<p>In recent years, the rapid development of the photovoltaic industry has led to an increased demand for raw materials used in metallurgical-grade silicon (MG-Si) production, resulting in a large amount of silicon slag. MG-Si refining slag contains large amounts of underutilized silicon resources. Therefore, developing an effective method for silicon recovery is crucial. In this study, a depressant sodium hexametaphosphate (SHMP) was introduced for the flotation separation of silicon from metallurgical-grade silicon (MG-Si) refining slag using 2^# oil as a collector and a frother. The impeller speed was set to 2000&#xa0;rpm, and the slurry pH was adjusted to 8, followed by 4&#xa0;min of conditioning during the flotation process. Flotation results revealed that with the increasing concentration of SHMP, the recovery rate of Si increased from 42.47% ± 1.77% to 77.45% ± 4.01%. Additionally, by controlling particle size, it was found that as particle size decreases, the recovery rate continues to increase. This study seeks to provide a more feasible and effective technical route for the large-scale recovery of silicon from MG-Si refined slag. The development of such a route is highly significant for reducing the loss of silicon resources and the clean and sustainable development of silicon industry.</p>