The work comprises researches on studying the possibility to use Fluoro-Anhydrite - fluor-hydric acid production waste in building industry. The effect of the dispersion and the amount of the neutralising agent on the completeness of the neutralisation reaction of acid Fluoro-Anhydrite is investigated. A method for obtaining a synthanite from hydrofluoric acid production waste is proposed, including neutralisation of the waste with a lime-containing component, followed by grinding and separation of the binder, characterized in that the production waste is additionally denaturalised by its chemical activation with quicklime to pH 12 and a sulfate additive, followed by grinding to a specific surface area of 9,000 cm2/g. Ensuring that the pH level of the binder mixture reaches 10-12 leads to an improvement in the physical and technical properties of synthanite: an increase in strength by 3.5-4 times, a reduction in the setting time by up to 9-12 times. The possibility has been proved to produce ?25 and ?50 dry plasters intended for finishing work based on developed air-hardening synthanite. It is recommended to use plasters inside the premises when air humidity is not higher than (60-70) %.