This work illuminates a practical design approach for developing economically viable and thermodynamically feasible metallurgical manufacturing processes. Successively refined economic potential estimators serve as the driving force for systematically advancing the design effort. The focus on process economics aims at identifying design inferior options and discarding process configurations with marginal economic performance early in the development cycle. In the proposed approach, novel process ideas evolve gradually as prescribed by the decision hierarchy by Douglas [AIChE J. 31 (1985) 353] modified to address metallurgical processes. Due to lack of heuristics in modeling reaction networks, a bi-level mathematical program for the simultaneous optimization of economic performance and complex multi-phase thermodynamic equilibrium is developed. The discussion includes the derivation of a thermodynamically consistent framework for integrating empirical atom interaction coefficients into the total Gibbs free energy model. The article demonstrates the beneficial use of mathematical modeling and non-linear mathematical programming within a systematic design framework. (C) 2003 Published by Elsevier B.V.