Análise do uso de resíduos da mineração de brita para liberação de nutrientes no solo

Abstract

Rock remineralization is a natural fertilization technique that uses ground rocks to restore nutrients in depleted soils. Granite residue is a low-cost material and an alternative to chemical fertilizers, whose prices have risen due to the recent war between Russia and Ukraine. This study aimed to evaluate, from a physicochemical perspective, the potential of granite mining residue as a biofertilizer. Physical characterization tests (real and apparent density, wet sieving), chemical analysis by X-ray fluorescence (XRF), and potassium release kinetics using citric acid at different concentrations were performed. The material presented a particle size distribution suitable for agricultural application, with fine fractions that favor the gradual release of nutrients. The chemical composition showed a predominance of SiO₂ (62.3%) and significant levels of K₂O (7.6%), CaO (3.0%), and P₂O₅ (1.1%), indicating agronomic potential. The reduction in particle size increased potassium solubilization, demonstrating greater reactivity under acidic conditions. It is concluded that the granite residue has physicochemical properties compatible with agricultural use as a complementary nutrient source, partially meeting the requirements established by Normative Instruction No. 5/2016 of the Brazilian Ministry of Agriculture, Livestock and Supply (MAPA). Determination of free quartz and potentially toxic elements, as well as field tests, is recommended to confirm efficiency and regulatory compliance.