A Study on the Synthesis of Lithium Carbonate (Li2CO3) from Waste Acidic Sludge

In this study, the synthesis of lithium carbonate (Li₂ CO₃ ) powder was conducted by a carbonation process using carbon dioxide gas (CO₂ ) from waste acidic sludge based on sulfuric acid (H₂ SO₄ ) containing around 2 wt.% lithium content. Lithium sulfate (Li₂ SO₄ ) powder as a raw material was reacted with CO₂ gas using a thermogravimetric apparatus to measure carbonation conditions such as temperature, time and CO₂ content. It was noted that carbonation occurred at a temperature range of 800°C to 900°C within 2 hours. To prevent further oxidation during carbonation, calcium sulfate (CaO₄ S) was first introduced to mixing gases with CO₂ and Ar and then led to meet in the chamber. The lithium carbonate obtained was examined by inductively coupled plasma–mass spectroscopy (ICP-MS), X-ray diffraction (XRD) and scanning electron microscopy (SEM) and it was found that of lithium carbonate with a purity above 99% was recovered.