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Such peoplc and their aucceaaora were able to aaaeaa materiał and lts potentlal. They had status ln their aoclal llfe and patronage to product superior products, both for war and for the aeathetlc sense ln formę of decoratlon and design. They would have recognlsed the need for change ss casslterlte froa easy placer deposlts effectlvely disappeared wlth the need for journeylngs further and further afield. In produclng iron ln morę con-plex furnace structures at higher teoperatures and wlth changea ln manlpula-tive techniąues givlng morę carburlaation external to the blast zonę, superior materiał would be produced whlch began to have strength propertlea at least as good as bronze, for Iron contalnlng carbon can be progreasively cold-worked and annealed to the same hardness as bronze for a sword. Separate carburisa* tlon uslng a charcoal hearth after Initial forging of the bloom could also have emerged as part of a hot forging procesa for blades. Eventually, lmpatient to cool down such carburised hot metal, dowaing into cold water from bright red heat gave the salth a remarkable materiał, extremely hard and brlttle, partl-cularly at the thin cuttlng edge whlch could be progresslvely softened and toughened by reheating, and the true 'steel' age was bom, probably ln Egypt, around 900 BC.

Reference

Bachaann, H G & Rothenberg, B 1980. Die Verhuttungsverfahren von Slte 30. In Antikes Kupfer im Timna-Tal in der Arabah (Israel), eds. H G Conrad & B Rothenberg, 215-236. Bochum: Der Anschnltt, Belheft 1

METKO DS OP O RE ROASTING AMD THE PU RM AC ES USED

J R Marechal (translated by P T Craddock)

Le Mlramar, 4 Avenue Poch, P-J4390 Cabourg. Franca

Abatract

Thla paper deala wlth the proceas and structural remalns of ora roaating aa applled to both non-ferrous and ferroua orea ln Europę, partlcularly Prance. over the past two thoueand yeara. Most orea require a prellminary roaat ln alr prlor to eneltlng to break down compounds such as sulphldes and carbonatea, to evaporate molsture, or Just to prepare them for smelting. The proceas and lts furnacee have so far recelved scant attentlon by thoee atudylng anclent metallurgy and the archaeo-logy of metal smelting sltes.

Keywords:    ROASTING. PURMACE. PRANCE, KILN, ORZ.

IRON, COPPER, SILVER, LEAD, SILVER-LEAD. SMELTING. SPEISS. MATTE

Introduction

The flrst operatlon that ores used to undergo was usually heatlng to a temperaturę beIow that necessary to melt the metal or the gangue. We will cali this process by the morę specialised narae roasting, durlng whlch a Chemical change takes place. This will be either an oxidisation (of sulphldes - a sulphatising roast or dead roasting depending on che degree of oxidisation), a chlorination (when sodium chloride is added as ln tbe case of argentiferous ores), or a calcination (when there is only decomposition as ln the cases of carbonates, sulphates. arsenates etc). These changes can take the form:

1    Agglomeration or sintering as ln the treatment of some galenas

2    Volatilisation as ln the case of sulphldes. arsenides and antlaonldes

3    Concentration by partial oxidisatlon of the iron and the foraatlon of mattes and speiss.