Justification of Complex Physical–Chemical Criteria for Flotation Processing Efficiency in Waste Recycling Using Paper De-Inking as an Example

In this work, a set of methods for the study of the physical–chemical properties of flotation processing products was applied to establish parameters for the technological mode of anthropogenic raw material flotation processing using waste paper as an example. The proposed methods include the criterion Ef estimation, which characterizes the interfacial characteristics during flotation, and the criterion J determination, which characterizes the degree of purification of the obtained paper mass. The estimation of criterion Ef is based on the measurement of electric potential difference during flotation. The estimation of criterion J is based on spectrophotometric studies of the flotation product’s optical properties. Based on dispersion analysis, it was established that the proposed criteria are statistically dependent on the variation of the flotation purification mode parameters. The results of the study of flotation processing products show that the criterion Ef is sensitive to the recovery selectivity of dye particles in the froth product. In conjunction with the criterion of optical purity, J, it can be used to assess the effectiveness of proposed solutions of hardware design and the technological mode of flotation separation.