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INTORDUCTION TO ANCIENT
METALLURGY
ANCIENT METALS METAL SYMBOL MPOC BPOC DENSITY GOLD Au 1060 2970 19.3 SILVER Ag 961 2210 10.5 COPPER Cu 1083 2695 8.92 LEAD Pb 327 1725 11.3 ZINC Zn 420 906 7.14 TIN Sn 232 2270 7.28 IRON Fe 1536 3000 7.86
STUDY OF ANCIENT METALLURGY
• Formation of minerals • Exploitation of minerals in antiquity • Development of metallurgy • Metal trade • Impact of metal and metal trade on social,
economic and military history
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ORE SOURCE MINING ORES AND
STONES ORE
DRESSING
GONGUE
ORE
SMELTING
SLAG INGOT REFINING AND
CASTING THE CASTING
HOT AND COLD WORKING
FINISHED OBJECT
STAGES FROM ORE TO FINISHED METAL OBJECT Significant properties of metallurgy to ancient metal smiths
• Color: (determined value) • Luster: (determined value) • Acoustics: (copper gongs, bells) • Casting ability: (mass production) • Hardness: (tool and weapons) • Strength and malleability: (tools and weapons) • Welding and soldering: (flexibility in construction) • Recycling: (remelting)
STAGES IN THE DEVELOPMENT OF METALLURGY
Date BC • First use of native copper 9500 • First evidence for the extraction of metal (Pb) 6000 • Lead glazing 5000 • First copper object made by casting 5000 • First alloys (Cu-As) 4500 • First bronze (Cu-Sn alloy) 3200 • First iron implements (meteoric) 2500 • First evidence for iron smelting 1700 • Full use of steel (carburizing & quenching) 800
ANATOLIA
CHINA
INDIA PALESTINE IBERIA
AEGEAN TROY
CENTRAL EUROPE
BRITISH ISLES
TRANS-
CAUCASIA
IRAN
MESOPO- TAMIA
SKANDI- NAVIA
DIFFUSION OF COPPER METALLURGY IN THE OLD WORLD
EGYPT
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DISTRIBUTION OF SOME METALS IN EARTH’S CRUST*
Cu Ag Au Pb Sn
Surface Rocks 25 0.15 0.01 15 3.6
Continents 82 0.2 0.03 12 2.0
Basement rocks 120 0.3 0.04 6.0 0.9
In ppm
FORMATION OF SECONDARY ORES
DEVELOPMENT OF MINING • Neolithic Age (>3500 BC): Quarries, open workings,
sloping shafts, gradual galleries • Early Bronze Age (3200-2000 BC): Stripping of out-
crops, shafts with staircases • Middle and Late Bronze Age (2000-1200 BC):
Timbering of shafts, drainage, wider galleries. • Iron Age (1st millennium BC): Drainage exits, large
quarries, transportation, ventilation
FIRE SETTING
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ORE DRESSING
Ore dressing is the treatment of ores and mineral products by mechanical, physical or chemical means to separate the valuable minerals from the worthless constituents to increase its concentration
METAL CYCLE
Ore
Metal Metal Artifacts
Production
Smelting Corrosion
SMELTING REQUIREMENTS
• A furnace that can reach high enough temperatures where metals will melt.
• Supply of heat at a sufficient rate to maintain temperatures and conduct the smelting and slag forming reactions.
• Generate a reducing gas that can decompose the metal oxides disseminated in the ore
COMBUSTION OF CARBON
2C + O2 2CO CO2 C + O2 _______________________ C + CO2 2CO
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REDUCTION OF METAL OXIDES�BY CARBON MONOXIDE
1. Reduction of metal ore with CO MO + CO M + CO2
2. Conversion of CO2 back to CO C + CO2 2CO
ANCIENT SHAFT FURNACE
USE OF BLOW PIPES IN ANCIENT SMELTING FURNACES
Human lungs can produce intermitent flow of 40l/min and
10-20 l/min on continuous basis.
This can heat a small area over 1000 oC.
TYPES OF BELLOW
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OPERATION OF POT BELLOW IONIC COMPOUNDS vs METALS
GRAIN STRUCTURE IN METALS
Grain
Grain Boundary
Vacancy
EFFECTS OF TEMPERATURE
ON GRAIN STRUCTGUE
AND MECHANICL PROPERTIES OF METALS
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ALLOYS
Alloys are metallic substances that contain at least two elements. The base element in an alloy is a metal. The minor component of an alloy distribute in the base metal in two ways: a) They may occupy the spaces between the base metal
b) They may substitute for base metal atoms.
