外源低分子有机酸对纯化磷酸铁铁中磷释放的影响

Effect of Exogenous Low Molecular Weight Organic Acids on the Release of Purified Iron Phosphate

运用高压溶液法对磷化渣进行3次提纯,获得高纯度的磷酸铁样品,采用扫描电子显微镜、X射线衍射仪对其进行表征。比较3种低分子有机酸(甲酸、乙酸、草酸)、混合酸及硫酸对纯化磷酸铁中水溶性磷释放的影响。研究结果表明,不同的低分子量有机酸对纯化磷酸铁具有不同的释放磷的能力,各有机酸对磷元素释放的作用依次表现为草酸>混合酸>甲酸≈乙酸;在5 g磷酸铁和500 m L去离子水的混合液中加入10 mmol的草酸时,水溶性总磷的析出效率最大。磷酸盐释放磷主要与有机酸的酸强度(pH)以及络合作用有关。

High-pressure solution method was used to purify phosphatizing residue three times to obtain high-purity iron phosphate samples. The samples were characterized by scanning electron microscopy and X-ray diffraction. The effects of three low molecular weight organic acids（formic acid, acetic acid, oxalic acid）, mixed acids and sulfuric acid on the release of purified iron phosphate were compared. The results showed that different types of low molecular weight organic acids had different ability to release phosphorus from purified iron phosphate. The effect of each organic acid on the release of phosphorus showed as follows： oxalic acid〉mixed acid 〉citric acid〉formic acid ≈ acetic acid;When 10 mmol of oxalic acid was added to a mixture of 5 g ferric phosphate and 500 mL deionized water, the precipitation efficiency of water-soluble total phosphorus was the highest. Phosphorus is mainly related to the acid strength（pH） of organic acids and complexation.