Improving service life of magnesium reduction steel retorts against creep collapse by structural modification

•The effect of supports on creep life of Mg reduction retorts is modeled by 3D FEM.•Application of supports extends retort life at the cost of greater retort mass.•An external support (1 = 500, t = 10 mm) increases service life from 60 to 125 days.•Economic optimization suggests an external sleeve (l = 500, t = 10 mm).•The positive effect of retort cross-section outweighs that of support application. Reduction steel retorts are extensively used in the production of magnesium by the Pidgeon process. As the equipment is subjected to elevated temperatures, it expires within two months as a consequence of excessive creep deformation. This study was conducted to prolong the life of retorts and reduce Mg production costs through the application of supports in the vulnerable mid-sections of tubes and changing their cross-sections. A finite element model was crafted to test the productivity of the proposed designs. Results from actual small-scale retorts validated finite-element model predictions. It was found that supported retorts demonstrate significant improvement in terms of operational life over the unsupported ones. Via economic analysis, optimal design for Mg-production steel retorts was determined to comprise an externally reinforced support 50 cm long, 10 mm thick placed in the middle of an otherwise unsupported retort.