Paolo Lucarelli presents the history of metallurgy. But is he right when identifying smelting processes before the iron age as a wet path instead of a dry path?
Lucarelli: We do not believe some form of civilization ever existed that has not hosted, in a more or less evident manner, a core that we can define sealed. Because our statement is more precise, say that we seem to find a tight culture if you have the following characteristics:
- The belief is that life-giving energy and intelligence (consciousness) permeates and is the source of universal manifestation, particularly the phenomenon called life.
2. The belief in a possible form of immortality.
3. A representation of the world, subject to intangible law (fate, Heim, etc.).
4. The existence of sufficiently advanced metallurgical technology. At least bronze metallurgy. We will see that a technology that does not know iron smelting is forced alchemical methods, later included under the generic name of “wet.” My opinion: here, Lucarelli points out the ores extraction method. Indeed Ores Sulphides extraction can be divided into roasting and through liquids, mainly water. This last method was the oldest and has been applied moreover on copper and silver sulfides. Copper sulfides were long soaked in water and exposed to air. Acid solutions of CuSO4 are obtained. Treated with iron or steel filings, we have Fe + CuSO4, leading to Cu + FeSO4. This proceeding takes the name of Cementation, which is very proceeding in nature. Lucarelli decided to mainly identify sulfide smelting in a wet way, for he assumes the roasting ( dry way) method was improbable in ancient times due to the need for iron and coal as reducing means. The iron way has been known as precipitation ( roasting in the presence of iron). Strangely enough, the antimony dry way described by Basilius Valentinus was mainly a smelting proceeding by precipitation.
But let’s continue with the origins of metallurgy:
These four characteristics can exist in a particular time and place, alone or associated with others. Still, only the simultaneous presence of all of them allows a complete development of both theoretical and practical, Hermeticism. If we now turn to the documents that official history offers us, we note that only from the seventh and sixth century B.C. we can speak of history as such. Then we have that information fragmented and interpreted, dating back to the third millennium B.C. Beyond this barrier, nothing can be regarded in any sense of history. It is an observation already made by others that do not return, and that has to do with the theory of repeated partial destruction of the Earth, which is part of the tradition.
Here is a brief detour on the oldest metallurgy (1)
The news about prehistoric mines is scarce because mostly erased from mining later: it is, however, clear that the extraction of minerals was carried out regularly since the Upper Paleolithic, at least 10,000 years ago, long before the so-called Age of metal (2). An example is the testimony of the extraction of cinnabar (mercury sulfide) in Vinca, near present-day Belgrade. The oldest metallurgy is undoubtedly the one of lead. The most common of its minerals, the Galena (lead sulfide), blends so quickly that it is enough to get the metal, a fire of dry wood or wood charcoal outdoors, with temperatures less than 800 ° C (3). The oldest documents, in this case, date back to 6500 B.C. in Catal Huyuk in Asia Minor. Other findings in Iraq, Iran, and Egypt suggest the smelting of lead and the beginning of a remarkable expansion in the seventh millennium B.C.
In reality, it is more likely that more than lead, there was an interest in the silver galena and various mineral complexes of lead-antimony-silver. Several articles of the fourth-millennium silver were found in Byblos, Lebanon, Palestine, Warka, Ur in Mesopotamia, Beycesultan, Alikar Huyuk, Korukustan, and Asia Minor. The process of obtaining silver went to the spread of lead ores; the two metals melted together, while other elements in minerals, such as iron, manganese, silicon, calcium, and aluminum, passed mainly in the slag. Silver must then be separated from lead, and this happens through the process known as Cupellation. The alloy of lead and silver is melted in a crucible and maintained at a temperature high enough while blown air is on it. The air oxidizes the lead, turning it into litharge (lead monoxide).
Impurities such as copper, tin, antimony, arsenic, and bismuth are highly oxidized, not silver, which mainly contains even a trace of gold. Once the lead oxide has been absorbed by the walls of the crucible (or eliminated by mechanical means) remains as residue from a globule of precious molten metal. The silver thus obtained always contains a residual amount of lead, varying from 2 to 0.05%. The lid of a silver casket, Nagada from Egypt of 3600 BC, the analysis showed a lead content of 0.45%, so it is undoubtedly an example of metal obtained cupellation. We have dwelt on this process, still in use today, and therefore appears known since ancient times, to note that a civilization that practiced not only has reached a relatively sophisticated level of technology but can not be deceived by alloys that simulate gold or silver: the cupellation it is indeed the most reliable method to recognize the precious metals and separate them from impurities. The question remains how mythology that tells of Saturn-Chronos, lead, eating all their children, not noble metals, but not Jupiter-Zeus, the noble metal does not rust, has been affected by this metallurgical knowledge. (Lucarelli seems to forget the meaning of Time given to Saturn by classical mythology).
