Abstract

To recover degraded paddy fields, low-cost supplies of Ca, Si, and Fe are necessary. Steelmaking slag contains these three elements, which makes it a potential material for amending paddy soil. To simultaneously supply Ca, Si, and Fe to paddy field, the optimum slag chemistry as a fertilizer was found in our previous study to have a basicity of about 1.6 and FeO concentration of about 25 mass%, referring to the CaO–SiO₂–FeO system. The optimum slag structure, which is the coexistence of the CaO–SiO₂–FeO glassy phase and 2CaO·SiO₂ soil solution, can be obtained by quenching the molten slag from 1573 K. In this study, to evaluate the effects of the above novel slag fertilizer on soil amendment, a column test using an actual paddy soil was conducted. During the 2 months of testing, the concentrations of Fe, Ca, and Si in the soil solution were increased by applying the novel fertilizer, compared to two commercial fertilizers made of steelmaking slag. From the soil analysis before and after the column test, the concentrations of easily reducible iron oxide, exchangeable Ca, and adsorbed silica of the paddy were also increased by the novel slag fertilizer. In addition, a model for predicting the time-dependent changes in soil conditions was established using PHREEQC software. This model effectively estimated the daily changes in pH, oxidation and reduction potential, and the concentrations of each element in the soil solution.

Graphical Abstract

中文翻译：

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使用CaO–SiO 2 –FeO系统的玻璃态，由炼钢炉渣制成的新型肥料的设计。第二部分：水稻土环境中新型肥料的评价

摘要

为了恢复退化的稻田，需要低成本的Ca，Si和Fe供应。炼钢炉渣包含这三个元素，使其成为改良稻田土壤的潜在材料。为了同时向稻田供应钙，硅和铁，在我们先前的研究中发现，作为肥料的最佳矿渣化学具有约1.6的碱度和约25质量％的FeO浓度，是指CaO–SiO ₂ – FeO系统。最佳炉渣结构，即CaO–SiO ₂ –FeO玻璃态相与2CaO·SiO ₂共存通过将1573 K的熔融矿渣淬火可以得到土壤溶液。在本研究中，为了评估上述新型矿渣肥料对土壤改良剂的影响，进行了使用实际稻田土壤的柱试验。在测试的两个月中，与两种由炼钢炉渣制成的商业肥料相比，通过施用新型肥料提高了土壤溶液中铁，钙和硅的浓度。从柱试验前后的土壤分析来看，新型矿渣肥料还提高了稻田易还原的氧化铁，可交换的Ca和吸附的二氧化硅的浓度。此外，使用PHREEQC软件建立了预测土壤条件随时间变化的模型。该模型有效地估算了pH，氧化和还原电位的每日变化，

图形概要