Rostoker, W., Pigott, V.C. and Dvorak, J.R. Direct Reduction to Copper Metal by Oxide-Sulfide Mineral Interaction 1989 Archeomaterials 3: 69-87. (original) (raw)
Related papers
Over the last decade, our understanding of the first copper-smelting processes has considerably evolved, thanks mostly to a dramatic increase in available archaeological and the related archaeometallurgical data. Copper- smelting activities from the Late Neolithic to the very first phases of the Early Bronze Age (EBA) have been discovered and investigated on some 20 archaeological sites located in the Old World, from the Iberian Peninsula to the Iranian plateau. By summing up most recent studies done in France by the author and by reviewing the published literature concerning the other areas, the present paper reports and discusses the prominent technical features of what may be called, for the sake of convenience, the ‘chalcolithic’ copper-smelting processes. The main finding of this survey is the lack of technological consistency encountered at the beginning of copper extractive metallurgy, including quite technically advanced processes; this supports the considerable variety in copper-production modes reported by others.
Kinetics of iron–copper sulphides oxidation in relation to protohistoric copper smelting
Journal of Thermal Analysis and Calorimetry, 2011
This article deals with one specific step of the copper extractive metallurgy process: the roasting of iron–copper sulphides. It aims at shedding light on an archaeological issue: the reconstruction of the copper extractive metallurgy processes during protohistory (IVe–IIe millennium BC). Experimental simulations are performed at laboratory scale by modelizing the conditions of protohistoric furnaces. Kinetic of roasting is studied by thermogravimetry combined with the physico-chemical analysis of synthetic products. The influence of two parameters is studied: (i) the temperature (773, 973 and 1173 K) and (ii) the granularity of the roasted ores (1 mm and 100 μm). In each case, the chemical mechanism governing the oxidation of iron copper sulphide is proposed. Apart from one extreme case (∅ = 1 mm; T = 773 K), it is showed that kinetic is controlled by the transport of molecular oxygen (O2) from the gas to the grain surface. Moreover, we prove that, in some cases where the diffusivity of gaseous oxygen is low, roasting can be accelerated by the presence of an oxide, which constitute an in-situ source of oxygen. Theses experiments support the hypothesis that such a technique could have allowed a roasting process where iron and sulfur were removed by the solid oxygen instead of the gaseous oxygen. These results allow to validate a one-step copper smelting process starting from sulphidic ores, and to identify the experimental parameters of this process.
Smelting Experiments with Chalcopyrite Ore based on Evidence from the Eastern Alps
Metalla, 2020
In order to assess the fractionation of copper isotopes during smelting under reconstructed conditions, smelting experiments with chalcopyrite ore were conducted in built furnaces based on archaeometallurgical evidence from the Bronze Age Eastern Alps and ethnographic examples from Nepal. Two experimental series, S2 and S4 were chosen for analysis. Each series consisted of a number of roasting and smelting experiments with different experimental parameters, and both series yielded metallic copper. Each type of experiment, their outcomes, and observations made during them are described in detail to facilitate future experimental work. Both series differ significantly in their outcome. XRD analyses and chemical analyses were carried out to reveal the reasons for the observed differences. The chemistry of the obtained matte shows that roasting is pivotal for a successful smelting process and that two cycles of matte roasting and subsequent smelting can be sufficient to remove most of the sulphur and iron from the matte. Furthermore, different conditions in the shaft furnaces resulted in a more efficient oxidation of iron in series S4. During the subsequent smelting of the matte in the pit furnace, it was possible to extract larger amounts of metallic copper and sponge copper, as well as to produce a thin well-melted plate-like slag. The pit furnace did not always show clear traces of metallurgical activity and thus might not be identifiable in the archaeological records without chemical analysis of the pit lining and surrounding soil. Although more trials are needed to replicate the process, these experiments give a strong hint towards the reconstruction of the matte smelting process in the Bronze Age alpine area.
From the end of Chalcolithic times (end of the 4th millennium BC) up to the end of the Bronze Age (1st millenium BC), copper production increases dramatically in Western Europe. However, due to the scarcity of technologyrelated archaeological data, the technological background sustaining the transition to mass production modes remains poorly understood. The main archaeological clues concerning metal production stem from the metallurgical waste, namely copper slags. Those complex materials may be a genuine chemical footprint of the process. In particular, it may bring new insights on one main issue of the process reconstruction: the origin of the oxygen in the system. A new analytical methodology based on both mass-balance calculation and quantification of Fe3+ contents in copper slags (Mössbauer spectroscopy, electronic microprobe and Synchrotron μ-XANES at the Fe-K-edge) has been set up. This methodology enables us to distinguish between the solid and gaseous sources of oxygen in a broad range of working conditions, thus yielding new features for the understanding of the first smelting processes dealing with copper sulphides in Western Europe 4000 years ago.
Post-Medieval and Modern Copper Smelting
2010
This report investigates a range of copper smelting remains which are derived from known technologies in use during the Post-Medieval and Modern periods. The material was investigated in an attempt to establish criteria for the identification of similar remains from the archaeological record.
