The treatment of smelting slag has attracted much attention nowadays. This study investigates the influence of Na₂S, CuSO₄, and FeCl₃ on sulphidizing flotation of copper oxide. The results show that a proper Cu²⁺ concentration can increase the sulphidizing effect of copper oxide, while Fe³⁺ inhibits the sulphidizing effect. Further analysis shows that Cu²⁺ ions can reduce the surface potential, increase the S²⁻ adsorption, then generate more polysulfide, and therefore promote the sulphidizing flotation. However, Fe³⁺ ions would increase the surface potential, reduce the S²⁻ adsorption, generate more sulfur element, and therefore inhibit the sulphidizing flotation.

In this work, 316L stainless steel samples were prepared by selective laser melting (SLM) and the effects of the bulk laser energy density on the resulting density and mechanical properties were evaluated. The results show that the density and mechanical properties of SLM 316L stainless steel first improved and then deteriorated with increasing bulk laser energy density. When the bulk laser energy density was 70.2 J/mm³, the obtained tensile strength and yield strength vertical to the building direction were 720 and 546 MPa, respectively, which surpass the design requirements for forged 316L stainless steel. The influence of the microstructure on the mechanical properties of SLM 316L stainless steel is also discussed. The purpose of this research was to provide experimental data and a theoretical basis for high-performance 316L stainless steel fabricated by SLM.