aluminum

Aluminium (aluminum in American and Canadian English) is a chemical element with the symbol Al and atomic number 13. Aluminium has a density lower than those of other common metals, at approximately one third that of steel. Aluminium has a great affinity [亲和度] towards oxygen, thanks to which it forms a protective layer of oxide on the surface.

Aluminium visually resembles [类似] silver, both in color and in great ability to reflect light. Aluminium is soft, non-magnetic [非磁性] and ductile [有延展性]. It has one stable isotope [同位素], 27Al; this isotope is very common, making aluminium the twelfth most common element in the Universe. The radioactivity [放射性] of 26Al is used in radiodating. All isotopes of a given element [元素] have the same number of protons [质子] but different numbers of neutrons [中子] in each atom.

The discovery of aluminium was announced in 1825 by Danish physicist Hans Christian Ørsted. Aluminium became much more available to the public with the Hall–Héroult process developed independently by French engineer Paul Héroult and American engineer Charles Martin Hall in 1886.

Despite its prevalence [常见] in the environment, no living organism is known to use aluminium salts metabolically [新陈代谢地], but aluminium is well tolerated [耐受] by plants and animals. Because of the abundance of these salts, the potential for a biological role for them is of continuing interest, and studies continue.

In most people, aluminium is not as toxic [有毒] as heavy metals. Aluminium is classified as a non-carcinogen [致癌物] by the United States Department of Health and Human Services. There is little evidence that normal exposure [暴露] to aluminium presents a risk to healthy adult, and there is evidence of no toxicity if it is consumed in amounts not greater than 40 mg/day per kg of body mass [体重]. Most aluminium consumed will leave the body in feces [粪便]; most of the small part of it that enters the bloodstream, will be excreted [排泄] via urine. [尿]

另据http://www.youlai.cn/yyk/article/372579.html: 铝锅对人体有无危害,主要取决于铝锅的使用方式以及使用频率。通常情况下,在蒸煮料理时使用铝锅,基本上对于人体并无危害。但长期使用铝锅可能造成铝元素在体内潴留,当累积到一定程度后,对人体具有一定程度的危害,可能引起机体缺钙、过早衰老、消化功能紊乱、贫血、肝肾损伤等一系列负面影响。

个人认为:铁锅和不锈钢锅也不算贵,能不冒险就不冒险。但也不必谈铝色变。

British chemist Humphry Davy, who performed a number of experiments aimed to isolate [分离] the metal, is credited [归功于] as the person who named the element. The first name proposed for the metal to be isolated from alum [明矾,白矾] was alumium, which Davy suggested in an 1808 article on his electrochemical research.

In 1812, British scientist Thomas Young wrote an anonymous review of Davy's book, in which he proposed the name aluminium instead of aluminum, which he felt had a "less classical [古典的] sound". In 1828, American lexicographer [辞典人] Noah Webster used exclusively [only] the aluminum spelling in his American Dictionary of the English Language. The International Union of Pure and Applied Chemistry (IUPAC) adopted [采用] aluminium as the standard international name for the element in 1990.] In 1993, they recognized aluminum as an acceptable variant [变体].

Aluminium production is highly energy-consuming. China is by far the top producer of aluminium with a world share of fifty-five percent. Recovery of the metal through recycling has become an important task of the aluminium industry. Recycling involves melting [融化] the scrap [碎片], a process that requires only 5% of the energy used to produce aluminium from ore [矿石].

The global production of aluminium in 2016 was 58.8 million metric tons. ton: measure of weight, in Britain 2240 lb(long ton) and in the US 2000 lb (short ton); tonne: metric ton, 1000 kilograms.

Aluminium is almost always alloyed, which markedly improves its mechanical properties, especially when tempered [回火]. For example, the common aluminium foils [箔] and beverage cans [饮料罐] are alloys [合金] of 92% to 99% aluminium.

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