磷酸分解磷矿过程中金属元素的浸出规律研究

探究了以磷酸分解磷矿,关键酸解工艺参数对磷及Fe、Al、Mg、Pb、As浸出的影响规律,并从热力学角度进行了分析。结果表明,磷矿内磷及Fe、Al、Mg浸出率随磷酸质量分数、反应温度、反应时间和液固比的增大而增大,搅拌速度影响不明显;Pb浸出率随磷酸质量分数、反应温度和液固比的增大而增大,搅拌速度、反应时间影响不明显;As浸出率随反应温度升高呈先增大后减小趋势,随反应时间增加略有减小,磷酸质量分数、搅拌速度和液固比影响不明显。控制磷酸质量分数为30%（以P₂O₅计）、反应温度为80 ℃、搅拌速度为300 r/min、反应时间为150 min、液固质量比为10∶1,在此条件下,磷及Fe、Al、Mg、Pb、As的浸出率分别为98.65%、68.56%、48.54%、95.84%、32.85%和84.62%。通过热力学分析表明磷矿内Mg、As浸出率较高,Pb浸出率较低,而Fe、Al浸出率大小主要取决于磷矿中褐铁矿及高岭土含量。

Study on leaching law of metal elements in process of decomposing phosphate rock by phosphoric acid

By using phosphoric acid to decompose phosphate rock,the influence of key acid hydrolysis process parameters on the leaching of phosphorus,Fe,Al,Mg,Pb,and As was explored and it was analyzed from the perspective of thermodynamics. The results showed that the leaching rate of phosphorus,Fe,Al and Mg in phosphate rock increased with the increase of phosphoric acid concentration,reaction temperature,reaction time and liquid-solid ratio,and the effect of stirring speed was not obvious;The leaching rate of Pb increased with the increase of phosphoric acid concentration,reaction temperature and liquid-solid ratio,and the effect of stirring speed and reaction time was not obvious;As the increase of reaction temperature,the leaching rate of As firstly increased and then decreased,and slightly decreased with the increase of reaction time,the influence of phosphoric acid concentration,stirring speed and liquid-solid ratio was not obvious.Under the conditions of controlling phosphoric acid concentration of 30%P₂O₅,reaction temperature of 80 ℃,stirring speed of 300 r/min,reaction time of 150 min,and liquid-solid mass ratio of 10∶1,the leaching rates of phosphorus,Fe,Al,Mg,Pb,and as were 98.65%,68.56%,48.54%,95.84%,32.85%,and 84.62%,respectively.Thermodynamic analysis showed that the leaching rate of Mg and As in the phosphate rock was higher,and the leaching rate of Pb was lower,and the leaching rate of Fe and Al was mainly determined by the content of limonite and kaolin in the phosphate rock.