In the field of pyrometallurgy there is a complex interplay between many physical phenomena such as convective, conductive, and radiative heat transfer, stress and strain, electrical current flow, fluid flow and the effects of magnetohydrodynamics, phase change, reaction kinetics, and combustion. Including all these physical phenomena into one stable solver and applying it to a complex multi-region domain can be troublesome. This makes a good case for pyrometallurgical multiphysics models to have separate domain regions based on the physics required, using less complicated solvers in each, but couple them to still obtain insight into the complex system. The multiphysics models developed by the authors usually require custom physics solvers to be created based on case specific model requirements as well as assumptions and simplifications that need to be made. Using a reliable, robust, and efficient coupling package such as preCICE has facilitated the rapid development of these types of custom mulitphysics solvers. Two example systems will be used to demonstrate the scope and complexity of the types of problems that have been tackled. The first considers an electric arc furnace model, which demonstrates the coupling of electrical current flow through the molten slag and alloy baths and the resulting Joule heating and Lorentz forces due to the magnetic field. The Lorentz forces and buoyancy forces induce flow in the molten slag bath, which in turn, induces flow in the alloy bath due to the shear forces between them. In the second example, a rotary kiln model was developed to approximate the throughput and the degree of metallisation of a pre-reduction process. The model demonstrates the interaction between a continuous particulate flow model and the flow of hot freeboard gasses. Combustion and reaction kinetics were also included within the particulate region and freeboard together with convective, conductive, and radiative heat transfer.