Systematic Selection of Waste from Run-of-Mine Coal Processing as Sustainable Raw Materials for Organo-Mineral Fertilizer Production

The main focus of this study, from a sustainable perspective, was to develop mineral circularity actions for the minimization of environmental impacts, generated over decades by the processing of run-of-mine (ROM) coal in the Catarinense coal basin–Brazil (CCB–Br), from the use of potential residual fractions (candidate residues) as raw materials for the production of organo-mineral fertilizers, or OMFs (candidate products). Therefore, the objective was to assess the potential of the residual fractions, generated in the distinct phases of ROM coal processing, as candidate waste for valorization, contributing directly to the advancement of the Sustainable Development Goals (SDGs). The samples from ROM processing resulted in 24 waste fractions identified by geological characteristics and a sustainable processing methodology. These fractions were subjected to a systematic analysis using the criteria for waste valorization CPQvA (classification (C) of hazardousness, potentiality (P), quantities/viability (Qv), and applicability (A)). Two samples were identified with significant potential for valorization in the agro-industry as sustainable raw materials for the organo-mineral fertilizers. Both samples exhibited neutral stock pH values (7.0 and 7.1), low percentage Fe2O3 content (4.2% and 3.2%), low SO3 content (0.5% and 1.2%), and low total sulfur content (1.0%). These characteristics qualified the studied ROM samples as raw materials suitable for the production of organo-mineral fertilizers (OMFs), and which comply with Brazilian legislation.