Research on Impurity Removal Processes in the Production of Sodium Carbonate from Natural Soda Ash

To address the high impurity content in sodium carbonate (Na 2 CO 3 ) from natural soda ash, which is unsuitable for advanced industries like battery manufacturing, this study developed an innovative “elutriation + adsorption” process using samples from Tongbai, China. By exploiting Na 2 CO 3 ’s temperature-dependent solubility (20°C−30°C), saturated elutriation achieved the removal of 75%−85% of Ca, Fe, Mg, Zn, and Cu impurities, while subsequent adsorption using modified clinoptilolite (45% increased surface area, 60% enhanced ion-exchange capacity) enabled 98.78% potassium removal efficiency. The integrated process delivered 99.71% total impurity reduction, surpassing the first-grade threshold of battery-grade Na 2 CO 3 (T/HNSDCHYXH001-2023) with < 0.003% residual K content. Crucially, this zero chemical-addition approach retained the "natural" production integrity while achieving lower energy consumption than conventional crystallization methods, positioning it as a sustainable solution for upgrading natural soda ash to battery-industry specifications.