Bronze containing lead

Molding - Nonferrous alloy castings, such as brass and bronze, contain lead that may generate wastes which are classified as characteristic hazardous waste due to EP Toxicity. 

The earliest of these, a chisel-shaped tool of about 3500 B. C., was of pure copper (99.9 per cent). So also a small figure of about 1300 B. C. was of pure copper. Some fifteen other articles, dating from 1900 B. C. to 350 B. C., were of copper alloyed with tin, ranging from 3 to 14 per cent tin, or with tin and lead, the lead ranging from small quantities, probably unintentional, up to 25 per cent. One figure, of 700 B. C., was of copper with 1.72 per cent arsenic. All of these bronzes contained small quantities of iron, and often small quantities of nickel, cobalt and arsenic, probably unintentional constituents. 

Alloys. Tin is widely used as both a major and minor ingredient of alloy metals. These applications are summarized in Tables 1, 2, and 3. Phosphor bronzes (Table 3) actually contain very little phosphorus, ranging from 0.03 to 0.50%, and hence the alloys are poorly designated. Tin bronzes is the better term. High-silicon bronzes contain about 2.8% tin low-silicon bronzes about 2.0% tin. Gun metals are tin bronze casting alloys with a 5 10% zinc content. Some wrought copper-base alloys contain tin (1) Inhibited Admiralty metal, 1% fin (2) manganese bronze, 1% tin (3) naval brass, 0.75% tin, (4) leaded naval brass, 0.75% tin. See also Copper. 

Dealuminification occurs in aluminum bronzes containing the y-2 phase microstructure and the process is more severe when the y-2 phase forms a continuous grain boundary network. Dealuminification can be averted by rapid cooling from >600°C, or by addition of 1-2% iron or more than 4.5% nickel. Microstmctural changes can still occur during welding and lead to corrosion in the heat-affected zone. 

Pure metals contain metallic bonds, as do alloys. An alloy is a homogeneous mixture of two or more metals. Different alloys can have different amounts of elements. Each alloy, however, has a uniform composition throughout. One example of an alloy is bronze. Bronze contains copper, tin, and lead, joined together with metallic bonds. You will learn more about alloys in Chapter 4 and Chapter 8. 

The application of lead isotope analyses to provenancing almost pure copper artifacts seems relatively straightforward in most instances, but what of arsenical copper and tin bronze alloys In principle, the arsenic in arsenical copper may have been derived from high-arsenic minerals (such as tennantite or basic copper arsenates) containing lead of a different isotopic composition from that of the copper ore used to produce the copper. However, absolutely no archaeological or other evidence of proves that this was ever done in the Bronze Age Aegean. On the contrary, at Kythnos definite evidence shows that arsenical copper was produced in EBII times from arsenical copper ores of variable (sometimes zero) arsenic content but of uniform lead isotope composition. 

Tin bronze is another matter because, apart from rare copper ore deposits also containing tin (e.g., some of those in Cornwall), tin from a quite different source than the copper has almost always been added to copper to produce bronze. The only tin mineral that is likely to contain lead is stannite, which is not common except as a mineralogical curiosity. Tin has always been obtained in very large quantities from cassiterite, which almost never contains even a trace of lead. The tin ingots found underwater off the coast of Israel contain no lead. Our work on Cypriot Late Bronze Age bronzes indicates no perturbation away from the characteristic Cypriot lead isotope composition, even for bronzes containing 18% tin. 

Lead-lined pots were used extensively in cooking, as they prevented the bitterness caused by using bronze containers, imparting a sweet flavour to food. Wine was also prepared in lead-lined containers, specifically because of this sweetening property. The ability of lead to inhibit enzyme activity was well appreciated, and sapa, or grape syrup boiled in leaden vessels, was used extensively as a preservative for fruit and wine. Both Cato (De re rustica, cv) and Pliny (Historia naturalis, xiv, 21 translation of Jones and Rackham, 1938-1963) advocated the treatment of wine in leaden vessels. These practices caused considerable contamination of food and drink, and Gilfallen (1966) has proposed the doubtless excessive idea that the fall of Rome was due to endemic lead poisoning. 

Direct Tooling Mold inserts, which may also contain internal cooling channels, are made with 3D printing processes. The bronze infiltration leads to a higher thermal conductivity, which may be advantageous if the tendency to worse mechanical-technological properties is accepted. 

Bronzes. Tin bronzes can contain between 1 and 10% tin. Phosphor bronze contains up to 0.4% phosphorus. Gunmetal is essentially a tin bronze with up to 5% zinc and may additionally have up to 5% lead. 

Some tin bronzes contain small amounts of lead. In this group of alloys, lead s main function is to improve machinability. It is not present in sufficient concentration to change the alloys bearing properties appreciably. A few of the leaded bronzes also contain zinc, which strengthens the alloys at a lower cost than tin. The leaded bronzes in this family otherwise have properties and application that are similar to the tin bronzes. 

Human bones from the Bronze Age found to contain lead. 

The metals most commonly used for water systems are iron and steel. These metals often have some sort of applied protective coating galvanised steel, for example, relies on a thin layer of zinc, which is anodic to the steel except at high temperatures. Many systems, however, contain a wide variety of other metals and the effect of various water constituents on these must be considered. The more usual are copper, brasses, bronzes, lead, aluminium, stainless steel and solder. 

Tin-bronzes and gunmetals Alloys containing 3-0-12-5% Sn and 0-02-0-04% P, known as phosphor-bronzes, are widely employed. Cast as well as wrought alloys are used, and cast leaded bronzes are also available. 

In former times, tin was used widely as a constituent of metal alloys, of which bronze, solder, and pewter are common examples. Bronze is an alloy of copper containing approximately 20% tin and smaller amounts of zinc. Pewter is another Cu-Sn alloy that contains tin as the major component ( 85%), with roughly equal portions of copper, bismuth, and antimony. Solder consists of 67% lead and 33% tin. 

Electroplating. Typical wastes produced include spent process solutions containing copper, nickel, chromium, brass, bronze, zinc, tin, lead, cadmium, iron, aluminum, and compounds formed from these metals. 

The domestic use pattern for lead in 1990 was as follows lead-acid storage batteries, used for motor vehicles, motive power, and emergency back-up power, accounted for 80% of total lead consumption ammunition, bearing metals, brass and bronze, cable covering, extruded products, sheet lead, and solder, represented 12.4% the remaining 7.6% was used for ceramics, type metal, ballast or weights, tubes or containers, oxides, and gasoline additives (USDOC 1992). 

Silver items, however, are also relatively rare in the archaeological record. The most common metal found is either copper, usually alloyed with either tin (bronze) or, in the later periods, zinc (brass), or iron. The latter contains very little lead and, because of severe corrosion problems, its survival rate is often low (but see Degryse et al., 2007). Fortunately, copper can also be characterized from its lead isotope signature, since the primary ore of copper is chalcopyrite (CuFeS2), which often co-occurs with galena (PbS) and sphalerite (ZnS). Even if the ore used is a secondary mineral formed by the oxidation of the primary deposit, the copper smelted from such a deposit would normally be expected to... 

Hydrofluoric acid must not be stored in glass or silicate ceramic containers. Stainless steel or PTFE are satisfactory for storage and handling. Nonferrous materials such as carbon, bronze, Monel or lead may be used for weaker acids. 

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