长江科学院院报 ›› 2019, Vol. 36 ›› Issue (3): 13-18.DOI: 10.11988/ckyyb.20170981

• 水资源与环境 • 上一篇    下一篇

镁矿渣酸溶释出镁离子的特征及影响因素研究

黎睿1,2, 汤显强1,2   

  1. 1.长江科学院 流域水环境研究所,武汉 430010;
    2.长江科学院 流域水资源与生态环境科学湖北省重点实验室,武汉 430010
  • 收稿日期:2017-08-23 出版日期:2019-03-01 发布日期:2019-03-20
  • 通讯作者: 汤显强(1981-),男,湖北竹溪人,教授级高级工程师,博士,主要从事水资源保护与水污染控制研究。E-mail: ckyshj@126.com
  • 作者简介:黎 睿(1990-),男,湖北竹溪人,工程师,硕士,主要从事富营养化水体修复技术研究。E-mail: Leeruiwh@outlook.com
  • 基金资助:
    国家自然科学基金项目(51379017)

Magnesium Extraction from Magnesite Tailings by Acid Leaching: Characteristics and Influential Factors

LI Rui1,2, TANG Xian-qiang1,2   

  1. 1.Basin Water Environment Department, Yangtze River Scientific Research Institute, Wuhan 430010, China;
    2.Hubei Provincial Key Laboratory of Basin Water Resource and Eco-environmental Science, Yangtze River Scientific Research Institute, Wuhan 430010, China
  • Received:2017-08-23 Online:2019-03-01 Published:2019-03-20

摘要: 为评估镁矿渣用于人工湿地填料回收磷的潜力,分析了镁矿渣酸溶释出镁离子的特征及影响因素。结果表明:当镁矿渣颗粒直径 <150 μm(100目)时,颗粒浓度为5 g/L时,随着浸出时间的延长,浸出液中镁离子浓度逐渐增加,浸提5 h后镁矿渣中镁离子达到浸出平衡,浸出量不再发生变化;浸出溶液中镁离子的浓度随着浸提液中盐酸浓度的降低而逐渐下降。当镁矿渣颗粒直径 <150 μm时,盐酸浓度为1 mol/L,浸出时间为5 h时,增大浸出液中镁矿渣浓度,镁离子的浸提效率反而降低。当浸提盐酸浓度为1 mol/L,浸出液中镁矿渣浓度为5 g/L时,镁离子的浸出量达到最大值,为117.70 mg/kg。通过对比浸出前后镁矿渣中镁形态发现,在最佳浸提条件下,浸出的镁几乎全部为酸可溶态(占比达92.00%)。浸提后镁矿渣粒径减小,比表面积增大,其矿物晶格受到破坏,对溶液中的磷吸附能力得到强化。理论上对污水中磷的去除能力可达810 mg/kg,是一种极具潜力的磷回收材料。

关键词: 镁矿渣, 镁离子, 盐酸浸提, 磷回收, 释放动力学, 人工湿地

Abstract: In an attempt to evaluate the potential of using magnesite slag as a solid magnesium source for the recovery of phosphorus in constructed wetland, we investigated the characteristics and influencing factors of magnesium extraction from magnesite slag by HCl leaching. Results revealed that when the particle size of magnesite slag was less than 150 μm and the particle concentration was 5 g/L, the concentration of magnesium ion in leaching solution increased gradually with the prolongation of leaching time until equilibrium was reached five hours later. With the decline of hydrochloric acid concentration in the leaching solution, the concentration of magnesium ion decreased correspondingly. However, when magnesite slag (particle size < 150 μm) was soaked in hydrochloric acid solution (concentration 1 mol/L) for five hours, increasing the magnesite slag concentration would reduce the extraction efficiency. The extraction of magnesium reached maximum (117.70 mg/kg) when hydrochloric acid concentration was 1 mol/L and magnesite slag concentration was 5 g/L. Under such optimal extraction condition, the extracted magnesium was almost acid soluble, accounting for 92% of the total extracted amount. After leaching, magnesite slag’s ability of adsorbing phosphorus in solution was improved as the mineral lattice was destroyed, and the particle size of magnesium slag decreased while the specific surface area increased. In theoretical sense, the magnesium ions in the leaching solution could recover 810 mg phosphorus per kilogram of magnesium slag, indicating that magnesite slag has good potential in phosphorus recovery.

Key words: magnesium mineral residue, magnesium ion, HCl soaking, phosphorus recovery, release kinetics, constructed wetland

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