硝酸铵全溶造粒工艺条件的选择——生产15—15—15低氯复肥的又一途径

Selection of Process Conditions for Complete Dissolution and Granulation of Ammonium Nitrate-Another Way to Produce 15 - 15 - 15 Low-chlorine Compound Fertilizer

硝酸铵易吸湿、结块,不易破碎,高温下易发生爆炸,以其为氮素原料掺混的高浓度复肥颗粒不均匀、不致密,外观欠佳。根据硝酸铵的物化性质和在水中的溶解度随温度降低而显著下降等特性,采用高温饱和溶液溶解、低温稀释溶液喷浆的全溶造粒工艺,可制得15-15-15低氯三元复肥。全溶造粒的工艺条件是:控制硝酸铵在反应器中的温度为120℃,ω(NH_4NO_3)=95％;硝酸铵溶液的喷浆造粒温度75～80℃,ω(NH_4NO_3)=91.1％;干料进造粒机温度40～50℃。因硝酸铵在230℃时即发生急剧分解,故硝酸铵-磷酸铵体系肥料的干燥应在较低的物料温度和炉气温度下宜采用并流方式。

Ammonium nitrate is easy to absorb moisture and to cake, not easy to crush, and likely to explode at high temperature. Par deles of high-concentration compound fertilizer with ammonium nitrate as the source of nitrogen element are not homogeneous, not dense, and not good in appearance. Based on its chemical and physical properties as well as its characteristic that the dissolubility drops remarkably with the temperature drop,the complete dissolution and granulation process-including dissolving ammonium nitrate at relatively high temperature to the saturated solution and spraying low-temperature diluted solution-is used to produce 15 - 15 - 15 low-chlorine tertiary compound fertilizer The process conditions of complete dissolution and granulation are as follows: the temperature of ammonium nitrate in the reactor to be con- trolled at 120 ℃ ,w(NH4NO3)=95%;the temperature for spraying of ammonium nitrate solution and granulation 75 - 80 C .w(NH4NO3 ) 91. l%;the temperature of dry material fed to the granulator 40 -50 C . Because drastic decomposition will happen to ammonium nitrate at 230 ℃.fertilizers of the ammonium nitrate-ammonium phosphate system should he dried at relatively low temperature of material and furnace gas and in the concurrent process