We focus on a novel and economical route for the synthesis of Si fertilizer via the calcination method using lithium pyroxene acid-leaching residues as the starting materials.The molar ratio of Si/K/Ca of 1:1.4:0.8,ca...We focus on a novel and economical route for the synthesis of Si fertilizer via the calcination method using lithium pyroxene acid-leaching residues as the starting materials.The molar ratio of Si/K/Ca of 1:1.4:0.8,calcination temperature of 900℃and calcination time of 120 min were identified as the optimal conditions to maximize the available Si content of the prepared Si fertilizer.The performance of the resulting product satisfies the Chinese agricultural standard for silica fertilizers,providing a new solution for the large-scale harmless and sustainable reuse of lithium pyroxene tailings.The X-ray diffraction(XRD)and Fourier transform infrared spectroscopy(FTIR)characterization elucidated the formation mechanism of silica fertilizers,and identified KAlSiO_(4)and K_(4)CaSi_(3)O_(9)as the primary silicates products.Observation of the surface morphology of the samples was conducted by scanning electron microscopy(SEM)and X-ray energy dispersive spectrometry(EDS),and compositional analysis of the micro-regions.The acceleration action of CaCO_(3)in the decomposition process of lithium pyroxene acid-leaching residues was demonstrated by the thermogravimetry-differential scanning calorimetry(TG-DSC)test.Determination of heavy metal elements in Si fertilizer was performed by ICP-OES.Potting experiments confirmed that the best growth of pakchoi was achieved when 5 g·kg^(-1)of Si fertilizer was applied.These evidence suggests that the Si fertilizer prepared in this study is a promising candidate for a silica-supplemented soil.展开更多
文摘We focus on a novel and economical route for the synthesis of Si fertilizer via the calcination method using lithium pyroxene acid-leaching residues as the starting materials.The molar ratio of Si/K/Ca of 1:1.4:0.8,calcination temperature of 900℃and calcination time of 120 min were identified as the optimal conditions to maximize the available Si content of the prepared Si fertilizer.The performance of the resulting product satisfies the Chinese agricultural standard for silica fertilizers,providing a new solution for the large-scale harmless and sustainable reuse of lithium pyroxene tailings.The X-ray diffraction(XRD)and Fourier transform infrared spectroscopy(FTIR)characterization elucidated the formation mechanism of silica fertilizers,and identified KAlSiO_(4)and K_(4)CaSi_(3)O_(9)as the primary silicates products.Observation of the surface morphology of the samples was conducted by scanning electron microscopy(SEM)and X-ray energy dispersive spectrometry(EDS),and compositional analysis of the micro-regions.The acceleration action of CaCO_(3)in the decomposition process of lithium pyroxene acid-leaching residues was demonstrated by the thermogravimetry-differential scanning calorimetry(TG-DSC)test.Determination of heavy metal elements in Si fertilizer was performed by ICP-OES.Potting experiments confirmed that the best growth of pakchoi was achieved when 5 g·kg^(-1)of Si fertilizer was applied.These evidence suggests that the Si fertilizer prepared in this study is a promising candidate for a silica-supplemented soil.
