2020 年 76 巻 7 号 p. III_181-III_187
This paper reports the recovery of phosphorus and potassium from biomass aiming at removing accumulated nutrients in soil in agriculture and to reuse them. At first, the thermodynamic properties were determined for precipitate which contains phosphorus and potassium together in pure chemical solution. The precipitate formed had K:Mg:P ratio of 1:1:1, but different crystalline structure from struvite-K reported so far. The solubility product, ΔrG°, ΔrH° of dissolution reaction of the precipitate were 10−10.9, −62.4 and −23.0 kJ/mol, respectively. Then, a method to recover P and K from biomass was proposed. The experiment demonstrated that those elements were recovered when KCl solution was used as the initial extraction solvent.
