Abstract: The initial feed liquid was lanthanum cerium sulfate solution produced from Baotou mixed rare earth ore after intensive roasting with concentrated sulfuric acid, water leaching, neutralization and impurity removal, and P₅₀₇ transformation before pre-classification. The precipitant was magnesium bicarbonate solution, which was prepared by alkali conversion and carbonization of the magnesium sulfate wastewater. La&Ce rare earth polishing powder was successfully prepared by precipitation, fluorination, roasting, crushing, and grading. The morphology, phase, and polishing performance of La&Ce polishing powder were characterized. The results showed that La&Ce rare earth polishing powder particles are well-formed and evenly distributed. The K9 glass was used for performance testing of prepared polishing powder. The polishing results showed that the accumulated polishing rate reaches 352 mg after 120 minutes, and the surface roughness Sa reduce from the initial 2.0 nm to 1.742 nm. In contrast, lanthanum-cerium polishing powder prepared by precipitation of (LaCe)Cl₃ with NH₄HCO₃ achieves a lower polishing rate of only 299 mg under the same polishing conditions,and the surface roughness Sa decrease to 1.767 nm from the initial 2.0 nm. As a consequence, the comprehensive performance of rare earth polishing powder prepared by Mg(HCO₃)₂ precipitation (LaCe)₂(SO₄)₃ process is superior while maintaining the same polishing quality.

Key words: precipitate, preparation, polishing powder, polishing performance