Factor analysis on the purity of magnesium titanate directly prepared from seashore titanomagnetite concentrate through
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Factor analysis on the purity of magnesium titanate directly prepared from seashore titanomagnetite concentrate through direct reduction Xiao-ping Wang 1), Zhao-chun Li 2), Ti-chang Sun 3), Jue Kou 3), and Xiao-hui Li 3) 1) School of Mining and Coal, Inner Mongolia University of Science and Technology, Baotou 014010, China 2) China Sinda Intellectual Property Limited, Beijing 100033, China 3) School of Civil and Resource Engineering, University of Science and Technology Beijing, Beijing 100083, China (Received: 29 September 2019; revised: 21 January 2020; accepted: 22 January 2020)
Abstract: Magnesium titanate was prepared directly through external coal reduction of seashore titanomagnetite concentrate and magnesium oxide (MgO). The effects of roasting temperature and the type and dosage of reductants on the purity of generated magnesium titanate particles were systematically investigated. Scanning electron microscopy and energy-dispersive spectroscopy analyses were performed to characterize the magnesium titanate particles and observe their purity under different conditions. Results showed that the roasting temperature remarkably influenced the purity of magnesium titanate. At 1200, 1300, and 1400°C, some magnesium ferrite and magnesium aluminate spinel were dissolved in magnesium titanate. However, as the roasting temperature increased to 1500°C, relatively pure magnesium titanate particles were generated because no magnesium ferrite was dissolved in them. The type and dosage of the reductants also remarkably affected the purity of magnesium titanate. The amount of fine metallic iron disseminated in the magnesium titanate particles obviously decreased when lignite was used as a reductant at a dosage of 70wt%. Thus, high-purity magnesium titanate particles formed. At a roasting temperature of 1500°C and with 70wt% lignite, the magnesium titanate product with a yield of 30.63% and an iron content of 3.01wt% was obtained through magnetic separation. Keywords: seashore titanomagnetite; magnesium oxide; direct reduction; magnesium titanate
1. Introduction As a raw material used for preparing microwave dielectric ceramic materials, magnesium titanate has many industrial applications, such as high-frequency capacitors, temperaturecompensating capacitors, and chip capacitors [1‒2]. It is produced mainly through industrial preparation methods, including solid-phase reaction, chemical precipitation, electrochemical method, and polymer decomposition [3‒4]. However, these conventional methods have high requirements on raw materials and complex processes, resulting in costly magnesium titanate preparation. Seashore titanomagnetite (TTM) is abundantly found in reserves and detected in mining [5‒6]. It contains 5wt%–10wt% TiO2. TiO2 may be separated into an iron concentrate through conventional concentration methods, but this phenomenon exacerbates difficulties in ironmaking and prevents the effective recycling of titanium resources [7]. Reduction followed by magnetic separation has b
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