[123], Because silver was extensively used as a decorative material and an exchange medium, lead deposits came to be worked in Asia Minor from 3000 BCE; later, lead deposits were developed in the Aegean and Laurion. [96], In the s-process (s is for "slow"), captures are separated by years or decades, allowing less stable nuclei to undergo beta decay. [100] The r-process does not form as much lead as the s-process. In 2014, 4.58 million metric tons came from primary production and 5.64 million from secondary production. [271] Elevated concentrations of lead persist in soils and sediments in post-industrial and urban areas; industrial emissions, including those arising from coal burning,[272] continue in many parts of the world, particularly in the developing countries. [269] Acute cases may require the use of disodium calcium edetate, the calcium chelate, and the disodium salt of ethylenediaminetetraacetic acid (EDTA). [124] Beginning circa 2000 BCE, the Phoenicians worked deposits in the Iberian peninsula; by 1600 BCE, lead mining existed in Cyprus, Greece, and Sardinia. [206] Because of its corrosion resistance, lead is used as a protective sheath for underwater cables. Gaseous by-product of the coking process, containing. No elements with odd atomic numbers have more than two stable isotopes; even-numbered elements have multiple stable isotopes, with tin (element 50) having the highest number of isotopes of all elements, ten. The neutron flux involved may be on the order of 1022 neutrons per square centimeter per second. That includes the lead alloys. [104], Lead is classified as a chalcophile under the Goldschmidt classification, meaning it is generally found combined with sulfur. In animals, lead exhibits toxicity in many organs, damaging the nervous, renal, reproductive, hematopoietic, and cardiovascular systems after ingestion, inhalation, or skin absorption. The stable form of tin above this temperature is called β- or white tin and has a distorted face centered cubic (tetragonal) structure which can be derived by compressing the tetrahedra of gray tin along their cubic axes. Because of its toxicity, European and North American manufacturers use alternatives such as zinc. Arsenic, tin, antimony, silver, gold, copper, and bismuth are common impurities in lead minerals. [245], Lead is a highly poisonous metal (whether inhaled or swallowed), affecting almost every organ and system in the human body. Wheel Weight – Clip On, (0.5% Tin, 2% Antimony, 97.5% Lead), Pistol, Rifle, Brinell 12, 10.6 Hardness is probably the most poorly defined material property because it may indicate resistance to scratching, resistance to abrasion, resistance to indentation or even resistance to shaping or localized plastic deformation. If you have very soft lead to start with, you need to add one of those hardening alloys. 450-1100)-language text, Articles containing Russian-language text, Articles containing Persian-language text, Wikipedia articles incorporating text from open access publications, Articles with Encyclopædia Britannica links, Creative Commons Attribution-ShareAlike License, This page was last edited on 25 November 2020, at 08:48. Secondary lead production is therefore cheaper, in terms of energy requirements, than is primary production, often by 50% or more.[186]. Controlling Lead Bullet Hardness Pure lead is often described as "dead soft". Magnum Shot, (5% Antimony, 95% Lead), Shotgun, Brinell ?? [109], World lead resources exceed two billion tons. [256] High blood levels are associated with delayed puberty in girls. The earliest record dates to 1621 in the English Colony of Virginia, fourteen years after its foundation. These three regions collectively dominated production of mined lead until c. 1200 BCE. Lead's toxicity has led to its phasing out for some uses. In Roman times, lead sling bullets were amply used, and were effective at a distance of between 100 and 150 meters. [86] Other organolead compounds are less chemically stable. The resulting bismuth dross can be skimmed off. By mimicking calcium, lead can cross the blood–brain barrier. [257] The rise and fall in exposure to airborne lead from the combustion of tetraethyl lead in gasoline during the 20th century has been linked with historical increases and decreases in crime levels, a hypothesis which is not universally accepted. Pliny incorrectly wrote that stibnite would give lead on heating, instead of antimony. [290] Lead abatement programs have been mandated by some authorities in properties where young children live. [171], In the 1970s, the United States and Western European countries introduced legislation to reduce lead air pollution. [248] Cigarette smoke contains, among other toxic substances, radioactive lead-210. [109] Most other lead minerals are related to galena in some way; boulangerite, Pb5Sb4S11, is a mixed sulfide derived from galena; anglesite, PbSO4, is a product of galena oxidation; and cerussite or white lead ore, PbCO3, is a decomposition product of galena. In addition to being the main application for lead metal, lead-acid batteries are also the main consumer of lead compounds. © 2020 Florida Reloading CLasses| All rights reserved | [179] The share of the world's lead production by the Eastern Bloc increased from 10% to 30%, from 1950 to 1990, with the Soviet Union being the world's largest producer during the mid-1970s and the 1980s, and China starting major lead production in the late 20th century. [181] As was the case during European industrialization, lead has had a negative effect on health in China. It is usually found in the ores of silver, zinc, and copper. [97] A stable thallium-203 nucleus can capture a neutron and become thallium-204; this undergoes beta decay to give stable lead-204; on capturing another neutron, it becomes lead-205, which has a half-life of around 15 million years. While there are several lead hardness testers on the market, some of them provide obscure hardness references. [238], Lead has no confirmed biological role, and there is no confirmed safe level of lead exposure. You can approximate the amount of hardener or pure lead needed to get to a proper range. Such additives include clip on wheel weights, linotype, and monotype. [174], The last major human exposure to lead was the addition of tetraethyllead to gasoline as an antiknock agent, a practice that originated in the United States in 1921. [113], There is no consensus on the origin of the Proto-Germanic *lauda-. That’s all very quick (POP! [58] This makes the organometallic chemistry of lead far less wide-ranging than that of tin. [112] The Old English word is derived from the hypothetical reconstructed Proto-Germanic *lauda- ("lead").


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