In the Late Bronze Age, the extractive metallurgy of copper in north-eastern Italy achieved a peak of technological efficiency and mass production, as evidenced by the substantial number of metallurgical sites and the large volume of slags resulting from smelting activities. In order to define the technological features of the Late Bronze Age metallurgical process, more than 20 slags from the smelting site of Luserna (Trentino, Italy) were fully analysed by means of optical microscopy, X-ray powder diffraction, X-ray fluorescence spectrometry and scanning electron microscopy. Three different slag types were identified based on mineralogical and chemico-physical parameters, each being interpreted as the product of distinct metallurgical steps. A Cu-smelting model is proposed accordingly.
Shaft furnaces, fed with ores and charcoal, are commonly built up for archaeometallurgical experiences. The smelting processes of wrought iron production from iron ore and of molten copper from malachite in a small furnace are described and interpreted in light of free energy changes. As the most common ores of copper are Cu and Cu-Fe sulfides, previous roasting processes have to be considered in order to separate copper from iron and to obtain oxides.
Late Roman copper smelting in Polis Chrysochous, Cyprus (Sdralia et al 2023, JAS Rep 48)
Journal of Archaeological Science: Reports, 2023
Two Late Roman slag heaps located near Polis Chrysochous, western Cyprus, were studied to reconstruct the technological processes of copper production. This is the second richest mining region on the island. The Pelathousa slag heap (4th-6th century CE) is located at the foothills of the Troodos Mountains, about 5 km inland from the coast, while the Argaka slag heap (3 rd-8 th century CE) is situated by the coast. An assemblage of 112 slag pieces collected from the two slag heaps was macroscopically examined. Subsequently 49 of the samples were chemically analysed using Hand Held portable X-ray Fluorescence (HHpXRF). A smaller subset of the analysed samples were selected for optical microscopy and Scanning Electron Microscopy with Energy-Dispersive Spectrometry (SEM-EDS). The chemical and microscopic analysis showed that the samples from both slag heaps have a similar composition, including a wide variability in manganese content, which ranges from less than 1 wt % to almost 40 wt%. Manganese has most likely been added as a flux procured from the umber deposits of the Pera Pedi formation which is readily accessible from the nearby mines. The prevalence of sulfide inclusions across all samples indicates that the slag assemblage derives exclusively from copper-matte smelting. The results are then discussed to understand the difference in manganese content, and the organization of copper production within the landscape.
A selection of glassy copper slags from Xinjiang, NW China were analysed by optical microscopy and SEM-EDXA. The results indicate that a very rich copper ore was smelted, probably pure copper sulphide with a gangue rich in feldspar and quartz. The slag is dominated by silica, lime and alumina, which together contribute 90–95wt%. The redox conditions are discussed, including the formation of metallic iron and iron phosphide within the copper metal, and the melting temperatures are estimated to be at least 1300°C, based on the bulk composition of the glass. The combination of redox conditions and high temperature indicates that the smelting would have taken place in a blast furnace, probably bellows-blown. A single radiocarbon date from charcoal trapped in the slag places the operation in the 18th century AD, well after the widespread adoption of blast furnaces in China. Despite the apparent large scale of the operation there are no historical records or local memories of such an operation.
Researches on Copper. History & Metallurgy
The present volume is a collection of selected papers dealing with the history and extractive metallurgy of copper published by the author and his co-workers during the period 1963 – 2009. In addition new chapters were specially written for this collection. 1 General 1.1 History of Copper on Postage Stamps, Metall 57 (1–2), 61–64 (2003) 1.2 The Future of Copper Metallurgy, Mineral Processing & Extractive Metallurgy Reviews 15, 5–12 (1995) [Special issue: International Symposium Problems of Complex Ores Utilization, Saint Petersburg 1994 1.3 Copper Metallurgy at the Crossroads, Journal of Mining & Metallurgy [Bor, Serbia] 43B, 1–19 (2007) 1.4 Flash Smelting versus Aqueous Oxidation, Metall (Goslar) 57 (11), 732–738 (2003) 1.5 Recent Methods for the Treatment of Anodic Slimes of Copper Electrolysis, Metallurgia 72, 257–263 (1965) 1.6 Porphyry Copper Ores 2 Pyrometallurgy 2.1 Pyrometallurgy of Copper 2.2 The Reduction of Sulfide Minerals in Presence of Lime, Met. Trans. 