Chemical Industry and Engineering Progress ›› 2021, Vol. 40 ›› Issue (7): 4011-4020.DOI: 10.16085/j.issn.1000-6613.2020-1529

• Resources and environmental engineering • Previous Articles     Next Articles

Extraction of aluminum and iron from coal gangue by low temperature neutralization-pressure acid leaching

LI Haolin(), ZENG Dehui, ZHENG Guangya, XIA Jupei()   

  1. Faculty of Chemical Engineering, Kunming University of Science and Technology, Kunming 650500, Yunnan, China
  • Received:2020-08-03 Revised:2020-11-20 Online:2021-07-19 Published:2021-07-06
  • Contact: XIA Jupei

低温中和-加压酸浸提取煤矸石中铝铁

李浩林(), 曾德恢, 郑光亚, 夏举佩()   

  1. 昆明理工大学化学工程学院,云南 昆明 650500
  • 通讯作者: 夏举佩
  • 作者简介:李浩林(1995—),男,硕士研究生,研究方向为固体废弃物共伴生资源利用。E-mail:lhl951102@qq.com
  • 基金资助:
    国家自然科学基金(21566018)

Abstract:

In order to solve the problems of high acid consumption, low acid utilization rate and the difficulty in separating aluminum and iron during their industrial extraction from coal gangue(CG), low-temperature neutralization-pressure acid leaching is adopted for the first time to achieve high-efficient extraction of aluminum and iron from the CG from Panzhou, Guizhou province. The optimal process conditions for the room temperature neutralization process are as follow: the acid is 20% of the theoretical consumption, the leaching time is 120min, and the mass ratio of sulfuric acid solution to solid is 3∶1. With the neutralized slag as raw material, the optimal process conditions for the pressurized acid leaching process are as follow: leaching time of 120min, leaching temperature of 150℃, and the mass ratio of sulfuric acid solution to solid of 3.5∶1 with the theoretical acid consumption of CG. Under the aforementioned conditions, the leaching rates of aluminum and iron were 95.77%, 98.37% respectively, and the contents of silicon and titanium in acid residue ash were 90.2%, 9.18% respectively. The fresh coal gangue was neutralized with the recycled acid leaching solution, yielding the concentrations of aluminum and iron in the extract solution of 62.20g/L, 57.95g/L respectively. Compared with the conventional acid leaching process, the acid consumption by the two-step process is lower, and the acid utilization efficiency is higher. Through the characterizations of the CG and slag by X-ray diffractometer (XRD), Fourier infrared spectrometer (FTIR) and Scanning electron microscope (SEM), the mechanism of carbonic acid leaching process in gangue was preliminarily analyzed. This work provides a new route and theoretical support for the industrial extraction of aluminum and iron from CG.

Key words: coal gangue, neutralization, pressure acid leaching, aluminum, iron

摘要:

以贵州盘县煤矸石为研究对象,为解决其工业生产提取铝铁时酸耗量大、酸利用率低及后续铝铁产品分离困难等问题,根据其矿物组成特点,本文首次采用低温中和-加压酸浸工艺对铝铁提取进行了详细研究。室温下中和最优工艺条件为20%理论酸耗、浸出时间120min、液固比3∶1(硫酸溶液与固体的质量比,以g/g计);以中和渣为原料,煤矸石理论酸耗为基础,加压酸浸最优工艺条件为浸出时间120min、浸出温度150℃、液固比3.5∶1(硫酸溶液与固体的质量比,以g/g计)。在此条件下,氧化铁浸出率为98.37%,氧化铝浸出率为95.77%,酸浸渣灰分中氧化硅质量分数为90.2%,氧化钛质量分数为9.18%。以最优工艺条件下的酸浸液循环中和新鲜煤矸石,得到的铝铁提取液中氧化铁浓度为57.95g/L,氧化铝浓度为62.20g/L。相比常规酸浸工艺具有酸耗低、酸利用率高等优点。借助X射线衍射仪(XRD)、傅里叶红外光谱仪(FTIR)和扫描电子显微镜(SEM)等分析手段,初步对两步溶出过程进行了机理分析,为煤矸石工业生产提取铝铁提供了新路线和理论支撑。

关键词: 煤矸石, 中和, 加压酸浸, 铝,

CLC Number: 

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