Synthesis of metal powders via reduction of carbonates in self-stirred autoclave

Abstract

Commercial carbonates were used as the metal sources for synthesis of metal powders, and a self-stirred autoclave device was proposed to accelerate the complete reduction of carbonates. Fluent software was employed to simulate the system and analyze the distribution of the solution and particles in the autoclave, Ni and Cu powders were synthesized to verify the experiment's feasibility. Results indicate that sufficient mixing of reactants, solvents, and intermediate product can be maintained in the improved self-stirred autoclave during the reaction process, which is beneficial for accelerating the full reduction of carbonates and improving the uniformity of metal powders. Additionally, because basic carbonates can neutralize the hydrogen ions produced by the reduction reaction, and thus Ni powders can be synthesized without NaOH added, which is beneficial for controlling particle morphology and saving reaction time. Well-dispersed Ni and Cu powders were synthesized via the present route, which is possible to promote the reduction preparation of ultrafine metal powders for other insoluble and slightly soluble metal salts.