A method for synthesis of magnesium oxide by calcination of magnesium carbonate, obtained by carbonisation of magnesium hydroxide with carbon dioxide, is presented and the products obtained are characterised. The influence of the following experimental conditions on the final product properties was established: pH of the reaction medium, mode and rate of reagents supply. The final products were characterised by determination of their dispersion properties, wettability profiles (with water), specific surface area (BET), size and volume of pores. The products were identified by the X-ray diffraction method. The results proved a significant influence of the reaction conditions on the physicochemical parameters of the final magnesium oxide.