Studying the Effect of Nickel, Copper, and Zinc on the Precipitation Kinetics and the Composition of Ca-Carbonates for the Integrated Process of Co2 Mineralization and Brine Mining

Brine mining of energy-relevant elements (EREs) requires the separation of transition metals from major cations in order to create high-purity streams. Precipitation of carbonates could be used as a separation method leaving EREs in the supernatant, therefore opening the possibility to integrate carbon dioxide (CO2) mineralization with brine mining. Major challenges are that the reaction should reach completion in few days and the inclusion of transition metals in the carbonates should be avoided. In this paper, we report an experimental and modeling work on the precipitation of calcium (Ca) carbonate in the presence of nickel (Ni), copper (Cu), and zinc (Zn). Brines of various compositions were tested to simulate brine enrichment. Atmospheric conditions were applied to study the effect of the metal concentration on the precipitation kinetics and the composition of the carbonates produced. The experiments were run in batch and monitored with inline pH and conductivity probes. Results s...