Abstract: This is to introduce a process for making diammonium phosphate fertilizer of 18-46 in which the raw materials used are dilute wet-process phosphoric acid and ammonia. The authors have studied the degree of neutralization of phosphoric acid with ammonia in relation to the ratio between N and P2O5 in product, the ratio between the liquid and solid phases in paste, the amount of water and ammonia evaporated from paste, etc.. At the same time, the authors have also studied the pelletizing and drying of the product, the recovery of dust from the tail gas, as well as the construction of various equipments. From their studies, they have found the following results. I. The optimum conditions for making diammonium phosphate fertilizer of 18-46 grade are as follows. a. The optimum concentration of phosphoric acid is 32% P2O5, b. the proper degree of neutralization of phosphoric acid with ammonia is at 1.78, and c. in pelletization, the recycling material which is 40% -6 to +12 mesh, 60% -12 mesh, and the quantity ratio is about 11 times of the product. II. They have also determined the construction and the materials for making the reactor, the pelletizer of horizontal type with double axis, the rotary dryer, and the scrubber of impingement type, etc..

摘要： 本文介绍以氨与未经浓缩的湿法磷酸为原料制取18—46磷酸铵肥料的工艺条件。 作者研究了磷酸和氨的中和度与肥料中氮磷比例,料浆的液固比,料浆中水分蒸发和氨的逸出等关系。同时研究了造粒过程、干燥炉带出气中粉尘的回收、成品干燥等工艺条件,以及设备构造。 作者认为最适宜的工艺条件是:磷酸浓度为P_2O_532％,磷酸与氨的中和度为1.78。造粒过程的返料粒度组成在-6+12目占40％、-12目占60％时,返料量为成品量的11倍左右。并确定了中和槽、卧式双轴造粒机、迴转干燥炉、冲击洗滌器等设备结构与材料。