A novel low‐energy approach to leucoxene concentrate desiliconization by ammonium bifluoride solutions

Abstract

BACKGROUND: Despite the large reserves of titanium ores, their treatment by basic approaches to obtain titanium products is not always economically feasible due to various factors. One of these problems is the high content of silicon in the ores. RESULTS:The paper considers the desiliconization of a leucoxene concentrate with an aqueous solution of ammonium bifluoride. It was found that at 80 °C the main impurities, such as silicon and iron, pass into solution in the form of corresponding ammonium-fluorine complex compounds.CONCLUSIONS: The degree of desiliconization was up to 99%. Aluminium reacts with ammonium bifluoride, but is almost not leached into solution due to its low solubility. Titanium does not react due to its relatively higher reaction Gibbs energy among other metals in reaction with ammonium bifluoride. The content of titanium oxide in the calcined leaching residue was 85.52 wt%. The resulting residue corresponds to the raw material used in industry for the production of titanium dioxide pigment or titanium metal by the chlorine method. Iron and silicon can be precipitated from the leaching solution. Furthermore, the resulting filtrate can be evaporated in order to regenerate and reuse ammonium bifluoride.

High-strength gypsum binder with improved water-resistance coefficient derived from industrial wastes

“…Waste recycling is one of the main components of sustainable development, green chemistry (Stahel, 2016;Nelles et al, 2016), and the circular economy (Pires and Martinho, 2019;van Ewijkand Stegemann, 2020). Known examples of the involvement of waste in the production complex are the production of pigments (Zalyhina et al, 2021a;b), materials for water and wastewater treatment (Romanovski et al, 2021a;Romanovskii and Martsul', 2009;Bakhsh et al, 2022), building materials such as gypsum (Kamarou et al, 2020;, binders (Kamarou et al, 2021b;2021c;Romanovski et al, 2021b), building blocks (Akinwande et al, 2022a;2022b;Ademati et al, 2022), composite materials (Akinwande et al, 2022c;Ogunsanya et al, 2022), as well as the modi cation of known methods through the use of waste, which can reduce energy costs for production (Smorokov et al, 2022;2023a;2023b). Materials obtained on the basis of gypsum binders are promising materials due to their operational properties, as well as low energy costs for their production.…”

Study on the Fluorination Process of Sc2O3 by NH4HF2

“…At room temperature, NH 4 HF 2 does not represent any significant environmental danger, since it is solid with a very low partial pressure, whereas, when heated, it becomes a powerful fluorinating reagent [16,17]. Therefore, NH 4 HF 2 is widely used to purify minerals and prepare fluorides from rare-earth oxides, for example, silica concentrate desilication [18], metal slag desiliconization [19], desilication of zirconium concentrates [20] and the production of GdF 3 [21], PuF 3 [22], and YF 3 [23].…”