白肥中磷的回收利用及酸解动力学研究

发布时间：2018-02-25 21:23

  本文关键词： 湿法磷酸 白肥 硫酸 磷酸一铵 浸取动力学　出处：《华东理工大学》2015年硕士论文　论文类型：学位论文

【摘要】：白肥是湿法磷酸三段(或两段)中和法生产饲料级磷酸氢钙时,一段中和阶段得到的固体产物。白肥中P205含量约20-35%,同时富集了湿法磷酸中大部分的Fe、Al、F以及重金属等杂质。白肥中的磷占原料湿法磷酸中总磷的15-30%,但大量杂质的富集限制了其应用范围。白肥的存在,大大制约了饲料级磷酸氢钙产业的发展。为白肥寻找更有效的利用途径,对磷化工行业有重要的实际意义。本文以四川某磷化工企业饲料级磷酸氢钙工艺中产生的白肥为原料,对其产生过程和组成进行了分析,并根据其特点,提出了一条以白肥为磷源生产一等品肥料级磷酸一铵的工艺方法：控制适宜的条件,用稀硫酸浸取白肥中的磷；浸取酸与稀磷酸按一定的配比混合后,进行脱氟处理；脱氟后的混合磷酸与液氨反应,通过控制pH值得到磷酸一铵料浆；料浆经干燥后即得合格的一等品磷铵。实验考察了稀酸浸取回收白肥中P205工艺过程,当以最大限度回收白肥中P为目的时,硫酸浸取白肥的最佳条件为：H2SO4/P2O5 (mol)=1.5-1.6,浸取温度为40～45℃,硫酸浓度为7～8%,白肥粒度小于200目,P的浸取浸取率可达到92%以上；但同时白肥中80%的Al,70%的F以及90%以上的Fe也被浸取。通过控制浸取剂的用量等条件,可以显著改善浸取的选择性。当H2SO4/P2O5 (mol)=0.8-1.0时,可以回收70%以上的P；同时白肥中约40%的Fe、Al以及35%左右的F被浸取。浸取的选择性和磷的浸取率有一定的矛盾,需要根据具体的工艺需要选择合适的浸取条件。在浸取工艺研究的基础上,本文考察了白肥浸取的动力学特性。针对高P浸取率时的浸取反应,建立了浸取动力学数学模型。
[Abstract]:White fertilizer is used to produce feed-grade calcium hydrogen phosphate by three-stage (or two-stage) wet phosphoric acid neutralization. The content of P205 in white fertilizer is about 20-35, and it has enriched most of the impurities in wet phosphoric acid, such as heavy metal and so on. Phosphorus in white fertilizer accounts for 15-30% of total phosphorus in raw material wet phosphoric acid, but a large amount of impurity is rich. Set limits its scope of application. The existence of white fertilizer, The development of feed grade calcium hydrogen phosphate industry is greatly restricted. It is of great practical significance for the phosphorus chemical industry to find a more effective utilization way for white fertilizer. In this paper, the white fertilizer produced in feed grade calcium hydrogen phosphate process of a phosphorous chemical enterprise in Sichuan is used as raw material. The production process and composition were analyzed. According to its characteristics, a technological method of producing first grade fertilizer grade ammonium phosphate with white fertilizer as phosphorus source was put forward: controlling suitable conditions and leaching phosphorus in white fertilizer with dilute sulfuric acid; After leaching acid and dilute phosphoric acid were mixed according to a certain proportion, the defluorination treatment was carried out, and the mixed phosphoric acid after defluorination reacted with liquid ammonia, which was worth to the monoammonium phosphate slurry by controlling pH. The process of recovering P205 from white fertilizer by dilute acid leaching was investigated. When the maximum recovery of P from white fertilizer was used as the purpose, the optimum conditions for leaching white fertilizer with sulfuric acid were as follows: 1. 5-1. 6% H _ 2SO _ 4 / P _ 2O _ 5 / P _ 2O _ 5, and the leaching temperature was 4045 鈩，

本文编号：1535196