This doctoral thesis focused on the optimisation of the pyrometallurgical processing of metalliferous residues from the petroleum-, engergy- and fertiliser-industry to ferrovanadium and ferronickelmolybdenum, in an electric arc furnace. The basis of the optimisation was a comprehensive evaluation and validation of the relevant parameters on the oxidation behavior, as well as the selectivity of the oxidation of vanadium, phosphorus and molybdenum. The general objective of the work covered on the one hand the reduction of material-, time- and energetic consumption as well as the decrease of the resulting residual substance quantities and on the other hand, also the metal-yield of the process should be increased. The initial investigations focused on the selectivity of the oxidation between vanadium and phosphorus, afterwards by means of MODDE 7,0 a mathematical model was developed, which offered the possibility to control the V-content in the alloy during the process. Furthermore, the parameters and their influence on the dephosphorisation and the arising molybdenum loss could be determined by two models. For the practical investigations thermodynamic calculations preceded by means of HSC 5.11, also process- and rawmaterial-analyses gave important information for the development of effective process-models, which were used for the optimisation of the sub-processes.