**4. Conclusion**

The optimum conditions of natural quartz processing were determined. Sublimation purification of (NH4)2SiF6 is carried out at temperatures from 280 to 380°C and desublimation at 110–120°C. Synthetic silicon oxide with basic substance SiO2 content of 99.999% was obtained.

Technological scheme for fluoroammonium processing of zirconium and obtaining zirconium dioxide is developed. Zircon is completely decomposed by ammonium hydrodifluoride at temperature 400°C and pressure 40 atm in an autoclave.

The technological scheme of ilmenite concentrate processing by ammonium fluoride to pigmented titanium dioxide and iron oxide (III) is developed. The optimal technological modes of ilmenite fluorination at 150–200°C for 2 hours are determined.

The methods for fluoroammonium processing of fluorite-phenakite concentrate and production of beryllium oxide, silicon oxide, and calcium fluoride were proposed. Fluorination occurs at 200°C, purification from silicon at 300–350°C.

We experimentally proved the feasibility of fluoroammonium processing of quartz, zircon, ilmenite, and phenakite minerals. The next step of our research we can propose the adaptation of fluoroammonium technologies for implementation in production.
