Occurrences, uses, and properties of chromium
Occurrences, uses, and properties of chromium
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DOI：
10.1006/rtph.1997.1132
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发表时间：
1997-08-01
影响因子：
3.4
通讯作者：
Barnhart, J
中科院分区：
文献类型：
--
作者：
Barnhart, J
铬是地壳中第21种最丰富的元素，在美国土壤中的平均浓度约为40毫克/公斤。虽然它以几种氧化态存在，但零、三价和六价态在商业产品和环境中是最重要的。几乎所有自然产生的铬都处于三价状态，通常与铁或其他金属氧化物结合。虽然只有15%的铬被用于制造化学品，但大多数铬的应用都是利用铬的化学作用。例如，不锈钢的“不锈钢”性质是由于在合金表面形成的铬氧化物的化学性质。同样，金属的镀铬、木材的铬化砷酸铜(CCA)处理以及皮革的铬鞣处理的保护性能都依赖于铬的化学成分。这些用途的关键是，在pH值和氧化还原电位的典型环境和生物条件下，铬最稳定的形式是三价氧化物。这种形式具有很低的溶解度和低反应性，导致在环境中的流动性低，在生物体内的毒性低。本文以铬的Eh-pH图为基础，讨论了主要工业产品中铬的化学性质。(C)1997年学术出版社。
Chromium is the 21st most abundant element in the Earth's crust with a mean concentration in United States soils of about 40 mg/kg. Although it exists in several oxidation states, the zero, trivalent, and hexavalent states are the most important in commercial products and the environment. Nearly all naturally occurring chromium is in the trivalent state, usually in combination with iron or other metal oxides. Although only about 15% of the chromium mined is used in the manufacture of chemicals, most applications of chromium utilize the chemistry of chromium. For instance, the ''stainless'' nature of stainless steel is due to the chemical properties of the chromium oxides which form on the surface of the alloy. Similarly, the protective properties of chrome plating of metals, chromated copper arsenate (CCA) treatment of wood, and chrome tanning of leather are all dependent on chromium chemistry. The key to these uses is that under typical environmental and biological conditions of pH and oxidation-reduction potential, the most stable form of chromium is the trivalent oxide. This form has very low solubility and low reactivity resulting in low mobility in the environment and low toxicity in living organisms. In this paper the chemical properties of chromium are discussed for the major commercial products in the context of the Eh-pH diagram for chromium. (C) 1997 Academic Press.