因湿法浓磷酸黏度大、细粒级悬浮物多，难以快速沉降，导致磷化工产品加工生产效率低。研究脱氟剂种类、脱氟温度、压力、时间对湿法浓磷酸氟含量及沉降的影响。实验表明，在脱氟剂为白炭黑，真空度为0.08 MPa、反应温度为85 ℃、反应时间为2.0 h时，湿法浓磷酸氟质量分数仅为0.38%，沉降时间远低于其他沉降技术。沉降时间与氟含量呈正相关，氟含量越低，湿法浓磷酸沉降时间越短。通过X射线光电子能谱仪（XPS）、X射线衍射仪（XRD）、扫描电子显微镜（SEM）等表征手段分析湿法浓磷酸脱氟前后的沉降物。结果表明：影响沉降速率的主要原因是溶液中细粒级CaSO₄·2H₂O难以沉降，在一定温度压力下细粒级CaSO₄·2H₂O再结晶，粒径增大，易于沉降；其次，浓缩升温导致湿法浓磷酸中金属阳离子与氟离子络合键被打破，络合物溶解，破坏胶体稳定性，氟从体系逸出，同时释放的金属离子在体系中形成新物质引发固相颗粒团聚，进一步增大固相颗粒尺寸与密度，从而加快湿法浓磷酸沉降。该研究结果为湿法浓磷酸快速沉降提供了新方法。

The viscosity of wet process concentrated phosphoric acid is high，and it is difficult for fine-grained suspended solids to settle quickly，which reduces the processing and production efficiency of phosphorus chemical products.In this paper，the effects of defluorination agent type，defluorination temperature，pressure and time on the fluorine content and sedimentation of wet process concentrated phosphoric acid were studied.The results showed that the mass fraction of fluorine in wet concentrated phosphoric acid was only 0.38%，and the sedimentation time was much lower than that of other sedimentation technologies，when the defluorination agent was silica，the vacuum degree was 0.08 MPa，the reaction temperature was 85 ℃ and the reaction time was 2.0 h.The sedimentation time was positively correlated with the fluorine content.The lower the fluorine content，the shorter the sedimentation time of wet process concentrated phosphoric acid.The precipitates before and after defluorination of wet process concentrated phosphoric acid were analyzed by X-ray photoelectron spectroscopy（XPS），X-ray diffraction（XRD） and scanning electron microscopy（SEM）.The results showed that the main reason affecting the sedimentation rate was that the fine-grained CaSO₄·2H₂O in the solution was difficult to settle.Under a certain temperature and pressure，the fine-grained CaSO₄·2H₂O was recrystallized，the particle size was increased，and it was easy to settle.Secondly，the concentration and heating process disrupted the complexation bonds between metal cations and fluoride ions in wet process concentrated phosphoric acid，causing the solubility of the complex. It disrupted the colloid stability of the complex，causing fluoride to escape from the system.Simultaneously，the released metal ions formed new substances that induced the agglomeration of solid phase particles，further increasing the size and density of particles.Thereby the sedimentation of wet process concentrated phosphoric acid was accelerated.The results of this study provided a new method for the rapid sedimentation of wet process concentrated phosphoric acid.