Cr2O3的特点及其在耐火材料中的应用

Cr2O3化学性质稳定，耐酸碱、高温性质稳定，具有很高的硬度和良好的耐火性能。在高温下，Cr3+会被部分地转变为Cr2+，从而使Cr2O3的熔点降低。因此，Cr2O3的熔点还没有统一的意见，只有一个温度范围2265~2330℃。尽管如此，具有如此高的熔点范围，在耐火材料中的应用是足够的。Cr2O3与一些主要的耐火氧化物作用时，形成的化合物熔点较高或是形成的多元系统的低共熔点高，所以是耐火材料的重要原料和添加剂，如表1所示。

表1Cr2O3与一些耐火氧化物形成的二元系统

Cr2O3 has stable chemical properties, acid-base resistance and high temperature properties, with high hardness and good fire resistance.At high temperatures, Cr3+ is partially converted to Cr2+, thus reducing the melting point of Cr2O3.Therefore, there is no unified opinion on the melting point of Cr2O3, with only a temperature range of 2265~2330℃.Nonetheless, with such a high range of melting points, application in refractory is sufficient.When Cr2O3 acts with some major refractory oxides, the formed compounds are high or the low comelting points of the formed multiple systems, so they are important ingredients and additives for refractory materials, as shown in Table 1.

Table 1 Binary system formed by Cr2O3 with some refractory oxides

在冶炼过程中，炉渣通常是以氧化钙(CaO)和二氧化硅(SiO2)为主要成分的多种氧化物的混合物。如将炉渣视为CaO-SiO2二元系统，可与氧化铬(Cr2O3)、三氧化二铝(Al2O3)和氧化镁(MgO)分别构成Cr2O3-CaO-SiO2、Al2O3-CaO-SiO2和MgO-CaO-SiO2三元系，则可通过比较各相平衡状态图分析各种耐火材料的抗渣侵机理。Cr2O3-CaO-SiO2、Al2O3-CaO-SiO2和MgO-CaO-SiO2

During smelting, slag is usually a mixture of multiple oxides with calcium oxide (CaO) and silica (SiO2) as the main components.If slag is regarded as a CaO-SiO2 binary system for Cr2O3-CaO-SiO2, Al2O3-CaO-SiO2 and MgO-CaO-SiO2 triples with chromium oxide (Cr2O3), aluminum trioxide (Al2O3) and magnesium oxide (MgO), respectively, the slag resistance mechanism of various refractory materials can be analyzed by comparing each phase equilibrium state diagram.Cr2O3-CaO-SiO2, Al2O3-CaO-SiO2 and MgO-CaO-SiO2

当Cr2O3、Al2O3和MgO分别与氧化钙和二氧化硅混合，并在不同温度下加热时，Cr2O3、Al2O3和MgO分别与熔渣反应并溶入炉渣中，且在其溶解超过一定量后即达到饱和，上述各氧化物便不再溶解。Cr2O3、Al2O3和MgO在各三元系内的溶解量，随碱度(R)和温度的变化而变化。

When Cr2O3, Al2O3 and MgO are mixed with calcium oxide and silica, respectively, and heated at different temperatures, Cr2O3, Al2O3 and MgO react with the slag and dissolve into the slag, and reach saturation after its dissolution exceeds a certain amount, the above oxides are no longer dissolved.The amount of Cr2O3, Al2O3 and MgO dissolution within each triplet, varies with alkalinity (R) and temperature.

R=1.0、0.6的炉渣其氧化铬的溶解量最少，氧化镁次之，Al2O3最多。与Al2O3相比，Cr2O3在渣中只要达1/3～1/10即可使炉渣达到饱和状态，亦即只要极少量的Cr2O3参与炉渣反应，炉渣就可达到饱和，Cr2O3也不再与炉渣反应。因此，Cr2O3在耐火材料中能够起到很好的抗侵蚀性能。

The slag of R=1.0 and 0.6 dissolved the least chromium oxide, followed by magnesium oxide and the most Al2O3.Compared with Al2O3, Cr2O3 can saturated the slag by 1 / 3~1 / 10 in the slag, i. e., if very few Cr2O3 participates in the slag reaction, the slag can be saturated and the Cr2O3 no longer reacts with the slag.Therefore, Cr2O3 has a good erosion resistance in refractory materials.