Caracterização física, química e mineralógica de subprodutos do processo de beneficiamento metalúrgico de manganês e níquel para fins de uso agrícola

Abstract

Solid waste generation is inherent to most industrial activities. One known sector is the steel/metallurgical industry, which due to the characteristics of its production process, generate by-products such as slags. Researches to improve their production processes are means that industries seek to reduce the generation of their waste or identify new alternatives of destination. By physical-chemical analysis, it is possible to characterize by-products and identify feasible alternatives of uses in other industrial sectors, transforming these into new commercial products. In that context, the present work was carried out, in order to explore the physical, chemical and mineralogical characteristics of two by-products from the metallurgical beneficiation process of manganese and nickel, commonly known as slags. Specifically, it was evaluated the Iron-Silicon-Manganese (FeSiMn) reduction and nickel refining slags, with the objective of studying the potential use of these materials in the agricultural sector as a soil acidity corrective material, in addition, it was also analyzed the capacity of these materials solubilize the manganese (Mn), silicon (Si) and nickel (Ni) elements. The analyzes were conducted in accordance with the Official Manual of Analytical Methods for Fertilizers and Corrective Materials and the Normative Instructions - IN nº. 27/2006 and IN nº 35/2006, established by the Ministry of Agriculture, Livestock and Supply – MAPA (BRAZIL, 2006a, 2006b). In parallel, mineralogical analyzes were done by the X-ray diffraction, in order to identify minerals with neutralizing characteristics, as well as Scanning Electron Microscopy (SEM), which allows to identify the association of elements with minerals. As a result, both slags presented the capacity of neutralizing the soil acidity, which corroborated with the identification of some minerals which have neutralizing characteristics performed by the X-ray diffraction. However, only nickel refining slags met the chemical requirements determined by MAPA for acidity correctives, in addition solubilizing the Ni and Si elements, which may become a differential when compared to commercial agricultural limestone, thus enabling the continuity of research to register these as a soil acidity corrective material in MAPA.