Release kinetics of multi-nutrients from volcanic rock mining by-products: Evidences for their use as a soil remineralizer

Abstract Great quantities of stone by-products are stored alongside different exploiting mines in south Brazil, which becoming an unsustainable environmental issue. Powder materials andesite and dacite rocks were obtained from two mining companies Southern Brazil. The particle size classification the was determined by sieving. X-ray diffraction (XRD) technique used to identify mineral phases fluorescence (XRF) applied determine their chemical compositions. concentrations calcium (Ca), potassium (K), magnesium (Mg), phosphorus (P) silicon (Si) released inductively coupled plasma atomic emission spectrometry (ICP-AES). Dissolution rates measured Milli-Q water, solutions 0.1 mol L?1 citric acid, water acidified with 0.5 mol L?1 acetic as a function reaction times at 24–96 h (short-term), 96–5760 h (long-term). agitated continuously on mechanical rotatory shaker room temperature. parabolic diffusion, simplified Elovich, power models both time slots solid-solution reaction. results indicated that relationships quantity multi-nutrients well described equation: ln qt = ln a + b t. based release Ca, K, Mg, P Si steady state under far equilibrium conditions. not affected, within experimental uncertainty, water. Although dissolution unaffected its increased along time. minerals significantly affected pH solutions. multi-elements acid solution larger than another solutions, indicating exchangeable cations readily available solution. model intervals can contribute estimate multi-nutrients-supplying soil. present study provides solving issue associated Brazilian rock exploitation create alternative for soil fertilization more sustainable agriculture.