高泥锂云母全粒级磁–浮联合选矿工艺

Study on the whole-grain magnetic–float combination beneficiation process of high mud lithium mica

  • 摘要: 我国南岭一带含有大量锂云母资源,其矿物组成复杂、细泥含量高,导致浮选分离困难、资源利用率低. 地球化学证实锂云母的演化大体呈现黑鳞云母→铁白云母→铁锂云母→锂多硅白云母→锂云母或类似的变化趋势,其中锂云母因含有铁元素而具有一定的弱磁性,超导磁选技术具有极大的潜力. 本文针对湖南界牌岭高泥锂云母资源,开展了全粒级的磁–浮联合分选新工艺研究,铁锂云母采用高梯度磁选优先分离富集,难选锂云母通过浮选预先富集,浮选精矿和细泥通过超导技术分离富集,形成了“高梯度磁选—脱萤石—锂云母浮选—超导磁选”的全粒级选矿工艺. 高泥锂云母矿石Li2O品位0.76%条件下,最终获得了Li2O品位为2.22%、回收率为77.62%的综合锂云母精矿. 新工艺通过高梯度磁选、超导磁选、浮选技术的有机结合,实现了高泥锂云母全粒级高效提取,为复杂锂云母矿的高效开发利用提供了借鉴.

     

    Abstract: The South China region is abundant in high mud lithium mica resources, which are characterized by their complex mineral composition and high fine mud content. These properties present significant challenges for flotation separation, resulting in low resource utilization rates. Geochemical studies have identified an evolutionary trend of lithium mica: Biotite evolving into Ferrimuscovite, then Zinnwaldite, Trilithionite, and finally Lithium mica. During this evolution, some lithium mica acquires weak magnetic properties owing to iron content, making it suitable for superconducting magnetic separation technology. This technology offers high magnetic field strength and low particle size limitations, offering great application prospects. This paper addresses the high mud lithium mica resource at Jiepailing, Hunan Province. The main lithium-bearing minerals in this ore are iron-bearing lithium mica, constituting 21.43% of the ore. Owing to the fine size of these target minerals, fine grinding is essential to increase monomer dissociation before beneficiation. The ore contains kaolinite and other vein minerals, which are easy to be muddied after grinding, making the amount of fine mud greatly increase. Additionally, the ore contains high amounts of fluorite, which negatively affects the flotation process for lithium mica concentration. The presence of high fluorite and fine mud content limits the efficacy of conventional flotation methods. Furthermore, the weak magnetic properties of certain lithium mica minerals pose challenges for conventional high-gradient magnetic separation techniques. Therefore, a new combined magnetic–flotation sorting process has been developed based on the ore characteristics. Stronger magnetic zinnwaldite is preferentially separated and enriched through high-gradient magnetic separation. Subsequent secondary grinding allows for another round of magnetic separation to obtain high-grade concentrate. Weakly magnetic lithium mica is pre-enriched by flotation, reducing throughput after impurity removal. Finally, the flotation concentrate and fine sludge are separated and enriched using superconducting technology. This process finally causes “high-gradient magnetic separation—fluorite removal flotation—lithium mica flotation—superconducting magnetic separation” of the whole particle size beneficiation. Experimental results have shown that microfine-grained lithium mica, which cannot be effectively separated by conventional magnetic separation or flotation methods, can a Li2O grade increase from 0.52% to 1.86% using superconducting magnetic separation technology. This greatly improves the ore utilization rate. Under full process experimentation, raw ore with a 0.76% Li2O grade yielded a comprehensive lithium mica concentrate with a 2.22% Li2O grade and a 77.62% recovery rate. The new process bypasses the shortcomings of conventional separation methods through the organic combination of high-gradient magnetic separation, superconducting magnetic separation, and flotation technology, achieving efficient extraction of high mud lithium mica in full grain sizes. This research provides a reference for the efficient development and utilization of complex lithium mica ores.

     

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