At the end of the fifth millennium B.C., we have evidence of an evolved copper metallurgy nourished by its mining industry. A mine certainly exploited since the second half of the fifth millennium is Rudna Glava in Yugoslavia, close to the border with Romania. Not far from Bunar, Bulgaria, copper deposits were exploited very soon by extraction in the open air (4). Ancient copper mines are known in other parts of Europe. One of them was discovered in Chinflon in Spain. Outside Europe, in Veshnovch, Iran, the ore was extracted from a mine with underground tunnels 40 meters long. Another ancient copper mine in ‘West Asia is Kozlu in central Turkey, whose wells had a depth of 50 meters.
We note that obtaining copper from its ores is somewhat tricky. The most common minerals are malachite, azurite and chalcopyrite. The first two can be reduced to metal at temperatures below the copper melting point (1083 C), but this is scattered and not available until the temperature does not rise enough to melt and transform the gangue, consisting of rocky minerals in the state slag fluid: the result shows two immiscible liquids on the bottom of the furnace. Fusing all these minerals requires a temperature of about 1200 ° C. Chalcopyrite, the most commonly used, requires roasting.
The early founders of the Eastern Mediterranean generally proceeded by filling out a stone oven with alternating states of charcoal and mineral combined with a flux. This tended to dovetail with the gangue and away from the metal in a hot oven. In many minerals, the slag was composed of silicon oxide in various forms. The flux was then a suitable iron oxide, hematite, that the oven temperature was combined with silica, forming a silicate of iron. If the ore departure had a significant percentage of arsenic, which was obtained was not copper. Still, natural bronze, had the advantage of a greater hardness: so arsenical copper ores were preferred until, in the second millennium, it wasn’t discovered that tin hardened copper as arsenic did, but with less toxicity. Early in the second millennium, tin bronze manufacturing exceeded that of arsenic bronze.
Towards the end of the second millennium, iron began to replace the production of bronze tools and weapons. However, this should not be considered a technological breakthrough but rather a response to a sudden scarcity of bronze, probably due to a disruption in Tin supply: indeed, bronze presented significant advantages compared to iron and thus only need might explain this unsatisfactory replacement.
The first metalworkers extracted iron from ore, mainly hematite and magnetite, using a process similar to that used for copper. But there was a significant difference. Iron does not melt at temperatures below 1537 ° C, and the maximum temperature reached in furnaces in use at the time was around 1200 ° C. The melting of iron ore at that temperature does not give a molten metal bath but is mixed with a spongy mass of iron oxide and silicate. Following the hammering at the forge transformed, with a sort of mechanical pressing, the porous solid iron in a continuous structure of iron particles here and there interrupted by not removed slag inclusions. This was the starting material from which the blacksmith extracted the objects through additional heating and hammering. What the smith kept working was a lousy substitute for bronze. Indeed, the iron thus obtained is a soft metal, much less resistant (5). Consider then that bronze could be melted at the temperatures reached at the time and corrodes slowly, while iron corrodes rapidly with often severe damage. Therefore that situation was not to be treated as a success, at least for that period (6), but then certainly had to begin a study to improve the performance of iron and to increase the temperature of ovens, which in time led to success.
There remains, therefore, to conclude that we can study only clues and traces, the image of a developed world, which has a rudimentary technology for anything that has acquired considerable familiarity with processes and furnace metal, which can recognize and manipulate chemical compounds, whose remains valuable evidence of civilization indeed not primitive.
- To see this part in particular: L.B. Iovanovic. The origins of copper in Europe, “Le Scienze” No 143. N.H.Gale and Z.Stos-Gale Lead and Silver in the ancient Aegean ‘The Science’ n.156. R. Maddin, GDMuhly and TSWheeler. How the Iron Age began, “The Science” and the literature quoted n.113.
- The beginning of the Bronze Age Ancient (EBI) is around 350 a. C.
- This temperature is well above the melting point of lead metal is 327 ° C.
- Culture Karanovo VI, late Chalcolithic.
- This iron has a tensile strength of about 28 kg. \ Mm2, only slightly higher than pure copper (22 kg. \ Mm2). The process of hardening caused by continual hammering can bring strength to 70 kg. \ Mm2. However, 11% tin bronze has been cast with a tensile strength of 48 kg. \ Mm2 after cold working can reach 84 kg. \ Mm2.
- Iron was not cast until the mid-first millennium A. C when the process was carried out for the first time by Chinese people in the Far East.