镁盐浸取风化壳淋积型稀土矿浸出过程动力学研究

Leaching Kinetics of Weathered Crust Elution-Deposited Rare Earth Ore with Magnesium Salt

为提高以镁盐为浸取剂浸取稀土时的稀土浸取率,对镁盐浸取风化壳淋积型稀土矿时浸出过程动力学进行研究。结果表明:镁盐浸取风化壳淋积型稀土矿中稀土和铝的反应过程符合内扩散控制动力学模型;不同镁盐浸取稀土和铝过程中离子交换反应的反应活化能及反应级数从小到大依次为硝酸镁<氯化镁<硫酸镁;以硝酸镁为浸取剂时浸取反应速率快,达到反应平衡所需时间短,工业上可采用硝酸镁作为浸取剂在缩短反应时间、降低镁盐浓度的条件下,有效降低成本,优化浸出过程;镁离子浓度对稀土浸取的影响要大于其对铝浸取的影响,镁盐与稀土反应的反应活化能及反应级数均小于其与铝反应的反应活化能及反应级数;铝浸取过程达到平衡所需的时间均大于以相同浸取剂浸取稀土时浸取过程达到平衡所需的时间,铝的浸出速率要略慢于稀土,在工业生产中可以对稀土浸出液进行分批收液,达到有效降低稀土浸出液中铝含量的目的。

In order to improve the leaching rate of rare earth minerals with magnesium salt as the leaching agent,the leaching kinetics of weathered crust elution-deposited rare earth ore by magnesium salt as leaching agent was studied. The results show that the reaction process of magnesium salt leaching weathering crust elution-deposited rare earth ore meet with shrinking-core dynamical model,The activation energy and reaction series of ion exchange reaction follows the orders： magnesium nitrate magnesium chloride magnesium sulfate. When magnesium nitrate is used as the leaching agent,the reaction rate is fast and the reaction time to the equilibrium state is short. Under the condition of shortening the reaction time and reducing the concentration of magnesium salt,the leaching process can be effectively optimized when magnesium nitrate is used in the industry. And the effect of magnesium ion concentration on the leaching of rare earth is greater than that on the leaching of aluminum,the activation energy and reaction series of ion exchange reaction on rare earth is smaller than on aluminum;the time required for the aluminum leaching process to equilibrium state is longer than that needed for rare earth leaching. The aluminum leaching rate is slightly slower than that of the rare earth. The rare earth leachate can be collected in batches to reduce the content of aluminum in leaching agent during industrial production.