The work is devoted to developing a cost-efficient method for the processing of metallurgical wastes such as oiled mill scale formed upon the mechanical cleaning of a hot-rolled steel strip in scalebreakers. The most significant parameters of a chemical-metallurgical process for producing expensive and highly marketed products, such as α-Fe2O3 and γ-Fe2O3 nanopowders, are experimentally determined. The properties of initial materials and nanodispersed products have been studied by X-ray diffractometry, energy dispersive spectroscopy, scanning and transmission electron microscopy, and Mössbauer spectrometry. The temperature and field dependences for the powder magnetization have been plotted according to the measurements performed with the use of a vibration magnetometer. The mill scale under investigation consists of three main phases: wustite, magnetite and hematite at a weight ratio of 6 : 8 : 7, respectively. The initial scale was activated in a magnetic mill in a hydrogen flow and dissolved in a mixture of hydrochloric and nitric acids. The resulting solutions have been used to obtain α-Fe2O3 nanocrystalline hematite by a chemical-metallurgical method, the main stages of which consist in hydroxide precipitation with the use of alkali at constant pH, washing, drying, and dehydration. Maghemite γ-Fe2O3 has been obtained from hematite in two stages. At the first stage, hydrogen reduction has been performed, whereas at the second stage, the obtained magnetite has been oxidized in air. The particles of synthesized nanodispersed oxide powders are in the aggregated condition. The particles of α-Fe2O3 are spherical, whereas the particles of γ-Fe2O3 are rod-shaped. According to Mössbauer spectroscopy, the lattices of both oxides contain magnesium, aluminum, silicon, chromium, and manganese that originate from the initial scale. These elements determine magnetic properties of α-Fe2O3 and γ-Fe2O3 nanopowders. The set of properties inherent in nanodispersed hematite and maghemite powders obtained from metallurgical wastes (mill scale) is recommended for the application in catalytic processes, in the systems of industrial wastewater purification from heavy metal ions, as well as in the manufacturing of blood analysis markers.

中文翻译：

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轧机氧化皮制备的赤铁矿和磁赤铁矿纳米粉的结构、形貌和磁性

这项工作致力于开发一种具有成本效益的方法来处理冶金废物，例如在去鳞机中对热轧钢带进行机械清洁时形成的油氧化皮。用于生产昂贵且高度市场化的产品（例如 α-Fe2O3 和 γ-Fe2O3 纳米粉末）的化学冶金工艺的最重要参数是通过实验确定的。已通过 X 射线衍射、能量色散光谱、扫描和透射电子显微镜以及穆斯堡尔光谱研究了初始材料和纳米分散产品的性质。根据使用振动磁强计进行的测量绘制了粉末磁化的温度和场依赖性。被调查的氧化皮包括三个主要阶段：方氏体、磁铁矿和赤铁矿的重量比分别为 6:8:7。最初的氧化皮在磁力研磨机中在氢气流中活化并溶解在盐酸和硝酸的混合物中。所得溶液已用于通过化学冶金方法获得 α-Fe2O3 纳米晶赤铁矿，其主要阶段包括在恒定 pH 值下使用碱进行氢氧化物沉淀、洗涤、干燥和脱水。磁赤铁矿γ-Fe2O3 已从赤铁矿中分两个阶段获得。在第一阶段进行氢还原，而在第二阶段，所得磁铁矿已在空气中氧化。合成的纳米分散氧化物粉末的颗粒处于聚集状态。α-Fe2O3 的颗粒是球形的，而 γ-Fe2O3 的颗粒是棒状的。根据穆斯堡尔光谱，两种氧化物的晶格都包含源自初始尺度的镁、铝、硅、铬和锰。这些元素决定了 α-Fe2O3 和 γ-Fe2O3 纳米粉末的磁性。从冶金废物（轧制规模）中获得的纳米分散赤铁矿和磁赤铁矿粉末所固有的一组特性被推荐用于催化过程、工业废水净化系统中的重金属离子以及血液分析标记物的制造.