roast and then smelt in a bloomery furnace.
For details of the chemistry of smelting and roasting:
or the version with frames if you want to navigate to elsewhere in the document:
I haven't heard of limonite with significant amounts of nickel. The common high-nickel iron ore is laterite. Jambon gives some data for nickel and cobalt content of various laterites.
Comelli et al. 2016: https://doi.org/10.1111/maps.12664
Ströbele et al., 2016:
F. Ströbele, K. Broschat, C. Koeberl, J. Zipfel, H. Hassan, Ch Eckmann
The iron objects of tutanchamun. Metalla
Archäometrie und Denkmalpflege 2016, Göttingen
Sonderheft, 8 (2016), pp. 186-189
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