This research focused on investigating the properties and phase transition of ilmenite ore with various carbon reductants by performing a carbothermal reduction, followed by a hydrogen reduction (Ar:H₂) at 900–1000 °C to extract rutile from the ore. To comprehend the impact of the carbon structure and characteristics on the reduction performance and incorporate a thermodynamic assessment during reduction reactions, two distinct carbon reductants: graphite (GI) and renewable carbon from palm char (PI), were selected. The phase transitions and reduced samples were examined using both qualitative and quantitative X-ray diffraction. The results revealed that ilmenite ore transformed into pseudobrookite ferrous (FeTi₂O₅), titanium trioxide (Ti₃O₅), rutile (TiO₂), and iron (Fe) after carbothermal reduction at 1550 °C where brookite (TiO₂) and anatase (TiO₂) peaks were diminished. As the temperature rose during the secondary reduction by hydrogen, the reduction reaction sequenced as follows: FeTi₂O₅ → Ti₃O₅ → Ti₂O₃ → TiO₂ and Fe. Due to the carbon structure and superior characteristics, the reduced PI demonstrated a greater degree of TiO₂ reduction (81.8%) than the reduced GI (74.8%) at the highest reduction temperature of 1000 °C. In the early and middle stages of the reaction at high temperatures, the carbothermal reduction of ilmenite ore with solid carbon and CO participated and produced rutile, iron, and Ti₃O₅, whereas, in the latter stages, rutile, iron, and Ti₂O₃ are mostly formed when reduced by hydrogen. In conclusion, employing palm char with hydrogen atmosphere to extract pure rutile from ilmenite ore might be accomplished by using these proposed methods.

Graphical Abstract

中文翻译：

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氢气氛下不同碳还原剂碳热还原钛铁矿的结构表征和相变

本研究的重点是通过进行碳热还原，然后在 900–1000 °C 下进行氢还原 (Ar:H 2 ₎以从矿石中提取金红石，研究使用各种碳还原剂的钛铁矿矿石的性质和相变。为了了解碳结构和特性对还原性能的影响，并在还原反应过程中纳入热力学评估，选择了两种不同的碳还原剂：石墨（GI）和来自棕榈焦的可再生碳（PI）。使用定性和定量 X 射线衍射检查相变和还原样品。结果表明，钛铁矿矿石在1550℃碳热还原后转化为铁板钛矿（FeTi ₂ O ₅）、三氧化钛（Ti ₃ O ₅）、金红石（TiO _{2 ）和铁（Fe），其中板钛矿（TiO 2}）锐钛矿(TiO ₂ )峰减少。随着氢二次还原过程中温度升高，还原反应顺序如下：FeTi ₂ O ₅  → Ti ₃ O ₅  → Ti ₂ O ₃  → TiO ₂和Fe。由于碳结构和优异的特性，在最高还原温度1000℃下，还原的PI比还原的GI（74.8％）表现出更大程度的TiO _{2还原（81.8％）。}在高温反应的前、中期阶段，钛铁矿与固体碳和CO参与碳热还原，生成金红石、铁和Ti ₃ O ₅，而在反应后期，则生成金红石、铁和Ti。₂ O ₃主要在被氢还原时形成。总之，使用这些提出的方法可以实现在氢气氛下使用棕榈焦从钛铁矿矿石中提取纯金红石。

图形概要