4B (8), 1865–1871 (1973) 2.3 Copper from Chalcopyrite by Direct Reduction, J. Metals 29 (7), 11–16 (1977) 2.4 Die Gewinning von Kupfer, Eisen und Schwefel aus Kupferkies Konzentrat durch Reduktion, Metall 28 (11), 1051–1054 (1974) [English translation] 2.5 Direct Reduction. A Possible Route to Copper ?, Min. Magazine (London) 133 (3), 171–172 (1975) 2.6 The Action of Sulfur Trioxide on Chalcopyrite, Met. Trans. 4B (6), 1553–1556 (1973) 2.7 The Action of Gaseous Chlorine on Chalcopyrite, Erzmetall 65 (6), 269–273 (1974) [English translation] 2.8 The Action of Concentrated Sulfuric Acid on Chalcopyrite, Erzmetall 65(6), 269- 273 (1974) [English translation] 2.9 The Reduction of Copper Sulfate and Its Application in Hydrometallurgy, Met. Trans. 4B (5), 1429–1430 (1973) 2.10 Identification and Thermal Stability of Copper (I) Sulfate, Can. J. Chem. 50, 3872–3875 (1972) 2.11 Thermodynamic Stability of Cu2SO4, Met. Trans. 5B (2), 523–524 (1974) 1.12 The Origin of Flash Smelting, Bull. Can. Inst. Min. & Met. 91 (1020), 83–84 (1998) 2.13 Reduction of Binary Sulfate Mixtures Containing CuSO4 by H2, Can. J. Chem. 54, 3651–3657 (1976) 2.14 Flash Converting. An Appraisal, paper 49.2 in Recent Developments in Nonferrous Pyrometallurgy, edited by I.A. Cameron and J.M. Toguri, Canadian Institute of Mining, Metallurgy, and Petroleum, Montreal 1994 2.15 Copper in Poland, Bull. Can. Inst. Min. & Met. 95 (1066), 97–99 (2002) 3 Hydrometallurgy 3.1 Hydrometallurgy of Copper 3.2 Trends in the Hydrometallurgical Treatment of Copper Oxide Ores, Arab Mining. J. 3 (4), 46–52 (1983). Addendum 3.3 Recent Advances in the Hydrometallurgy of Copper, pp. 43–58 in Hydro Copper 2005, University of Chile, Santiago, Chile 2005 3.4 Ammoniumsulfit in der Hydrometallurgie des Kupfers, Metall (Berlin) 28 (2), 129–132 (1974) [English translation] 3.5 Cementation of Copper. The End of an Era, CIM Magazine 1 (4), 99–101 (2006) 3.6 Abandoned But Not Forgotten. The Recent History of Copper Hydrometallurgy, pp. 3–19 in Symposium on Copper Hydrometallurgy, CIM, Montreal 2007. Reprinted in Metall 60 (7–8), 459–465 (2006) 3.7 Action of Nitric Acid on Chalcopyrite, Trans. Soc. Min. Eng. AIME 254, 224–228 (1973) 3.8 Treatment of a Low-Grade Nickel–Copper Sulfide Concentrate by Nitric Acid, Trans. Soc. Ming. Eng. AIME 254, 228–230 (1973) 3.9 Chalcopyrite — Atmospheric versus Pressure Leaching, Metall 61(5) 303–307 (2007) 3.10 Chalcopyrite: Bioleaching versus Pressure Hydrometallurgy, pp. 17–22 in Proceedings International Conference: Metallurgy of the XXI Century. State and Development Strategy. Institute of Metallurgy and Mineral Beneficiation, Almaty, Kazakhstan 2006 3.11 Aqueous Oxidation of Chalcopyrite in Hydrochloric Acid, Met. Trans. 10B, 49–56 (1979) 3.12 Leaching Studies on Chrysocolla, Trans. Soc. Min. Eng. AIME 254, 98–102 (1973) 3.13 The Cyanide Process for Copper Recovery from Low-Grade Ores, Can. Met. Quart. 12 (1) 89–91 (1973) 3.14 Oxidation of Copper (II) Selenide by Thiobacillus ferrooxidans, Can. J. Microbiol. 18 (11), 1780–1781 (1972) 3.15 Solvent Extraction in Hydrometallurgy. A Historical Perspective, Bull. Can. Inst. Min. & Met. 92 (1033), 103–106 (1999) 4 Electrometallurgy 4.1 Electrometallurgy of Copper 4.2 The Future of Copper Electrowinning, pp. 497–505 in Process Intensification Symposium, Canadian Institute of Mining, Metallurgy, and Petroleum, Montreal 1996 4.3 The Anodic Dissolution of Copper (I) Sulfide and the Direct Recovery of Copper and Elemental Sulfur from White Metal, Trans. Met. Soc. AIME 242, 780–787 (1968) 4.4 The Formation of Digenite, Cu9S5, during the Anodic Dissolution of Cuprous Sulfide, Z. Anorg. Allgem. Chem. 361, 222–225 (1968) 5 Kinetics 5.1 Kinetics and Mechanism of Copper Dissolution in Aqueous Ammonia, Ber. Bunsengesellschaft Physik. Chem. 67, 402–406 (1963) 5.2 Kinetics and Mechanism of Leaching Copper Minerals, pp. 176–193 in the Fifth International Copper Hydrometallurgy Workshop, May 13-15, 2009, Antofagasta, Chile. Organized by the Department of Mining Engineering at the University of Chile in Santiago. 5.3 Kinetics of Reduction of Solid Copper Sulfate by H2 and CO, Can. J. Chem. Eng. 52 (3), 369–373 (1974) The collection gives an idea of research conducted during this period in government, academic, and industrial research laboratories. It is hoped that it will be useful for students, engineers, chemists, geologists, and for research workers.