【作者】 唐盛伟；

【导师】 梁斌； 杨宗伟；

【作者基本信息】 四川大学 ， 化学工程， 2002， 硕士

【摘要】 分别用湿法工业磷酸（19.41％P₂O₅）和纯稀磷酸（23.68％P₂O₅）与气氨中和并进行浓缩得到一系列不同中和度、不同含水率的酸性磷铵料浆。研究了料浆的密度、沸点、导热系数、氟逸出率与中和度、含水率的关系。所得结果为酸性磷铵料浆浓缩法制磷铵提供了重要的基础数据。 研究结果表明，料浆的密度随含水率的减小、中和度的减小而增加，可通过对密度进行预测。料浆的沸点随着含水率的减小、中和度的减小而升高。含水率低于40％时，沸点随含水率的变化更显著。在实验范围内，可通对沸点进行预测。 氟逸出率随含水率的减小、中和度的减小而增大。中和度低于0.4时，氟逸出率明显较大，受中和度的影响也非常显著，当中和度超过0.6之后，氟逸出率变化很小。 料浆导热系数的范围为0.434～0.630 w／m℃。无固体颗粒析出时，料浆导热系数随含水率和中和度的减小而减小，随温度升高而增大。当有固体颗粒析出时，料浆导热系数随含水率减小而增大。湿法磷酸料浆的导热系数比纯稀磷酸料浆的导热系数略小。 用酸性磷铵料浆进行工业浓缩实验，结果表明，可以在现有的料浆法浓缩系统中通过局部整改进行酸性磷铵料浆的浓缩。对生产过程和工艺条件进行分析表明，将中和度0.4～0.5酸性料浆浓缩至含水率20％左右，再进行第二次氨中和及喷浆造粒，可以有效地利用二次中和热，简化磷铵生产流程，降低能耗。更多还原

【Abstract】 Ammonium phosphate is an important compound fertilizer. It is a new way to produce ammonium phosphate by concentrating acidic ammonium phosphate slurry. The dependence of the density,thermal conductivity,boiling point of the acidic ammonium phosphate slurry on both neutralization degree and water content is very important to the industrial realization of the new process.The acidic ammonium phosphate slurries with different neutralization degrees were obtained by neutralizing dilute pure phosphoric acid (P2O523.68%) or wet process phosphoric acid (P2O5l9.41%) with ammonium. They were concentrated to different water contents. The dependence of the density boiling point fluorine volatility and thermal conductivity on neutralization degree and water content were measured.The results indicate that the density of slurry increases with the reduction of water content and/or neutralization degree. The density of the slurry from wet process phosphoric acid is slightly higher than that from dilute pure phosphoric acid. The density of acidic ammonium phosphate slurry can be calculated by the equation p = k(psxv+pL(l-xv)).The experiments shows that the boiling point of slurry rises with the reduction of water content and/or neutralization degree. When water content is below 40%,the boiling point strongly depends on the water content. The boilingpoint can be calculated by equation T = Tb+Tb.The fluorine volatilizes in the concentration of the slurries from wet process phosphoric acid. The volatilization was enhanced in low water content and low neutralization degree range. When the neutralization degree is below 0.4,the fluorine volatility sharply increases with decreasing neutralization degree. While,at a neutralization degree over 0.6,the volatility drops to a very low level.The experiments also show that the thermal conductivity ranged from 0.434 to 0.630 w/m. When no crystalline exist in solution,the thermal conductivity increases with increasing temperature,water content or neutralization degree. However,when crystalline appears,it increases with decreasing water content. The thermal conductivity of the slurries from wet process phosphoric acid is slightly less than that of the slurries from dilute pure phosphoric acid.An industry test for the concentration of acidic ammonium phosphate slurry was conducted in an existing modified concentrating system. According to the test results and process parameters,acidic ammonium phosphate slurry with a neutralization degree of 0.4-0.5 can be directing concentrated to water content 20%. It is further neutralized by ammonia to produce ammonium phosphate. The secondary neutralization releases a large amount of heat which can be used to vaporize water. It will be a simply energy saving process.更多还原