Medieval Pb (Cu-Ag) Smelting in the Colline Metallifere District (Tuscany, Italy): Slag Heterogeneity as a Tracer of Ore Provenance and Technological Process
Archaeological investigations of the Colline Metallifere district (Southern Tuscany, Italy) have highlighted several Medieval sites located close to the main Cu-Pb-Fe (Ag) ore occurrences. This study is focused on the investigation of late-medieval slags from Cugnano and Montieri sites using both ge...
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MDPI AG
2021-01-01
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| Series: | Minerals |
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| Online Access: | https://www.mdpi.com/2075-163X/11/2/97 |
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| author | Laura Chiarantini Marco Benvenuti Giovanna Bianchi Luisa Dallai Vanessa Volpi Rosarosa Manca |
| author_facet | Laura Chiarantini Marco Benvenuti Giovanna Bianchi Luisa Dallai Vanessa Volpi Rosarosa Manca |
| author_sort | Laura Chiarantini |
| collection | DOAJ |
| description | Archaeological investigations of the Colline Metallifere district (Southern Tuscany, Italy) have highlighted several Medieval sites located close to the main Cu-Pb-Fe (Ag) ore occurrences. This study is focused on the investigation of late-medieval slags from Cugnano and Montieri sites using both geochemical and mineralogical methods to understand slag heterogeneities as result of ore differences and technological processes. Matte-rich slags present in both sites (with abundant matte ± speiss and frequent relict phases) represent waste products related to primary sulphide ore smelting to obtain a raw lead bullion. The distribution of slags between the Ca-rich or Fe-rich dominant composition, and the consequent mineralogy, are tracers of the different ore–gangue association that occurred in the two sites. Silver is present only in very small matte-rich slags and ores enclosed within the mortar of the Montieri site; wastes derived from silver-rich mineral charges were probably crushed for the recovery of silver. Matte-poor slags found at Montieri represent a second smelting; raw lead bullion obtained from matte slags (both Fe- and Ca-rich) was probably re-smelted, adding silica and Al<sub>2</sub>O<sub>3</sub>-phase-rich fluxes, under more oxidizing conditions to reduce metal impurities. This second step was probably employed for Zn-rich lead ores; this process helped to segregate zinc within slags and improve the quality of the metal. |
| first_indexed | 2024-03-09T04:13:44Z |
| format | Article |
| id | doaj.art-14e114bba967411db5989d69081b4cda |
| institution | Directory Open Access Journal |
| issn | 2075-163X |
| language | English |
| last_indexed | 2024-03-09T04:13:44Z |
| publishDate | 2021-01-01 |
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| record_format | Article |
| series | Minerals |
| spelling | doaj.art-14e114bba967411db5989d69081b4cda2023-12-03T13:56:41ZengMDPI AGMinerals2075-163X2021-01-011129710.3390/min11020097Medieval Pb (Cu-Ag) Smelting in the Colline Metallifere District (Tuscany, Italy): Slag Heterogeneity as a Tracer of Ore Provenance and Technological ProcessLaura Chiarantini0Marco Benvenuti1Giovanna Bianchi2Luisa Dallai3Vanessa Volpi4Rosarosa Manca5Centro di Microscopia Elettronica e Microanalisi, Università di Firenze, Via. G. Capponi 3r, 50121 Florence, ItalyDipartimento di Scienze della Terra, Università di Firenze, Via G. La Pira 4, 50121 Firenze, ItalyDipartimento di Scienze Storiche e dei Beni Culturali, Università di Siena, Via Roma 56, 53100 Siena, ItalyDipartimento di Scienze Storiche e dei Beni Culturali, Università di Siena, Via Roma 56, 53100 Siena, ItalyDipartimento di Scienze Storiche e dei Beni Culturali, Università di Siena, Via Roma 56, 53100 Siena, ItalyDipartimento di Scienze della Terra, Università di Firenze, Via G. La Pira 4, 50121 Firenze, ItalyArchaeological investigations of the Colline Metallifere district (Southern Tuscany, Italy) have highlighted several Medieval sites located close to the main Cu-Pb-Fe (Ag) ore occurrences. This study is focused on the investigation of late-medieval slags from Cugnano and Montieri sites using both geochemical and mineralogical methods to understand slag heterogeneities as result of ore differences and technological processes. Matte-rich slags present in both sites (with abundant matte ± speiss and frequent relict phases) represent waste products related to primary sulphide ore smelting to obtain a raw lead bullion. The distribution of slags between the Ca-rich or Fe-rich dominant composition, and the consequent mineralogy, are tracers of the different ore–gangue association that occurred in the two sites. Silver is present only in very small matte-rich slags and ores enclosed within the mortar of the Montieri site; wastes derived from silver-rich mineral charges were probably crushed for the recovery of silver. Matte-poor slags found at Montieri represent a second smelting; raw lead bullion obtained from matte slags (both Fe- and Ca-rich) was probably re-smelted, adding silica and Al<sub>2</sub>O<sub>3</sub>-phase-rich fluxes, under more oxidizing conditions to reduce metal impurities. This second step was probably employed for Zn-rich lead ores; this process helped to segregate zinc within slags and improve the quality of the metal.https://www.mdpi.com/2075-163X/11/2/97slagsarchaeometryarchaeologymedievalleadzinc |
| spellingShingle | Laura Chiarantini Marco Benvenuti Giovanna Bianchi Luisa Dallai Vanessa Volpi Rosarosa Manca Medieval Pb (Cu-Ag) Smelting in the Colline Metallifere District (Tuscany, Italy): Slag Heterogeneity as a Tracer of Ore Provenance and Technological Process Minerals slags archaeometry archaeology medieval lead zinc |
| title | Medieval Pb (Cu-Ag) Smelting in the Colline Metallifere District (Tuscany, Italy): Slag Heterogeneity as a Tracer of Ore Provenance and Technological Process |
| title_full | Medieval Pb (Cu-Ag) Smelting in the Colline Metallifere District (Tuscany, Italy): Slag Heterogeneity as a Tracer of Ore Provenance and Technological Process |
| title_fullStr | Medieval Pb (Cu-Ag) Smelting in the Colline Metallifere District (Tuscany, Italy): Slag Heterogeneity as a Tracer of Ore Provenance and Technological Process |
| title_full_unstemmed | Medieval Pb (Cu-Ag) Smelting in the Colline Metallifere District (Tuscany, Italy): Slag Heterogeneity as a Tracer of Ore Provenance and Technological Process |
| title_short | Medieval Pb (Cu-Ag) Smelting in the Colline Metallifere District (Tuscany, Italy): Slag Heterogeneity as a Tracer of Ore Provenance and Technological Process |
| title_sort | medieval pb cu ag smelting in the colline metallifere district tuscany italy slag heterogeneity as a tracer of ore provenance and technological process |
| topic | slags archaeometry archaeology medieval lead zinc |
| url | https://www.mdpi.com/2075-163X/11/2/97 |
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