HOW CAN THE ATOMS OF TWO DIFFERENT METALS CAN MIX?
Solid solution
Solid mixture
ALLOY vs PURE METAL HARDNESS OF Cu- As ALLOYS
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EARLIEST METAL OBJECTS
Location Object Date (BC) Technique Aşıklı Cu beads 9000 Cold work Zawi Chemi Cu beads 8500 Cold work Cayonu Cu pins 7000 Cold work Çatal Höyük Cu,Pb beads 6000 Annealing
Cu slag Smelting Yarım Tepe I Pb bracelet 5700 Smelting Can Hasan Cu Mace 6000 Cold work Mersin Cu pin, axe 5000 Casting
COPPER BELT OF NEAREAST
SITES OF EARLY NATIVE METALS
1:Can Hasan, 2:Asikli hoyuk, 3: Catal Hoyuk, 4. Hacilar, 5: Yumuk tepe, 6: Nevali Cori, 7: Cayonu, 8: Ramad,
AŞIKLI HÖYÜK METAL BEADS
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CAN HASAN MACE HEAD COPPER SOURCES OF TURKEY
SOME COPPER ORES
Azurite Chalcopyrite Chalcosite
Malachite Cuprite Tenantite
COPPER INGOTS
Uluburun Shipwreck (1350 BC) Rows of ox hide ingots. Bun ingot
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CHALCOLITHIC CULTURES
This is the period that yielded the earliest copper smelting evidence in Anatolia. The period is divided into three roughly corresponding to cultural interactions with Mesopotamia:
• Early Chalcolithic (6th millennium BC) is also known as the Halaf Period.
• Middle Chalcolithic (5th millennium BC) is also known as the Obeid Period.
• Late Chalcolithic (4th millennium BC) is also known as the Uruk Period.
EARLY MESOPOTAMIAN SITES
URUK TRADE NETWORK HACINEBI TEPE
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URUK EVIDENCE IN HACINEBİ
An Uruk house Tokens in stamped container
Beveled Rim Bowls (BRB) Wall cones (Uruk decoration)
METAL FINDS AT HACINEBİ
ARRIVAL OF CAUCASIAN CULTURES INTO EAST ANATOLIA
Evidence for the Caucasian cultures was recognized by the appearance of red burnished Karaz pottery.
MAJOR ELEMENTS ADDED TO COPPER FOR ALLOYING
• Cu-As Earliest copper alloy, accidental • Cu-Sn Bronze, began to appear ~3000 BC • Cu-Zn Brass, also known as orichalcum • Cu-Sb Rare, mostly found in the Caucasus • Cu-Pb Found mostly in cast copper objects (Highly used by the Romans)
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Cu-As ALLOYS First Cu-As alloys appeared in the Near East in the latter part of 4th Millennium BC. Since Arsenic was not known in metallic form, it was believed that these alloys were accidentally produced from smelting arsenic containing copper ores such as: Energite (3CuSAs2S5) Tennantite (Cu3SAsS3) Arsenopyrite (FeAsS) with chalcopyrite (CuFeS2) Sometimes arsenic minerals orpiment (As2S3) or realgar (AsS) were added to copper ore during smelting.
NAHAL MISHMAR
APPEARENCE OF Cu-As ALLOYS ARSLANTEPE
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LOCATION OF İKİZTEPE İKİZTEPE METALS
0
1
2
3
4
5
% A
s
LC EB I EB II EB III MB I
ARSENIC CONCENTRATION OF İKİZTEPE METALS ACCORDING TO PERIODS
DISTRIBUTION OR ARSENIC CONCENTRATION IN İKİZTEPE
OBJECTS
0
10
20
30
40
50
60
70
80
Nu
mb
er
of
Sa
mp
les
< 1.0 1-2 2-3 3-4 4-5 5-6 6-7 7-8 8-9 9-10 >10
As %
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ARSENIC SOURCES FOR İKİZTEPE METALURGISTS
WHY Cu-As ALLOYS WERE ABANDONED
• Roasting of sulfide ores with arsenic caused arsenic to be lost as a sublimate
• Due to the volatility of arsenic, its composition in copper could not be easily controlled.
• The availability of recognizable arsenic rich ores were limited
• Toxic effect of arsenic was detrimental to the health of the smith.
HOW Cu-Sn ALLOY WAS RECOGNIZED?
• Since stannite (Cu2SFeS.SnS2) resembles arsenical copper ores, it could have been accidentally smelted and Cu-Sn bronze could be obtained.
