<p>The alkaline decomposition process is currently the mainstream technology for recovering rare earths from monazite concentrates. However, this technology has the problems of high alkali consumption and low efficiency. A mechanochemical activation method of monazite concentrates for the alkaline decomposition is proposed here. The influence of the mechanochemical activation method on the alkaline decomposition of monazite has been investigated using characterization techniques such as XRD, ICP, and SEM-EDS, and the reaction mechanism and reaction kinetics analyzed. The results demonstrate that the alkaline decomposition efficiency of monazite via the mechanochemical activation-alkaline decomposition process (M-D) can reach 94.6%, in contrast to merely 38.6% achieved by the mainstream high-pressure alkaline decomposition process (H-D). Furthermore, the M-D process eliminates the need for high temperature and pressure conditions, and alkali consumption can be reduced by nearly 40%. The alkaline decomposition of monazite through the M-D process is dominated primarily by chemical reaction kinetics. The M-D process enhances monazite decomposition not only by reducing large monazite particles into highly reactive fine particles but also by disrupting the encapsulation of monazite particles by decomposition products (RE(OH)₃), thus accelerating the decomposition reaction. This research provides a better understanding of the alkaline decomposition of monazite and supports for the development and optimization of monazite alkaline decomposition processes.</p>