The present paper describes a mathematical formalism for blending to obtain formed fuels from industrial waste. The offered methodology assures obtaining fuels of required technological properties, which result in, for example, a limited gram fraction of chlorine in dry mass of fuel and an appropriate calorific value in the working state. The procedure is illustrated by a simple example of calculations connected with the forming fuels from the waste obtained in the production and processing of cellulose pulp, paper and cardboard. The application of the mathematical formalism to additional limitations resulting in the extension of the technological condition and its linking to the model of generator processes will allow us to estimate the quality of synthetic gas produced from the formed fuels. (c) 2008 Elsevier Ltd. All rights reserved.