Solubility diagram for the system KHCO3 + KVO3 + H2O at 293–323 K

The solubility of potassium bicarbonate and potassium meta-vanadate in water in the temperature range 293–323 K is reported. The concentration of vanadium(V) was determined using a spectrophotometric method applying hydrogen peroxide. The potassium ion concentration was measured by weight in the form of potassium tetraphenyloborate (K[B(C6H5)4]). The results were used to construct a part of the polythermal solubility surface for the KHCO3+KVO3+H2O system. In addition, the solution density dependence versus the potassium meta-vanadate concentration expressed in water free mole fractions is presented. These data are essential for the evaluation of a new, non-waste production method of potassium carbonate.