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介绍湿法浓磷酸自动反洗表面过滤净化装置的工作原理及具体的操作工艺,确定浓磷酸自动反洗表面过滤净化的最佳工艺条件为:过滤压力小于0.02 MPa,反冲周期12 min,反冲时间10 s,清洗周期18 h,稀硫酸溶液清洗时间1.5 h,清洗液w(H_2SO_4)12%,清洗液温度80℃,氢氧化钠溶液清洗时间1.5 h,清洗液w(NaOH)15%,清洗液温度70℃,同时清洗过程辅以蒸汽加热及压缩空气曝气。该工艺条件下,浓磷酸w(固)由4.5%降至0.8%以下,减少浓磷酸储罐投用量近1/4,缩短浓磷酸陈化周期近30%,减少带入磷复肥生产系统中的杂质沉淀量约为30 000 t/a,有效提高浓磷酸品质,稳定磷复肥产品质量。
The working principle and specific operation technology of wet concentrated phosphoric acid automatic backwashing surface filtration and purification device are introduced. The optimum technological conditions for the filtration and purification of concentrated phosphoric acid automatic backwashing are as follows: the filtration pressure is less than 0.02 MPa, the recoil period is 12 min, the reverse The cleaning time is 10s, the cleaning time is 18h, the dilute sulfuric acid solution cleaning time is 1.5h, the cleaning solution w (H_2SO_4) is 12%, the cleaning solution temperature is 80 ℃, the sodium hydroxide solution cleaning time is 1.5 h, , Cleaning fluid temperature 70 ℃, while cleaning process assisted by steam heating and compressed air aeration. The process conditions, concentrated phosphoric acid w (solid) from 4.5% down to 0.8% or less, reducing the dosage of concentrated phosphoric acid storage tank nearly 1/4, shortening the phosphoric acid aging cycle nearly 30%, reduced into the phosphate compound production system The amount of impurities in the precipitate is about 30 000 t / a, effectively improve the quality of concentrated phosphoric acid and stabilize the quality of phosphate compound products.