Extracting lithium from the H2SO4 leaching solution of bauxitic claystone via co-precipitation methods without addition of Al source

Newly mined bauxitic claystone resources have received attention due to the rapidly growing demand for lithium. However, existing methods for extracting lithium from bauxitic claystone are still difficult and costly. This study proposed a novel aluminum hydroxide precipitation method to improve the extraction rate of Li by cleverly utilizing Al from bauxitic claystone. First, the ball-milled and calcined bauxitic claystone samples were leached by sulfuric acid to obtain a leaching solution with a high concentration of Al3+. Then, a NaOH solution was added to form amorphous aluminum hydroxide to adsorb Li+. The precipitation rate of Li+ reached 97.2% under the suitable precipitation conditions. Lastly, the precipitate was calcined and leached with deionized water to extract lithium. Li+ reached a water-leaching rate of 86.13%. According to the X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FT-IR) results, the prepared precipitate was mainly amorphous aluminum hydroxide and part was composed of a gibbsite phase. The elution experiment showed that the amorphous aluminum hydroxide had good adsorption selectivity for Li+. In addition, Al2O3 could be recovered from the solid phase after water-leaching, which can significantly reduce the cost.