Seesanong Somkiat, Seangarun Chaowared, Boonchom Banjong, Laohavisuti Nongnuch, Chaiseeda Kittichai, Boonmee Wimonmat
Department of Plant Production Technology, School of Agricultural Technology, King Mongkut's Institute of Technology Ladkrabang, Bangkok10520, Thailand.
Advanced Functional Phosphate Material Research Unit, Department of Chemistry, School of Science, King Mongkut's Institute of Technology Ladkrabang, Bangkok10520, Thailand.
ACS Omega. 2021 Aug 17;6(34):22065-22072. doi: 10.1021/acsomega.1c02660. eCollection 2021 Aug 31.
Triple superphosphates [TSPs, Ca(HPO)·HO] were produced by exothermic reactions of oyster shells and different concentrations of phosphoric acid (10, 20, 30, 40, 50, 60, and 70% w/w) in a molar ratio of 1:2. The percentage yields, PO and CaO contents, metal impurities, and thermal behaviors of all the as-prepared products are dependent on the concentrations of phosphoric acid added during the production processes, which confirm to get the best optimum of 60% w/w phosphoric acid. All the as-prepared products were characterized by several characterization methods [X-ray fluorescence, thermal gravimetric/derivative thermal gravimetric analysis, powder X-ray diffraction, Fourier-transform infrared spectroscopy, and scanning electron microscopy], verifying that all the obtained compounds are TSP that can be used as fertilizers without metal toxic contaminants. From the successful results, the method for TSP production can be applied in the fertilizer industry based on starting waste materials of oyster shells that can replace the use of unsustainable phosphate or calcium minerals obtained from nonliving things.
通过牡蛎壳与不同浓度（10%、20%、30%、40%、50%、60%和70% w/w）的磷酸以1:2的摩尔比进行放热反应来生产重过磷酸钙 [TSPs，Ca(HPO₄)₂·H₂O]。所有制备产物的产率百分比、P₂O₅和CaO含量、金属杂质以及热行为均取决于生产过程中添加的磷酸浓度，这证实使用60% w/w的磷酸可获得最佳效果。所有制备产物通过多种表征方法 [X射线荧光、热重/微商热重分析、粉末X射线衍射、傅里叶变换红外光谱和扫描电子显微镜] 进行表征，验证了所有获得的化合物均为重过磷酸钙，可作为无金属有毒污染物的肥料使用。基于这些成功结果，重过磷酸钙的生产方法可应用于肥料工业，该方法以牡蛎壳这种起始废料为基础，能够替代使用从无生命物质中获取的不可持续的磷矿石或钙矿石。
