PYROTECHNOLOGY AND INVENTION OF POTTERY

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1 1 PYROTECHNOLOGY AND INVENTION OF POTTERY PYROTECHNOLOGY Cooking of food 100,000 years ago Annealing stone 25,000 years ago Baked clay 9,000 BC Plaster 9,000 BC Smelting of ores 6,000 BC Glaze 4,000 BC Glass 2,000 BC CHEMISTRY INTRODUCED BY PYROTECHNOLOGY Oxidation: Burning organic material. Reduction: Reducing metals from their ores Aggregation: Preparation of alloys, pottery Heat Separation: Distillation ACHIEVEMENTS PROVIDED BY PYROTECHNOLOGY o C: Roasting of gypsum (CaSO 4 ) to obtain plaster o C: Structural water of clay is lost, clay is irreversibly changed o C: Vitrification of clay is completed o C:Smelting of most metals from its ores o C:Extraction of iron from its ore, turning silicates into glass

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3 3 ANATOLIA DEVELOPED PYROTECHNOLOGY VERY EARLY BECAUSE Crucial raw materials were available Urbanization was broad and intense Complex pattern of international trade from Lower Danube through Red Sea was available which brought physical and social enviroment into meaningful interactions CLAY Any earthly material when pulvarized and mixed with water becomes plastic and turns rigid upon drying and developes harness and strength upon heating. They are formed by weathering of silicate rocks of feldspathic inorigin which are aluminum silicates of potassium, sodium and calcium. FORMATION OF CLAY Primary clay is formed by natural chemical action on feldspathic rocks CaAl 2 Si 2 O 8 + 3H 2 O + 2CO 2 Anorthite Al 2 Si 2 O 5 (OH) 4 + Ca(HCO 3 ) 2 CLAY FORMATION Kaolinite (Al 2 O 3. 2SiO 2. 2H 2 O) Secondary clays are sedimentary and are transported from their source

4 4 SILICATE TETRAHEDRON CLAY STRUCTURE CLAY IMPURITIES Kaolinite crystalls

5 5 PROPERTIES OF CLAY Plastic Properties are due to: a. Plate like structure b. Small particle size c. Presence of water (15-30%) Drying properties :Evaporation of water will cause shrinkage and hardening. Firing Properties: a o C, chemically combined water leaves b. 800 o C, clay structure breaks c o C, new crystal phase forms CLAY-WATER MIXTURE CLAY SHRINKAGE FIRING CLAY

6 6 POTTERY MAKING POTTERY 1. Preparation of clay 2. Modeling of object 3. Drying phase 4. Firing a. Oxidation ( o C) b. Dehaydration ( o C) c. Baking (above 600 o C) d. Vitrification (above 800 o C) Pottery with 1:1 clay And dung mixture HAND MADE POTTERY Pottery turns black Upon firing

7 7 3rd MILLENNIUM GÖLTEPE POTTERY Mass produced Uruk bewelled rim bowls (BRB) NEOLITHIC POTTERY FROM KÖŞK HÖYÜK, NİĞDE POTTER S WHEEL First pottery was made by hand using series of coils or slabs of clay The first evidence for potters wheel was in Mesopotamia around 3400 BC. Wheel thrown pots generally have spiral ridges and striations.

8 8 POTTERY MAKING POTTER S WHEEL Pottery making

9 9 POTTERY KILNS 1. Domestic fires 2. Bon fires 3. Updraughtg kilns 4. Downdraught kilns 5. Muffle kilns POTTERY KILNS POTTERY KILN PYROMETRIC CONES

10 10 ARCHAEOLOGICAL STUDY OF POTTERY WASHING POTTERY LABELLING

11 11 CLASSIFYING POTTERY DRAWING REPAIRING POTTERY TYPES OF POTTERY TERRACOTA: All brown, red, yellow porous (5-15%) pottery. Fired at >900 o C. EARTHENWARE: Usually glazed, 3-10% porosity, fired at o C. STONEWARE: Highly vitrified, red, cream, brown and gray in color. Porosity 0-5 %, fired at o C. PORCELAIN: Translucent, very strong, porosity <2%, always white with a glaze, fired at o C.

12 12 CHARACTERISTICS OF POTTERY Texture Shape Quality Color Designs Glaze Decora0ons Strength H A L A F P O T T E R Y BLACK BURNISHED KARAZ (KURA ARAXES) POTTERY Hacilar pottery

13 13 2nd MILLENNIUM ANATOLIAN POTTERY BLACK BURNISHED POTTERY YORTAN PHYRIGIAN POTTERY 1st MILLENNIUM BC

14 14 DEPAS FROM TROY (3rd. MILLENNIUM BC) AMPHORAS PALEOLITHIC ART

15 15 MOTHER GODDESS FIGURENE FROM ÇATALHÖYÜK FIGURENES FROM NEOLITHIC HACILAR CLAY CASTING MOLDS Clay mold from EBA Tarsus (Gözlükule)

16 16 GÖLTEPE CRUCIBLES Cuneiform writing on clay tablets Clay Tokens

17 17 YILDIZ PORSELEN PREPARING CLAY Ball mills MOLDS FOR CUPS

18 18 POTTERY KILN FINAL DECORATIONS İZNİK TILES İznik porcelein Chinese porcelein