无机材料学报

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焙烧-碱浸-吸附耦合强化粉煤灰高效提锂

黄起焓1,2, 刘畅1,2, 郝佳瑜1,2,3,4, 李治华1,2,3,4, 徐文华1,2,3,4   

  1. 1.郑州大学 材料科学与工程学院,郑州 450001;
    2.郑州大学 中原关键金属实验室,郑州 450001;
    3.关键金属选冶与高纯制程全国重点实验室,郑州 450001;
    4.关键金属矿产超常富集提取教育部重点实验室,郑州 450001
  • 收稿日期:2025-11-26 修回日期:2026-02-15
  • 作者简介:黄起焓(2001-), 女, 硕士研究生. E-mail: 15937751770@163.com
  • 基金资助:
    河南省科技研发计划联合基金 (242301420043); 国家自然科学基金(52404367); 中原关键金属实验室“高峰”攀登科技计划优秀青年科学家项目(GJJSGFYQ202423)

Integrated Roasting-Alkali Leaching-Adsorption Strategy for Highly Efficient Lithium Extraction from Coal Fly Ash

HUANG Qihan1,2, LIU Chang1,2, HAO Jiayu1,2,3,4, LI Zhihua1,2,3,4, XU Wenhua1,2,3,4   

  1. 1. School of Materials Science and Engineering, Zhengzhou University, Zhengzhou 450001, China;
    2. Zhongyuan Critical Metals Laboratory, Zhengzhou University, Zhengzhou 450001, China;
    3. State Key Laboratory of Critical Metals Beneficiation, Metallurgy and Purification, Zhengzhou 450001, China;
    4. The Key Lab of Critical Metals Minerals Supernormal Enrichment and Extraction, Ministry of Education, Zhengzhou 450001, China
  • Received:2025-11-26 Revised:2026-02-15
  • About author:HUANG Qihan (2001-), female, Master candidate. E-mail: 15937751770@163.com
  • Supported by:
    Natural Science Foundation of Henan Province (242301420043); National Natural Science Foundation of China (52404367)

摘要: 我国粉煤灰富含锂且年产量大,对其进行开发利用对保障新能源产业可持续发展意义重大。然而,粉煤灰中的锂品位较低,且主要赋存于化学性质稳定的玻璃相中,传统方法难以高效、选择性提取。针对这一技术瓶颈,本研究提出一种集“活化焙烧-温和碱浸-吸附分离”于一体的多级提锂新策略。首先,将粉煤灰与硫酸钠混合,在900 ℃下焙烧2 h,有效破坏玻璃相中的Si-O-Al键,使晶格重构,实现了锂及其载体矿物的热活化转型。随后,焙砂再经温和碱浸(1 mol·L-1 NaOH、70 ℃、液固比5 : 1)选择性释放锂离子。最后,利用对锂具有特殊记忆效应的钛酸锂离子筛进行吸附,实现了锂与杂质的高效特异性分离。新工艺的总锂回收率(Rtotal)达73.20%,αLi/M分离系数超96,所得净化液经富集后可直接制得纯度为99.02%的磷酸锂产品,实现了粉煤灰锂资源的精准提纯。本研究为我国巨量粉煤灰的高值化利用及非常规锂资源的开发提供了一条绿色、高效的新思路,具有重要的工业应用前景。

关键词: 粉煤灰, 活化焙烧, 温和碱浸, 钛基吸附, 选择性提锂

Abstract: Since a vast amount of coal fly ash (CFA) with rich lithium was produced domestically each year, the extraction of this resource is of great importance for supporting the sustainable development of the new energy. However, conventional methods for lithium extraction from CFA are constrained by efficiency and selectivity, owing to the low grade of lithium and its encapsulation within a chemically stable glass phase. To overcome this technical bottleneck, this study proposes a novel multi-stage lithium extraction strategy integrating "activation roasting-mild alkaline leaching-adsorption separation." First, CFA was mixed with sodium sulfate and roasted at 900 ℃ for 2 h. This high-temperature roasting effectively disrupted the Si-O-Al bonds within the glass phase, inducing lattice reconstruction and enabling the thermal activation of lithium and its host minerals. Subsequently, the calcine underwent mild alkaline leaching (1 mol·L-1 NaOH, 70 ℃, liquid-to-solid ratio of 5 : 1) to achieve the selective release of lithium ions. Finally, a lithium titanate ion sieve, known for its specific memory effect towards lithium, was employed for adsorption, accomplishing the highly efficient and specific separation of lithium from impurities. The new process achieved a total lithium recovery of 73.20% and a lithium/impurity separation factor exceeding 96. The purified solution can be concentrated to directly produce lithium phosphate with a purity of 99.02%, enabling the precise purification of lithium from CFA. This work provides a potential green and efficient approach for the high-value utilization of China's vast CFA reserves and the development of unconventional lithium resources.

Key words: coal fly ash, activation roasting, mild alkaline leaching, titanium-based adsorbent, selective lithium extraction

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