Determining the free lime (f-CaO) content in steelmaking slag is critical for road construction because f-CaO is likely to cause road expansion. Herein, we present a method to determine an area fraction of f-CaO from fractions of illuminated areas related to f-CaO in cathodoluminescence (CL) or X-ray excited optical luminescence (XEOL) image of industrial steelmaking slag, which is simpler and quicker than the commonly employed ethylene glycol extraction method. A heat-treatment in which the industrial steelmaking slag was quenched from 1000 °C was needed to obtain intense luminescence from f-CaO, which originated from a peak at 600 nm. Other mineral phases, such as Ca2SiO4, free magnesia, and 2CaO·Al2O3·SiO2, were distinguishable from f-CaO from their luminescent colors. When we analyzed three types of industrial steelmaking slag with different f-CaO contents, the order of the fractions of the illuminated areas originating from f-CaO in the CL images was consistent with that of the f-CaO content measured applying the ethylene glycol extraction method. The average exposure times it took the CL and XEOL images to detect the luminescence from f-CaO were 5 and 30 seconds, respectively. In particular, acquiring XEOL images is promising for on-site analysis.

中文翻译：

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用阴极发光和 X 射线激发光致发光测定炼钢渣中游离石灰的面积分数

确定炼钢炉渣中游离石灰 (f-CaO) 的含量对于道路建设至关重要，因为 f-CaO 可能会导致道路膨胀。在此，我们提出了一种从工业炼钢渣的阴极发光 (CL) 或 X 射线激发光学发光 (XEOL) 图像中与 f-CaO 相关的照明区域的分数确定 f-CaO 的面积分数的方法，该方法更简单、更准确。比常用的乙二醇提取方法更快。需要将工业炼钢炉渣从 1000 °C 淬火热处理，以获得源自 600 nm 峰的 f-CaO 的强烈发光。其他矿物相，如 Ca2SiO4、游离氧化镁和 2CaO·Al2O3·SiO2，从它们的发光颜色可以与 f-CaO 区分开来。当我们分析具有不同 f-CaO 含量的三种工业炼钢渣时，CL 图像中源自 f-CaO 的照明区域的分数顺序与应用乙二醇提取测量的 f-CaO 含量的顺序一致方法。CL 和 XEOL 图像检测 f-CaO 发光的平均曝光时间分别为 5 秒和 30 秒。特别是，获取 XEOL 图像很有希望用于现场分析。