<p>NdFeB hydrochloric leaching residue (NHLR) is an iron-based solid waste generated from the NdFeB magnet scrap recycling process, containing 0.2 ~ 1.0 wt.% rare earth oxides encapsulated by the dense iron oxide phases. Traditional hydrometallurgical processes struggle to extract these trace rare earth elements effectively. Crystalline silicon cutting waste (SCW) is another solid waste originating from the photovoltaic industry, which is difficult to purify to solar-grade silicon purity (6N) due to its oxide layer. To achieve resource utilization, a synergistic process was proposed in this work to convert these two industrial wastes into ferrosilicon alloy and a reduction slag that is conducive to rare earth extraction. Experimental results reveal that the dense structure of NHLR can be effectively destroyed by the SCW and iron oxides were reduced at high temperatures. The particle size of the obtained ferrosilicon alloy is improved by decreasing the amount of SCW, increasing the reduction temperature, and extending the reduction time. Comparing to the initial NHLR, the leaching performance of rare earth elements in the reduction slag was enhanced. The leaching efficiency of cerium (Ce), praseodymium (Pr), and neodymium (Nd) increased by 42.74, 12.47, and 12.64% respectively using low-concentration hydrochloric solutions. Moreover, the tailings after rare earth extraction are mainly calcium silicate, which can be used as raw materials for cement. Therefore, the present method achieves valorization utilization and “zero waste” treatment of two typical industrial solid wastes, contributing to the green development of the rare earth industry.</p> Graphical Abstract <p></p>