自然氧化预处理钕铁硼废料浸出过程

NdFeB magnet scrap pretreated by air oxidation and its leaching process

  • 摘要: 为降低钕铁硼废料预处理成本,探讨利用盐酸润湿-空气自然氧化法对钕铁硼废料进行预处理,并对经盐酸润湿-空气自然氧化处理的钕铁硼废料中稀土的浸出工艺和浸出动力学进行研究.结果表明:以4 mol/L HCl润湿原料,在空气中放置20 d后铁的氧化率达到92.37 %,可满足铁硼废料中稀土回收的前期处理工艺要求,降低生产成本;在浸出的过程中,当反应温度为363 K,盐酸浓度为2 mol/L、粒度为0.055~0.088 mm、液固比VL/WS=8:1、搅拌速率500 r/min下,反应时间为60 min后经盐酸润湿-空气自然氧化Nd-Fe-B废料中稀土的浸出率可达89.36 %;研究表明,钕铁硼废料中稀土浸出过程主要是受扩散控制,其表观化学反应活化能E=17.49 kJ/mol.

     

    Abstract: This paper studied the NdFeB pretreatment with hydrochloric acid wetting and air oxidation to reduce the pretreatment cost of NdFeB scrap, and investigated the rare earth leaching process and leaching kinetics from NdFeB scrap by hydrochloric acid. The results show that the oxidation rate of iron in NdFeB scrap is up to 92.37 % after wetting with 4 mol/L HCl and staying for 20 days in the air, which can meet the requirements of iron oxidation in the rare earth recovery and reduce the production cost; in the leaching process, when the reaction temperature is 363 k, the hydrochloric acid concentration is 2 mol/L, the particle size is of 0.055 mm to 0.088 mm, the ratio of VL/WS is 8:1, and the stirring speed is 500 r/min, the rare earth leaching rate from NdFeB scrap can reach 89.36 % after leaching for 60 mins. Studies also show that the rare earth leaching process from NdFeB scrap is followed the unreacted shrinking core model controlled by diffusion, and its apparent reaction activation energy is 17.49 kJ/mol.

     

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