Pollution and climate change issues are calling for advanced techniques of pollutant sequestration to decrease toxicity, of coral and costal remediation, and of carbon sequestration to decrease atmospheric CO₂ levels. For that, calcareous deposition appears as an overlooked, but potentially efficient technique. The calcareous deposit is a well-known precipitation by-product of cathodic protection in seawater. The deposit is made of a mixture of CaCO₃ and Mg(OH)₂. A calcareous deposit is formed electrochemically when a metal connected to an electrical power source is immersed in seawater. So far, electrochemical calcareous deposition has seldomly found applications, except for speedup of coral growth, prevention of shore erosion, reinforcement of artificial marine structures and remediation of polluted seawater. Here, we review the principles and mechanisms of electrochemical calcareous deposition. The growth, composition and mechanical properties of calcareous deposits are controlled by several factors such as 1) the impact of electrochemical parameters on the Ca/Mg ratio. For instance, CaCO₃ formation is favoured at low cathodic potentials and low currents, whereas Mg(OH)₂ precipitates preferentially at high cathodic potentials and high applied current; 2) the nature of the metallic electrode: although lime could be deposited onto any metallic surface at a fixed potential, electrochemical reactions and deposit composition are controlled by the metal nature. Moreover, the state of the electrode surface, e.g. with the presence of oxides or biofilms, modifies the kinetics of deposit formation; and 3) electrolyte composition, pH, temperature and stirring. For instance, in seawater, Ca²⁺ and Mg²⁺ concentrations control the allotropic variety of CaCO₃ formed, e.g. Mg²⁺ inhibits the formation of calcite and vaterite. Hydrodynamic conditions near the electrode also influence the deposit composition since conditions regulate the mass transport at the electrode–solution interface. Below 10 °C, aragonite is not formed and the deposit stays thin. In the first stage of the deposit formation, an Mg-based compound is formed, followed by the growth of a Ca-based compound with time.

污染和气候变化问题正在要求采用先进的技术来隔离污染物，以降低毒性，对珊瑚和肋骨进行补救，并采用碳隔离以降低大气中的CO ₂水平。因此，钙质沉积看来是一种被忽视但可能有效的技术。钙质沉积物是海水中阴极保护的众所周知的沉淀副产物。沉积物由CaCO ₃和Mg（OH）₂的混合物制成。当将连接到电源的金属浸入海水中时，会形成钙质沉积物。到目前为止，除了促进珊瑚生长，防止海岸侵蚀，加强人工海洋结构和修复受污染的海水外，很少发现电化学钙质沉积的应用。在这里，我们回顾了电化学钙质沉积的原理和机理。钙质沉积物的生长，组成和力学性能受几个因素控制，例如1）电化学参数对Ca / Mg比的影响。例如，CaCO _3的形成在低阴极电位和低电流下是有利的，而Mg（OH）₂在高阴极电位和高施加电流下优先沉淀；2）金属电极的性质：尽管可以在固定电势下将石灰沉积在任何金属表面上，但是电化学反应和沉积物的组成受金属性质的控制。此外，电极表面的状态，例如在存在氧化物或生物膜的情况下，会改变沉积物形成的动力学。3）电解质的组成，pH，温度和搅拌。例如，在海水中，Ca ²⁺和Mg ^2+的浓度控制形成的CaCO ₃的同素异形性，例如Mg ²⁺抑制方解石和球ate石的形成。电极附近的流体动力学条件也会影响沉积物的组成，因为条件会调节电极与溶液界面的传质。低于10°C，不会形成文石，并且沉积物保持稀薄状态。在沉积物形成的第一阶段，形成基于Mg的化合物，然后随时间生长基于Ca的化合物。