• Insoluble cassiterite during natural oxidation and enrichment of primary ores will remain in the iron hat (gossan). If cassiterite containing gossan is used as flux in copper smelting, tin could be incorporated into copper.
HARDNESS OF BRONZE
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PREPARATION OF Cu-Sn ALLOYS
1. Metallic copper and tin can be melted together at desired proportions.
2. Copper and tin ore cassiterite may be smelted together.
3. Cementation method can be used in which cassiterite is added to the surface of molten copper under charcoal in a furnace where the tin is reduced directly into the melt: SnO2 + C Sn + CO2
EARLIEST BRONZES
OCCURANCE OF BRONZE BEFORE 22OO BC,
OCCURANCE OF BRONZE AFTER 2200 BC
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BRONZES OF ANATOLIA
• Figurines of Tell Atchana in the Amuq plain dated to around 3000 BC
• Bronzes of Troy II, dated to 2800 BC • Bronzes of Alacahoyuk and Horoztepe dated to
the 2nd half of 3rd millennium BC • Bronze objects from the royal tombs at Ur Mesopotamia 2600-2400 BC
MAP OF SOUTH CENTRAL ANATOLIA
AMUQ FIGURINES ALACAHÖYÜK EBA OBJECTS
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ALACAHÖYÜK EBA METALS
11
12
14
0
0
2
4
6
8
10
12
14
Nu
mb
er
of
Sa
mp
les
Cu As>1.0 Sn>2.0 As & Sn
Alacahöyük EBA Metals
Esin 1967
TROY
TREAURES FROM UR
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KESTEL MINE ENTRANCE TO KESTEL
UNDERGROUND WORKINGS
ORE DRESSING AT KESTEL ENTRANCE TO KESTEL MINE
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KESTEL TIN MINE (2800-2200 BC) FIRE SETTING PACKETS AT KESTEL
C‐14 DATE FOR KESTEL CHARCOAL KESTEL MINE PLAN
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GÖLTEPE WORKSHOP
GRINDING TOOLS AT�GÖLTEPE
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GÖLTEPE STORAGE VESSELS TIN METALLURGY AT GÖLTEPE
• Hematite ores that contain 600-700 ppm cassiterite were not utilized.
• The hematite ores found at Göltepe contained 5 times more cassiterite than Kestel ores.
• Powdered hematite ores contained 13 times more cassiterite
• A method must have been developed to recognize the tin content in hematite ores.
VANING KESTEL CASSITERITE VANNED (CONCENTRATED) KESTEL CASSITERITE
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ASSAYING CASSITERITE
GÖLTEPE SMELTING EXPERIMENT
TIN PRILL FROM SEMLTING EXPERIMENT
METAL FORMING �METHODS
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METAL WORKING
• Mechanical: To bring the metal into desired shape, generally by hammering
• Chemical: To change the surface appearance or to join pieces as in soldering.
• Embossing: To increase the surface by hammering the metal into thin sheet and covering the modeled object made of clay or carved wood.
SHAPING OF METAL
• Copper and its alloys can be shaped by repeated hammering and annealing. It can be hammered both hot or cold.
• Iron and its alloys can be forged only when hot. Cooling rate is very critical for the strength of the alloy.
MECHANICAL SHAPING OF SHEET COPPER
SHAPING BY HAMMERING
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SHAPING SILVER PREPARATION OF COPPER BEFORE CASTING
• Blister copper is remelted in a crucible to keep surface area minimum and avoid contact with air.
• Residual inclusions float to the surface and are removed off as a dross.
• The molten metal is polled by unseasoned wood to reduce copper oxide that may have formed during melting back to metal
EGYPTIAN CASTING OF TEMPLE DOORS
Temple door
Cu Ingot Sn Ingots
OPEN MOLDS FROM TARSUS
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OBJECTS THAT CAN BE MADE BY OPEN MOLD CASTING
CASTING AN AXE WITH A SHAFT HOLE
CASTING SHAFT HOLE AXE
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HOLLOW CASTING BY PIECE MOLDS
PIECE �MOLD�
CASTING
CHINEESE BRONZES
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LOST WAX CASTING LOST WAX CASTING
GRANULATION BRAZING
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METAL EMBOSSING MERCURY GUILDING • Mix Gold or silver with mercury to form an amalgam
• Apply the amalgam on the surface of copper object
• Heat the object to evaporate the mercury
• Thin layer of gold or silver coat will remain on copper object.