Single cascades of centrifuges for simultaneously concentrating three components of separable mixtures are considered. A method is proposed for optimizing the parameters of a cascade with expansion of flow from squared sections that has an additional product flow. By way of an example, the correctness of the proposed method was checked by comparing with known data the optimization of a squared cascade with an additional product stream. It is shown that on separating a three-component mixture and concentrating the intermediate mass components under the same external conditions a cascade with “expansion” of the flow turns out to be more efficient from the standpoint of the relative summary flow.