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Showing 2 results for Ceramic Nails

Aminallah Kamali,
Volume 7, Issue 3 (11-2024)
Abstract

The Bahabad zinc smelting site, located 71 km north of Bahabad in Yazd Province, Iran, spanning 220 m² within the Tabas-Posht-e-Badam metallogenic belt, is a key ancient metallurgical center. This study aims to identify the extracted metal, analyze metallurgical processes, and reconstruct the employed technologies through petrographic and geochemical analyses of ceramic nails and furnace slags. Thirty ceramic nails and 20 slag samples were collected, with five samples from each group selected for petrographic study and chemical analysis using inductively coupled plasma optical emission spectroscopy (ICP-OES). Petrographic results revealed that the ceramic nails, made from fired clay, exhibit a porphyritic texture with ~20% quartz and minor calcite, while slags contain fayalite (FeSiO), melilite, pyroxene, and wüstite (FeO), indicating high-temperature, reducing conditions. Chemical analysis showed an average of 1.21% ZnO in nails, confirming their role in collecting zinc vapors as tutia (ZnO) over centuries, and 3.74% ZnO in slags, suggesting incomplete zinc extraction. Low lead (669 ppm in nails, 315 ppm in slags) and sulfur (1053 ppm in nails, 361 ppm in slags) concentrations indicate the use of oxidized ores like smithsonite (ZnCO) or hemimorphite rather than sulfides like sphalerite (ZnS), consistent with the region’s oxidized lead-zinc deposits. Two-tier furnaces, with a lower heating chamber and an upper perforated clay plate holding ceramic nails (10–20 cm long, 2–4 cm diameter), facilitated upward distillation. This technology contrasts with India’s downward distillation (sphalerite, square furnaces) and China’s condenser-based upward method (rectangular furnaces), highlighting Iran’s indigenous innovation using charcoal and ceramic nails. The study underscores the technology’s adaptation to local conditions and its significance in global metallurgical history.

Dr Farzad Mafi, Miss Nazanin Khojastehbehzadi, Dr Mohammadamin Emami,
Volume 9, Issue 1 (8-2026)
Abstract

Owing to its vast and rich mineral resources, the Kerman region is regarded as one of the most significant areas for the identification and extraction of metals in Iran. The city of Bam, located in the southeastern part of this province, has long served as a strategic center linking southeastern Iran with Sistan due to its distinctive geological and geomorphological conditions. Archaeological surveys conducted in the central district of Bam County during 2018–2019 aimed to identify ancient mining areas and metallurgical smelting centers. Drawing upon the results of these field investigations, the present study undertakes chemical and mineralogical laboratory analyses of four ceramic nail samples recovered from four areas associated with metallurgical activities. These analyses were carried out to determine the function of the ceramic nails and to investigate the extraction processes involved. The studied samples were examined through petrographic and geochemical analyses using the ICP-OES method across the four identified sites. Petrographic examination of the ceramic nails indicates high firing temperatures during manufacture and reveals a porphyritic texture containing predominantly igneous inclusions as temper materials. The results of the chemical analyses demonstrate that approximately 72% of the chemical composition of these ceramic nails consists of zinc, thereby confirming the intentional extraction of this metal. The existence of sufficient technological knowledge for the oxidation of zinc and the production of Tutia (zinc oxide) at these sites may indicate the emergence of one of the most sophisticated and technologically advanced metallurgical extraction processes in the ancient world. The analytical results obtained from the ceramic nails recovered from several of these sites further suggest that they were specifically employed in the extraction and production of zinc oxide (Tutia).


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