54 In order to evaluate the success of technological processes or its individual stages of material enrichment, some concepts and methods have been introduced in the recycling/ore drfessing technique, which the management puts too little attention specialy in the daily practice of waste management or pursues other goals. Devices for separating individual components from a mixture of waste/mineral raw materials generally operate on the principle of one input flow and at least two outflow currents. In Figure 5., the different separation rates with two or more mass flows are schematically shown. Figure 5 - Separation processes with two or more outlet mass flows [18]. The efficiency of the separation processes is determined by the mass yield Rm, the purity level Pm and the beneficial yield of useful substance Rc. The mass yield is given by the mass fraction of the rich substance used in any product. Speaking generally, the concept of mass yield Rm refers to the product of an enriched useful substance, and the degree of purity Pm takes into account the degree of contamination/purity of the useful product. ( ) 100 % 2 1 2 0 1 + − = x x x x R x m 1 100 % ) ( 1 1 1 1 + = x y x P x m 2 The beneficial yield of useful substance Rc is an important technological parameter, where the inlflow and outflow Cm is generally given in % by weight instead in mass units. By utilizing the beneficial yield of useful substance Rc, the technological efficiency of various appliances, individual technological processes or the whole process of recovery/recycling of waste/mineral resources can be described. ( ) 100 % 0 0 1 1 1 = x C x C R x c 3 In recycling production processes, the substances present for economic purpose are transformed, separated and/or bonded and thus brought into a different form that is useful for other purposes of use. The recycling process always follows the production process and can be designated as another type of production in which other substances and waste are processed. Both processes are common in both cases that there are one or more input streams and different output currents. Efficient management of production processes and the reuse of secondary raw
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