Characterisation and magnetic separation of complex low grade saprolite ore for rare earth elements minerals recovery

IF 4.9 2区工程技术 Q1 ENGINEERING, CHEMICAL

Minerals Engineering Pub Date : 2025-05-28 DOI:10.1016/j.mineng.2025.109437

Theophilus Amos Judge , Richel Annan Dadzie , William Skinner , George Blankson Abaka-Wood

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Abstract

In this study, mineralogical and strategic magnetic beneficiation tests were undertaken on a complex low grade saprolite ore to assess the feasibility of recovering valuable rare earth elements (REE) minerals. Mineralogical characterisation tests revealed that bastnäsite was the main REE mineral, with significant amount of La-Nd-Si/Fe intergrowths. The bulk of the ore was occupied by clay and silicate minerals including mica, quartz, K-silicates, and Na-silicates. Subsequently, magnetic separation tests were conducted on the ore using a wet high intensity magnetic separator (WHIMS), where the relative effects of applied magnetic field intensity, matrix type, feed mass, feed desliming, and concentrate regrinding on REE minerals recovery were investigated. Experimental results showed that increasing magnetic field intensity and using fine expanded metal matrix enhanced REE minerals recovery, although concentrate grade was compromised. Additionally, different magnetic separation flowsheets employing regrinding and desliming stages were tested. The highest concentrate grade of 9.12 % total rare earth oxide (TREO) was achieved when the deslimed feed was processed at 1.7 T with the WHIMS fitted with the medium expanded metal matrix mesh, where 86 % REE recovery was observed. A beneficiation process flow sheet for recovering and upgrading REE minerals in the low-grade saprolite ore has been proposed, which recovered 74 % REE assaying a concentrate grade of 9.12% TREO . It was observed that the recovery of mica, entrainment recovery of liberated and unliberated silicate minerals and the presence of bastnäsite/REE-silicates intergrowths limited the extent of TREO upgrade that could be achieved although recoveries were high. The present study provides information on the process mineralogical data of the ore, whiles establishing the technical feasibility of employing magnetic preconcentration conditions to recover valuable REE minerals and identifying other preconcentration strategies which could be utilized in subsequent studies.

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稀土元素矿物回收中复杂低品位腐岩矿的表征及磁选

本文对某复杂低品位腐岩矿石进行了矿物学和战略磁选试验，以评价回收有价稀土矿物的可行性。矿物学特征测试表明：bastnäsite为主要的REE矿物，有大量的La-Nd-Si/Fe共生体。矿石的大部分为粘土和硅酸盐矿物，包括云母、石英、钾硅酸盐和钠硅酸盐。随后，利用湿式强磁选机对矿石进行了磁选试验，考察了外加磁场强度、基质类型、进料质量、进料脱泥、精矿再磨等因素对稀土矿物回收率的相对影响。实验结果表明，增大磁场强度和采用细膨胀金属基质可提高稀土矿物的回收率，但影响精矿品位。此外，还对采用再磨和脱泥阶段的不同磁选流程进行了试验。当脱泥料在1.7 T温度下，采用中膨胀金属基质网的WHIMS进行处理时，稀土精矿品位最高，总稀土氧化物（TREO）为9.12%，稀土回收率为86%。提出了一套低品位腐岩矿石中稀土元素回收升级的选矿工艺流程，该矿石稀土元素回收率为74%，精矿TREO品位为9.12%。观察到云母的回收、游离和未游离硅酸盐矿物的夹带回收以及bastnäsite/ ree -硅酸盐共生体的存在限制了TREO升级的程度，尽管回收率很高。本研究提供了矿石的工艺矿物学数据，同时确定了采用磁预选条件回收有价值稀土矿物的技术可行性，并确定了其他可用于后续研究的预选策略。

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来源期刊

Minerals Engineering 工程技术-工程：化工

CiteScore

8.70

自引率

18.80%

发文量

519

审稿时长

81 days

期刊介绍： The purpose of the journal is to provide for the rapid publication of topical papers featuring the latest developments in the allied fields of mineral processing and extractive metallurgy. Its wide ranging coverage of research and practical (operating) topics includes physical separation methods, such as comminution, flotation concentration and dewatering, chemical methods such as bio-, hydro-, and electro-metallurgy, analytical techniques, process control, simulation and instrumentation, and mineralogical aspects of processing. Environmental issues, particularly those pertaining to sustainable development, will also be strongly covered.