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首页> 外文期刊>Metallurgical and Materials Transactions B >Redox Equilibria of Chromium in Calcium Silicate Base Melts
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Redox Equilibria of Chromium in Calcium Silicate Base Melts

机译：硅酸钙基熔体中铬的氧化还原平衡

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摘要

The oxidation state of chromium has been determined at 1600 °C in CaO-SiO2-CrO x melts with CaO/SiO2 ratios (mass pct) of 0.66, 0.93, and 1.10, and 0.15 to 3.00 pct Cr2O3 (initial). A few experiments were also carried out with CaO-SiO2-Al2O3-CrO x melts at 1430 °C. The slag samples were equilibrated with gas phases of controlled oxygen pressure. Two techniques were applied to determine the oxidation state: thermogravimetry and quenching of the samples with subsequent wet chemical analysis. In the low-oxygen pressure range, the chromium is mainly divalent. In the high-oxygen pressure range, it is trivalent and hexavalent. It was found that the Cr3+/Cr2+ and Cr6+/Cr3+ ratios depend on oxygen pressure at a constant CaO/SiO2 ratio and a constant content of total chromium, according to the ideal law of mass action. According to the respective chemical reactions, these ratios change proportional to $ p_{{{text{O}}_{2} }}{}^{1/4} $ or $ p_{{{text{O}}_{ 2} }}{}^{3/4}, $ respectively. They also increase with increasing basicity. The data are used to compute the fractions of the different ions in the melt. There is a certain range of oxygen pressure in which all three valence states, Cr2+, Cr3+, and Cr6+, coexist. The color of the solidified slag samples is described and is explained with the help of transmission spectra.
机译：已在1600°C的CaO-SiO2 -CrO x 熔体中以0.66、0.93和1.10的CaO / SiO2 比（质量pct）确定了铬的氧化态，并且0.15至3.00 pct Cr2 O3 （初始）。还对在1430°C下的CaO-SiO2 -Al2 O3 -CrO x 熔体进行了一些实验。用控制氧气压力的气相平衡炉渣样品。应用了两种技术来确定氧化态：热重分析和样品猝灭以及随后的湿化学分析。在低氧压力范围内，铬主要为二价。在高氧压力范围内，它是三价和六价的。发现Cr3 + / Cr2 + 和Cr6 + / Cr3 + 的比例取决于氧气压力，CaO / SiO2 比例恒定且总含量恒定铬，根据理想的质量作用定律。根据各自的化学反应，这些比例与$ p _ {{{text {O}} _ {2}}} {} ^ {1/4} $或$ p _ {{{text {O}} __ { 2}}} {} ^ {3/4}，$。它们也随着基本性的提高而增加。数据用于计算熔体中不同离子的分数。在一定的氧气压力范围内，所有三个价态Cr2 + ，Cr3 + 和Cr6 + 共存。描述了固化炉渣样品的颜色，并借助透射光谱对其进行了解释。

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