磷酸盐改性脲甲醛缓控释肥的制备及性能研究

Study on Preparation and Performance of Phosphate Modified Urea Formaldehyde Slow-controlled Release Fertilizer

【目的】脲甲醛(UF)缓释肥料的养分释放周期过长,通常会达到1~2年,不利于作物对养分充分吸收。采用磷酸盐对UF改性,以缩短UF的养分释放周期,使缓控释肥料养分释放更匹配作物生长所需规律。【方法】采用溶液聚合配合原位挤出技术,在生成UF的过程中,将磷酸盐〔磷酸二氢钙(MCP)、磷酸二氢铵(ADP)和磷矿粉(PRP)〕穿插在形成的UF大分子链间,制备得到新型含氮、磷养分的缓控释肥料。采用TG、XRD和FTIR等手段对肥料的结构和官能团进行表征和分析,通过XPS研究肥料表面元素价态的变化。【结果】ADP在UF基体中分散性最好,对UF分子间氢键的破坏程度最大。处理后90 d,UF、MCP改性UF(MCP-UF)、ADP改性UF(ADP-UF)、PRP改性UF(PRP-UF)的氮累计释放率分别为68.46%、76.47%、80.45%、78.17%,比42 d时分别增加7.15、10.20、9.10和10.83个百分点。综上所述,磷酸盐的加入使改性缓控释肥料结晶度降低,氮磷养分具有优异的缓释效果。【结论】制备得到的缓控释肥料MCP-UF、ADP-UF和PRP-UF表明,UF中加入磷酸盐能改善氮磷养分释放,使其更匹配作物生长所需,有利于肥料的大批量工业化生产。

【Objective】The nutrient release cycle of urea-formaldehyde(UF)slow-release fertilizer is too long,usually up to 1-2 years,which is not conducive to the full absorption of nutrients by crops.In order to shorten the nutrient release cycle of UF,the phosphate was used to modify UF in order that the nutrient release of the prepared slow-controlled release fertilizer was more suitable for the law of crop growth.【Method】With the combination of solution polymerization and in-situ extrusion technology,in the process of generating UF,phosphates(calcium dihydrogen phosphate MCP,ammonium dihydrogen phosphate ADP and phosphate rock powder PRP)were interspersed between the formed UF macromolecular chains.A new type of slow-controlled release fertilizer containing nitrogen and phosphorus nutrients was prepared.The structure and functional groups of the fertilizer were characterized and analyzed by means of TG,XRD and FTIR,and the changes in the surface element valence state of the fertilizer were studied by XPS.【Result】ADP had the best dispersibility in the UF matrix and the greatest damage to the intermolecular hydrogen bonds of UF.After being treated for 90 days,the cumulative nitrogen release rates of UF,MCP-modified UF(MCP-UF),ADP-modified UF(ADP-UF)and PRP-modified UF(PRP-UF)were 68.46%,76.47%,80.45%and 78.17%,respectively,which increased by 7.15%,10.20%,9.1%,and 10.83%respectively compared with those at 42 d.In summary,the addition of phosphate reduced the crystallinity of the modified slow-controlled release fertilizer,and the nitrogen and phosphorus nutrients showed an excellent slow-release effect.【Conclusion】Slow-controlled release fertilizers MCP-UF,ADP-UF and PRP-UF were prepared.The addition of phosphate to UF improves the release of nitrogen and phosphorus nutrients,making it more suitable for crop growth,which is conducive to the large-scale in dustrial production of fertilizers.