Formation of minor phases was observed during production of ZrB2 by VCS. Ignition under argon atmosphere prevented the formation of minority phase Zr2ON2 but formation of Mg3B2O6 could not be prevented. Elimination of Mg3B2O6 from the reaction product could be achieved by first wet ball milling the product for 7 h in ethanol and then leaching in 5 M HCl solution for 2.5 h. Complete reduction of ZrO2 could not be achieved most probably because of the stability of ZrO2.