无机盐工业
主管:中海油天津化工研究设计院有限公司
主办:中海油天津化工研究设计院有限公司
   中海油炼油化工科学研究院(北京)有限公司
   中国化工学会无机酸碱盐专业委员会
ISSN 1006-4990 CN 12-1069/TQ

无机盐工业 ›› 2024, Vol. 56 ›› Issue (1): 107-113.doi: 10.19964/j.issn.1006-4990.2023-0149

• 环境·健康·安全 • 上一篇    下一篇

硫酸直接浸出磷石膏中稀土元素的研究

夏桂英1(), 杨柳春1(), 袁治冶2   

  1. 1.湘潭大学环境与资源学院,湖南 湘潭 411105
    2.湘潭电化科技股份有限公司,湖南 湘潭 411201
  • 收稿日期:2023-03-20 出版日期:2024-01-10 发布日期:2024-01-18
  • 通讯作者: 杨柳春(1978— ),男,博士,副教授,主要研究方向为工业副产石膏资源化;E-mail:yangliuchun@xtu.edu.cn
  • 作者简介:夏桂英(1999— ),女,硕士,主要研究方向为磷石膏中有价元素的提取;E-mail:2545422563@qq.com

Study on direct leaching of rare earth elements from phosphogypsum with sulfuric acid

XIA Guiying1(), YANG Liuchun1(), YUAN Zhiye2   

  1. 1. College of Environment and Resources,Xiangtan University,Xiangtan 411105,China
    2. Xiangtan Electrochemical Scientific Co.,Ltd.,Xiangtan 411201,China
  • Received:2023-03-20 Published:2024-01-10 Online:2024-01-18

摘要:

为弄清磷石膏(PG)中低含量稀土元素(REE)的浸出规律及磷石膏浸出后品质的改善情况,通过实验研究了用硫酸直接浸出磷石膏中REE的过程动力学及磷石膏物相的变化。研究结果发现,REE浸出率随浸出温度升高先降低后增加、随液固比增大不断增加、随硫酸浓度增大先增加后降低。在25 ℃下总浸出率较高,可达25%;其中La的浸出率最高,Pr的浸出率最低。REE浸出率在0~20 min内快速增加,随后趋于平缓,整个浸出过程动力学受灰层扩散控制。伴随着REE浸出的同时,石膏表面发生溶解,在溶液过饱和时重结晶形成脱水相的针状CaSO4细晶,而石膏的体相整体形貌变化较小,导致REE浸出率偏低。酸浸后样品粒径小于10 μm的颗粒占14.90%,较原样增加了5.16%,磷石膏粒径变小、杂质减少。研究结果可为磷石膏的综合利用提供参考。

关键词: 磷石膏, 稀土元素, 硫酸浸出, 石膏物相

Abstract:

In order to comprehend the leaching rule of phosphogypsum(PG) with low rare earth element(REE) content and the improvement of phosphogypsum quality after leaching,the process kinetics of direct leaching of REE from PG with sulfuric acid and the changes of PG phase were studied.The results showed that the leaching rate of REE was initially decreased and then increased with the elevating of leaching temperature,enhanced along with liquid-solid ratio,and firstly increased and then decreased with the rising of acid concentration.The total leaching rate could be achieved up to 25% at 25 ℃,with the leaching rate of La as the highest and that of Pr as the lowest.The REE leaching rate was increased rapidly in 0~20 min and then leveled off.The kinetics of the whole leaching process was controlled by ash layer diffusion.The surface of gypsum was dissolved during the leaching,and then recrystallized into acicular CaSO4 particles of dehydrated phase after the solution was saturated.However,the overall morphology of gypsum bulk phase changed little,resulting in a low REE leaching rate.Moreover,the fraction of the PG with a particle size less than 10 μm was 14.90%,increased by 5.16% compared with the original sample.The particle size of PG after acid leaching was smaller and the impurities were reduced.The results could provide reference for comprehensive utilization of phosphogypsum.

Key words: phosphogypsum, rare earth elements, sulfuric acid leaching, gypsum phase

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