脲硫酸分解磷矿过程第一阶段反应动力学研究

Reaction kinetics of the first stage in the process of urea sulfuric acid decomposing phosphorus rock

在反应温度333—358 K,硫酸质量分数29%—43%范围内,用纯试剂研究了尿素存在条件下硫酸分解磷矿过程第一阶段的反应速率,得到第一阶段反应活化能为9985 J/mol,反应级数为1.0309;与硫酸分解磷矿反应系统进行对照,对硫酸分解磷矿反应系统,反应活化能为9867 J/mol,反应级数为0.8218。影响反应速率的指前因子为k0,硫酸分解磷矿的k0值相当于脲硫酸分解磷矿的k0值的3.4倍。加入尿素后,第一阶段分解速率明显减慢。该研究较好地解释了脲硫酸分解磷矿工艺过程中磷矿分解率较高,硫酸钙包裹减轻、无需较长的堆置熟化期的问题,对于脲硫酸分解磷矿工艺条件的选择具有理论指导意义。

The effect of the urea addition on the first stage of sulfuric acid decomposing phosphorus rock （PR） was studied by using chemical pure agents with sulfuric acid mass fraction of 29% 43% and at 333-358 K. The reaction kinetics equations were obtained as follows： for urea sulfuric acid system, activation energy was 9 985 J/mol, reaction order was 1. 030 9; for sulfuric acid system, activation energy was 9 867 J/mol, reaction order was 0. 821 8, the pre-expotential factor k0 was 3.4 times of that of the urea sulfuric acid system. When urea was added in the sulfuric acid, reaction rate was slowed down. The features of high PR decomposing rate, less coating of CaSO4crystals and shorter disposal of the maturing period in the process of urea sulfuric acid decomposing phosphorus rock were well explained, which has great significance in choosing operating conditions when using urea sulfuric acid decomposing PR.