Copper Roman

Tin [7440-31 -5] is one of the world s most ancient metals. When and where it was discovered is uncertain, but evidence points to tin being used in 3200—3500 BC. Ancient bron2e weapons and tools found in Ur contained 10—15 wt % tin. In 79 ad, Pliny described an alloy of tin and lead now commonly called solder (see Solders and brazing alloys). The Romans used tinned copper vessels, but tinned iron vessels did not appear until the fourteenth century in Bohemia. Tinned sheet for metal containers and tole (painted) ware made its appearance in England and Saxony about the middle of the seventeenth century. Although tinplate was not manufactured in the United States until the early nineteenth century, production increased rapidly and soon outstripped that in all other countries (1). 

Hydrometallurigcal Processes. In hydrometaHurgical processes, metal values and by-products are recovered from aqueous solution by chemical or electrolytic processes. Values are solubilized by treating waste, ore, or concentrates. Leaching of copper ores in place by rain or natural streams and the subsequent recovery of copper from mnoff mine water as impure cement copper have been practiced since Roman times. Most hydrometaHurgical treatments have been appHed to ores or overburden in which the copper was present as oxide, mixed oxide—sulfide, or native copper. PyrometaHurgical and hydrometaHurgical processes are compared in Reference 34. 

The attraction of rubbed amber and some other effects of electricity were known in ancient times. We know from finding nails in an old wreck that the Romans knew about contact corrosion combined with electric current flow. A skin of lead as a protection against boring worms covered the wooden planks of the ship and was nailed down with copper nails. Galvanic coupIe.s formed between the lead and the copper nails and the less noble lead sheets around the nails corroded in the seawater and fell off. The shipbuilders discovered a simple solution and covered the heads of the copper nails with lead as well. Galvanic current flow between the two metals was eliminated and corrosion was prevented (26). 

The name of a monatomic cation is the same as the name of the element forming it, with the addition of the word ion, as in sodium ion for Na+. When an element can form more than one kind of cation, such as Cu+ and Cu2+ from copper, we use the oxidation number, the charge of the cation, written as a Roman numeral in parentheses following the name of the element. Thus, Cu+ is a copper(I) ion and Cu2+ is a copper(II) ion. Similarly, Fe2+ is an iron(II) ion and Fe3" is an iron(III) ion. As shown in Fig. C.6, most transition metals form more than one kind of ion so unless we are given other information we need to include the oxidation number in the names of their compounds. 

Oxidation state is a frequently used (and indeed misused) concept which apportions charges and electrons within complex molecules and ions. We stress that oxidation state is a formal concept, rather than an accurate statement of the charge distributions within compounds. The oxidation state of a metal is defined as the formal charge which would be placed upon that metal in a purely ionic description. For example, the metals in the gas phase ions Mn + and Cu are assigned oxidation states of +3 and +1 respectively. These are usually denoted by placing the formal oxidation state in Roman numerals in parentheses after the element name the ions Mn- " and Cu+ are examples of manganese(iii) and copper(i). 

The name copper and the symbol Cu are derived from the Latin cuprum, after the island of Cyprus, where the Romans first obtained copper metal. The symbols Ag and Au for silver and gold come from the Latin names for these elements argentum... 

Ancient artisans were able to confer special colourings to their artefacts by applying particular techniques and treatments, which were lost in later centuries. They were also able to give copper based alloys the appearance of precious metals. Some of these special methods have been discovered and identified on ancient objects. The most famous of these alloys in Roman times was certainly Corinthian bronze, a copper alloy containing small amounts of precious metals, which acquired a purple-black or blue-black patination... 

Copper (chemical symbol Cu, from the Latin name of the metal, cuprum), the metal that in Roman times was known as the Cyprian metal (since much of the metal came from Cyprus), is reddish brown, malleable and ductile, and can be easily shaped by cold- or hot-working techniques (see Fig. 35) (Scott 2002). Native copper occurs mainly in the form of boulders, nuggets, dendrites, and laminar outgrowths. It was certainly in its native form that copper was first recognized and used for over five millennia since then, however, the bulk of copper has been derived from copper ores by a variety... 

Chemical and other names Copper Cupric sulfate, blue vitriol, cupric sulfate, Roman vitriol, Salzburg vitriol, blue copperas, copper (II) sulfate)... 

Care we write a formal charge with Arabic numerals, and means that the full charge exists as indicated Cu2+ means a copper atom with fully two electronic charges missing. We write an oxidation number with Roman numerals, and does not relate to any physical loss or gain of electrons it is purely a book-keeping exercise. Mnvn does not mean that a manganese atom has lost seven electrons. 

If we accept a date of around AD 1000 for the commencement of the distillation of zinc on a large scale, then, following the work of Craddock (1978), all earlier brasses should contain less than 28% Zn, as this is the approximate upper limit for the calamine process at around 1000 °C. Above this temperature, the process is more efficient, but it is said that the brass produced melts and the active surface area for the process is thus reduced. By granulating the copper and therefore increasing the surface area, the maximum can be pushed to around 33% Zn, but it is unlikely that this was done in Europe until the 18th Century (see Section 6.4). This model is supported by the analytical data Craddock s work on Roman brass indeed shows an upper limit of about 28% zinc. 

Craddock, P.T. (1978). The composition of the copper alloys used by the Greek, Etruscan and Roman civilizations. 3 The origins and early use of brass. Journal of Archaeological Science 5 1-16. 

Ponting, M. and Segal, I. (1998). Inductively coupled plasma-atomic emission spectroscopy analyses of Roman military copper alloy artefacts from the excavations at Masada, Israel. Archaeometry 40 109-122. 

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