Feasibility evaluation of the use of mud residue from marble shop as soil remineralizer

Brazil is a major producer of dimension/ornamental stones, with a great diversity of raw materials. The sawing process transforms 20 to 30% of the extracted block into powder, with the generation of fine waste around 800,000 t/year. An alternative to reusing this waste is its application as a source of nutrients for the soil. This study evaluated the potential use of mud residue from a marble shop located in João Monlevade, Minas Gerais, as a remineralizer, based on fertility, mineralogical and chemical analysis performed by X-ray diffraction and X-ray fluorescence. For fertility, pH in CaCl₂ 0.01 mol L^-1, organic matter, aluminum saturation, potential acidity, sum of bases, cation-exchange capacity, base saturation, macro and micronutrients were determined. The studied residue has free silica, the sum of basis, and K₂O content in the range established by MAPA to be certified as a remineralizer. The sample contains 6.7% phyllosilicates, a source of faster K availability, and 19.4% K-feldspar, a slow-release source. Results described in this study indicate that residue can be a promising, efficient, and low-cost alternative to improve soil fertility. (author)