Synthesis of layered double hydroxides derived from blast furnace slag

The objective was to develop an efficient and cost-effective adsorbent to stabilize contaminants present in alternative materials used in civil engineering, such as sediments and fly ash. The synthesis method employed included acidic leaching at a constant pH, followed by precipitation, allowing for the production of LDH. The optimization of synthesis parameters was crucial to determine the boundary conditions for the crystallization of this mineral phase. Among the parameters studied for the optimization of LDH synthesis from blast furnace slag were the concentration of HCl, aging time and temperature, pH during aging, as well as the time and temperature of crystallization. The optimal conditions were identified as an HCl concentration of 4 M, an aging time of 30 min at 90 °C, a pH of 12.5, a crystallization time of 12 h, and a crystallization temperature of 70 °C. The synthesized. LDH exhibited structural characteristics similar to those observed in other studies, confirming the high quality of the product. This demonstrates that blast furnace slag is a suitable raw material for the synthesis of high quality LDH, while minimizing the formation of undesirable secondary mineral phases. • The blast furnace slag was successfully converted into LDH. • The synthesized LDH exhibited a mesoporous structure with few micropores. • Small amounts of undesirable calcite were present in the synthesized LDH.