فهرست مطالب وحید پورزرقان

Undoubtedly, one of the most important alloying elements in the ancient world is arsenic, which played an important role in the handmade alloys of the early Bronze Age. Arsenic copper alloys and arsenic bronzes undoubtedly have a special place among archaeologists and researchers of ancient metallurgy as a man-made alloy. Arsenic as a contaminating element and impurity is scattered throughout the environment and the ancient metallurgist has used it in the production of arsenic copper alloy for ritual and practical purposes. Arsenic appears as a challenging element in the production of these works as well as the special characteristics that it creates on the surface of these works. One of the most important features of this element in casting is the creation of invers segregation on the surface of these works, which creates the phenomenon of arsenic sweat in these alloys. The primary minerals used in making these alloys are Cu2(AsO4)(OH) olivine or Cu3(AsO4)(OH), iron sulfur arsenide FeAsS and Cu3AsS4 enargite, which are obtained either by direct reduction or by co-smelting. have been placed, or that arsenic was consciously used through Speiss, in the production of arsenical copper alloy in the third millennium. The extraction of arsenic metals is done by two methods direct reduction and Co-Smelting. In the direct reduction smelting method, an alloy of copper and arsenic is created from the oxide ore. But due to the fact that most of the primary ores are sulfide ores, metallurgists have used the other way around, i.e. roasting and direct smelting, which regenerates the metal. In the roasting method, oxide ore is produced and sulfur is removed from the composition in the form of sulfur dioxide, and then copper metal is regenerated by direct smelting. From the extraction of these metals, several other products are created along Co-smelting, which include Matt, Speiss and Slag. The main goal of this article is to provide a comprehensive review of extraction methods, considering the importance of copper-arsenic alloys in the field of archeology and Archaeometallurgy, Providing a comprehensive review on extraction methods, physical characteristics of these alloys and the role of arsenic and its effect as an alloying element in the formation of silver surface as well as other side products as a very important issue in the investigation of early bronze age alloys.

Undoubtedly, one of the most important man-made objects in history is copper objects and their alloys, and in this regard, according to the available evidence, its oldest alloy, as copper-arsenic, has an important role in history. the existence of these works in various sites, especially in southeastern Iran since the early bronze age, confirms this claim. One of the most significant strategic site is located in the southeastern of Iran, is the spidej area. It is one of the most important and settlement centers belonging to the second and third millennia BC, which is located 40 km southwest of Bazman. And is located 3 km from Maxsan village. The distance from this area to Iranshahr is about 160 km. significant artifacts were obtained from spidej cemetery as follows: including stamps, ornaments (beads, pins, kohl holder pin, mirrors), agricultural tools, types of weapons etc. This led to the registration of the spidej site at number 6745 in the list of national monuments. In this study, a number of metal objects in spidej cemetery were identified to identify copper-arsenic compounds and the properties of this alloy. To study these objects, the SEM-EDS method was used to identify the microstructure of the metal matrix and the chemical composition of the elements, as well as the metallographic method to study the fabrication technique and phases studies. Instrument analysis of SEM-EDS shows that some objects are made of Cu-As-Zn alloy and some of Cu-As alloy are made by casting in mold and considered as arsenic-containing bronze alloys. Arsenic acts as an excellent oxidant element in metal, reducing the porosity of the alloy and significantly increasing its hardness. Deliberate addition of low levels of arsenic can act as a dioxin in the samples. Also, the presence of sulfide in the impurities of these objects can be due to the use of sulfide ores. The amount of calcium and potassium in the EDS spot analysis of the inclusions indicates that this amount of elements is owing to coal fuel. These elements are considered as flux charge melt and eventually absorb the slag. The SEM images suggest that the impurities in the whole matrix of the metal in a point and elongated from can be the reason for the presence of unrefined copper with spiess in the process of making these works. This discarded waste contains sulfide, arsenide and iron-like compounds. Also, the uniform and high percentage of arsenic 5 in these works shows that the manufacturing process of these alloys has been done by method Co-smelting. Metallographic studies show that physical operation on these works are a repetition of a cycle cold working and annealing work to further ductility these works.

Shahr-I Sokhta is a historical settlement in south-eastern of Iran in the province of sistan-baluchestan, where the first settlement history goes back to 3200 BC. The results of excavations show four cultural-settlement period (I-IV) in this city that is divided into 11 phases. Period (II) goes back to 2500-2800 BC. The history of period (III) is equivalent to 2300-2500 BC, and history of period (IV) is suggested between 1750 and 1800 BC. This archaeological site is located 57 km from Zabol-Zahedan road. This site is registered as seventeenth heritage of Iran in UNESCO. One of the prominent features of this archaeological area is the existence of a lot of pottery shards on the surface of hills. Most of these pottery shards are buff color and have extensive domain from light buff to brick and greenish. Also, red and grey potteries have put in the next classification which the number of them is so little. Archaeological excavations carried out in this site pulled out thousands of pottery shards from the soil that are mostly buff-colored pastes. Also, among the pottery remnants of this 150 hectare site, clay pottery with red and gray paste have been seen. Archaeologists believe that most of the buff pottery shards are locally made. Hence, to determine whether this hypothesis is true, a scientific analysis was done to determine the chemical compositions of the pottery shards. In this paper, 15 pottery sample have been selected which all of them belong to settlement period II-III and goes back to 2200-2800 BC. The samples was tested using instrument analysis XRF to determine the major and trace elements of these potteries. The results analyzed using hierarchical cluster analysis (HCA) to specify pieces of pottery in two group local and nonnative. The results show that most of pottery is locating in a specific group with name of production group, where the samples no. 18259-9, 18265-10, 18266-13, 18273-4, 18271-15 are not locally made and located in another group. Based on the instrumental results, red and grey pottery are not related to Shahr-I Sokhta and probably these potteries are imported from another place.