聚磷酸钙镁的制备研究  

Study on preparation of calcium magnesium polyphosphate

作　　者：苗林平 许淼 王辛龙 严正娟 许德华 杨晶旭 MIAO Linping;XU Miao;WANG Xinlong;YAN Zhengjuan;XU Dehua;YANG Jingxu(Ministry of Education Research Center for Comprehensive Utilization and Clean Processing Engineering of Phosphorus Resources,School of Chemical Engineering,Sichuan University,Chengdu 610065,China)

机构地区：[1]四川大学化学工程学院,教育部磷资源综合利用与清洁加工工程研究中心,四川成都610065

出　　处：《无机盐工业》2022年第9期63-68,共6页Inorganic Chemicals Industry

基　　金：国家自然科学基金,面上项目“基于农业需求的聚磷酸铵聚合度分布调控机理研究”(32172677)。

摘　　要：针对湿法磷酸渣和磷尾矿难以利用的问题,提出了一种焙烧湿法磷酸渣和磷尾矿的混合物制备聚磷酸钙镁肥的策略。基于磷尾矿分解率得出磷尾矿与磷酸渣的适宜质量比为0.30,在此条件下磷尾矿的分解率为80.18%。煅烧工艺结果表明,升高温度和延长时间都能促使聚磷酸盐链的增长。在焙烧时间为1 h条件下焙烧温度从105℃逐渐升高到460℃,聚磷酸钙镁中磷的平均聚合度从1.00逐渐增加至3.23。其中,焙烧温度为340℃时,聚磷酸钙镁中磷的聚合率超过85%,但是聚合度还在增加。尽管肥料的水溶性随着聚磷酸盐链的增长而逐渐降低,但是当焙烧温度≤340℃时有效磷含量依然大于90%(质量分数)。在340℃焙烧1.0~2.0 h后发现,当焙烧时间为1.0 h时,聚磷酸钙镁中磷的聚合率和平均聚合度分别达到87.4%和2.80。通过工艺条件优化,可在聚合度分布水平上实现聚磷酸盐的可控制备,这也开辟了一种构建缓释肥的新方向。在340℃聚合1.0 h优选出聚合度为1~10分布的聚磷酸钙镁,表现为多孔的非晶态结构,其中有效磷、钙、镁养分含量超过85%(质量分数),可作为一种新型的多元缓释肥。In view of the intractable use of wet-process phosphoric-acid slag and phosphate tailing,a strategy was proposed for preparing calcium magnesium polyphosphate fertilizer via calcining wet-process phosphoric-acid slag and phosphate tailing composites.Based on the decomposition ratio of phosphate tailing,the suitable mass ratio of phosphate tailing and wetprocess phosphoric-acid slag was 0.30,and the decomposition ratio was 80.18%.The results of calcination process showed that both increasing temperature and prolonging time promoted the growth of polyphosphate chain.The average-degree of polymerization was increased from 1.00 to 3.23 after calcinating at 105~460℃for 1.0 h.Among them,at 340℃the polymerization rate reached 85%,but the polymerization degree was still increasing.Although the water solubility of fertilizer decreased gradually with the increase of polymerization chain,the available phosphorus content was still more than 90%when the temperature did not exceed 340℃.After calcination at 340℃for 1.0~2.0 h,it was found that when calcination time was1.0 h,the polymerization rate and average degree of polymerization reached 87.4%and 2.80,respectively.Optimizing the processing parameters,the polycondensation could be controlled on the level of polymerization degree distribution,which opened a new direction for the construction of slow-release fertilizer.Polyphosphate containing species with polymerization degree from 1 to 10 could be optimized under the calcination of 340℃for 1.0 h,which resulted with amorphous and porous-structure.The available phosphorus,calcium and magnesium were over 85%(mass fraction),which could be used as a new multi-element slow-release fertilizer.

关 键 词：磷酸渣 磷尾矿 聚磷酸钙镁 聚合度 资源化利用 

分 类 号：TQ442.33[化学工程—化学肥料工业]