Autoclave breakdown of zircon with ammonium fluorides

Investigation of Zr(IV) in LiF–CaF2: Stability with oxide ions and electroreduction pathway on inert and reactive electrodes

“…ZrF 4 is mainly prepared by chemical reaction between zirconium oxide ZrO 2 and a fluorinating agent, such as fluorine gas [12], hydrogen fluoride [13], ammonium bifluoride [14] or bromium trifluoride [15]. These syntheses evidence the existence of a great number of zirconium oxifluorides solid phases.…”

Hydrofluoride decomposition of natural materials including zirconium-containing minerals

“…Sublimation properties of (NH 4 ) 2 SiF 6 were used for separation of zirconium and silicon from Tugan zircon deposit of Tomsk region (Russia) [8]. We performed the trace elements analysis of precious opals of deposit Raduzhnoe (Primorsky region, Russia) with respect to the problem of their coloring using sublimation of (NH 4 ) 2 SiF 6 [15].…”

“…Tantalite dissolution using NH 4 HF 2 as alternative to HF [6] or processing of tantalite ore from Mozambique with molten NH 4 HF 2 [7] were also described. For decomposition of refractory zircon, an autoclave breakdown with ammonium fluorides [8] or microwave digestion with NH 4 HF 2 were studied [9,10]. Today, the NH 4 HF 2 acid digestion is recognized as a new method in analytical chemistry which is practical and effective and has lower toxicity and cost, compared with traditional hydrofluoric acid digestion [11][12][13].…”