The phosphate adsorption process from the wastewater is a promising way to produce fertilizers and gain phosphorus for the chemical industry. To improve the efficiency of this process a multi-scale investigation is necessary. Macro-scale simulation models are well applicable to complete reactors and can be used for the optimization or recovery of unknown parameters [1, 2]. Disadvantageously, it requires the predefined mathematical approach describing the adsorption mechanism. Most data available for phosphate adsorption processs contain experimentally fitted Langmuir adsorption isotherms, which do not consider many important parameters such as pore size, changing pore geometry, surface electric potential, ionic electrical forces and surface reaction rates. In contrast to macro-scale modeling, the meso-scale characteristics of lattice Boltzmann methods allow to investigate the nano-pores of the adsorbent micro-particles and enable the consideration of phosphate recovery not as adsorption but as crystallization reaction with crystal products. In the current work, a novel electrochemical model is introduced that describes the dynamics of the solved phosphate ions as well as the dissolution of the calcium ions from the pore surface and their reaction to crystal. The latter consists of nucleation and crystal growth which allows tracking of the crystal dimensions and updating the pore geometry for the hydrodynamics simulation. Our novel mesoscopic simulation approach can be used for example to derive a new parameterized adsorption model for the process optimization on the macroscopic level.