Abstract Titanium dioxide is an important material with a wide range of applications. Different methods and processes have been introduced and applied to produce pure TiO2 from available titanium ores and mineral sources. This paper describes the production of nano-sized titanium dioxide (TiO2) from ilmenite concentrate provided by the main Iranian Ilmenite processing complex. Ilmenite (FeTiO3) concentrate was decomposed using (70% wt.) potassium hydroxide solution at 220 °C and under air at atmospheric conditions. The decomposed product was leached using hydrochloric acid solution, and Ethylenediaminetetraacetic acid (EDTA) was applied for chelating and separating iron impurity from the leach solution. Ammonia solution was used for precipitation, and the anatase TiO2 nanoparticles were produced in the following filtration, drying, and calcination processes. The water content of the filtrate solution was evaporated, and it was dried to produce a powdery product. The crystal phases of ilmenite, decomposed ilmenite, and the TiO2 product were characterized by X-ray diffraction (XRD), and the chemical compositions of the ilmenite concentrate, products, and the filtrate were determined using inductively coupled plasma-optical emission spectrometry (ICP-OES). The morphological study of the decomposed ilmenite and synthesized-TiO2 was performed using scanning electron microscope (SEM) and field emission scanning electron microscope (FESEM), respectively. The particle size measurement of the TiO2 product was conducted using dynamic light scattering (DLS) method. The crystal system and lattice parameters were calculated by the Rietveld refinement method. The purity of the produced synthesized-TiO2 was determined to be more than 90% with a mean particle size diameter of around 70 nm. The filtrate solution (as the main byproduct of the process) contained Fe-EDTA chelated complexes, sodium, potassium, and some other constituents that can be used in agricultural fertilizer production.

中文翻译：

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钛铁矿浸出及制备TiO2纳米颗粒的改进工艺

摘要 二氧化钛是一种应用广泛的重要材料。已经引入并应用了不同的方法和工艺，以从可用的钛矿石和矿物来源生产纯 TiO2。本文介绍了从伊朗主要钛铁矿加工厂提供的钛铁矿精矿生产纳米级二氧化钛 (TiO2) 的过程。钛铁矿 (FeTiO3) 浓缩物在 220 °C 和空气中使用（70% wt.）氢氧化钾溶液在大气条件下分解。分解产物用盐酸溶液浸出，乙二胺四乙酸(EDTA)用于螯合分离浸出液中的铁杂质。用氨溶液沉淀，经过滤、干燥、和煅烧过程。蒸发滤液中的水分，干燥得到粉状产品。钛铁矿、分解钛铁矿和 TiO2 产物的晶相通过 X 射线衍射 (XRD) 表征，钛铁矿精矿、产物和滤液的化学成分通过电感耦合等离子体发射光谱法 (ICP) 确定-OES）。分别使用扫描电子显微镜 (SEM) 和场发射扫描电子显微镜 (FESEM) 对分解的钛铁矿和合成的 TiO2 进行形态研究。使用动态光散射 (DLS) 方法进行 TiO2 产品的粒度测量。晶系和晶格参数通过Rietveld精修方法计算。所生产的合成 TiO2 的纯度被确定为超过 90%，平均粒径约为 70 nm。滤液（作为该过程的主要副产品）含有 Fe-EDTA 螯合物、钠、钾和一些其他可用于农业肥料生产的成分。