Flue gas desulfurization gypsum (FGDG) is one of the typical bulk solid wastes. With its vast production and considerable storage capacity, it accumulates in substantial quantities, occupies an extensive amount of land, and poses a severe pollutant threat to the ecological environment. To achieve large-scale consumption of FGDG, this study puts forward a method for the soil utilization and ecological reconstruction involving the co-pyrolysis of FGDG and biomass. The main emphasis is placed on exploring the alterations in leaching toxicity and plant-available elements under diverse conditions of temperature, biomass addition, and pyrolysis time. The co-pyrolysis parameters were optimized, and the changes in mineral composition of FGDG and biomass under different pyrolysis circumstances were investigated using XRD and SEM characterization methods. The experimental outcomes demonstrated that the optimal pyrolysis conditions were a temperature of 700 °C, a biomass content of 60 %, and a pyrolysis time of 5 h. The toxic and harmful substances within FGDG were solidified and stabilized, achieving a harmless treatment of FGDG. Simultaneously, the usable elements for plants were released. Through the analysis of mineral composition and microstructure, it was discovered that the pyrolysis products contain a considerable amount of CaSO4 and C, and the microstructure mainly consists of porous aggregates. The reason for the reduced leaching efficiency of toxic and harmful substances might be attributed to the formation of stable minerals such as heavy metals through crystallization and vitrification mineralization after the removal of crystal water from FGDG. Under the reduction effect of C, the available elements for plants are liberated. This study furnishes a theoretical basis for the industrial application of FGDG and biomass for large-scale soil utilization treatment.

中文翻译：

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烟气脱硫石膏与生物质协同热解产物的土壤利用分析


烟气脱硫石膏 （FGDG） 是典型的散装固体废物之一。凭借其庞大的产量和相当大的储存能力，它大量积累，占用大量土地，对生态环境构成严重的污染威胁。为了实现 FGDG 的大规模消耗，本研究提出了一种涉及 FGDG 和生物质共热解的土壤利用和生态重建方法。主要重点是探索在温度、生物量添加和热解时间等不同条件下浸出毒性和植物可利用元素的变化。优化了共热解参数，并使用 XRD 和 SEM 表征方法研究了不同热解情况下 FGDG 矿物成分和生物质的变化。实验结果表明，最佳热解条件为温度 700 °C，生物量含量为 60 %，热解时间为 5 h。FGDG 内的有毒有害物质被固化和稳定，实现了对 FGDG 的无害化处理。同时，植物的可用元素被释放。通过矿物成分和微观结构分析发现，热解产物中含有相当数量的 CaSO4 和 C，微观结构主要由多孔聚集体组成。有毒有害物质浸出效率降低的原因可能是由于 FGDG 中去除结晶水后，通过结晶和玻璃化矿化形成了稳定的重金属等矿物。在 C 的还原作用下，植物的可用元素被释放出来。 本研究为 FGDG 和生物质在土壤大规模利用处理中的工业应用提供了理论依据。