Recovery of lithium from kaolin mining waste material

Iqbal, Zubera (2015). Recovery of lithium from kaolin mining waste material. University of Birmingham. Ph.D.

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Abstract

Lithium is considered a borderline strategically important metal for the UK due to the limited availability of primary deposits, of sufficient grade, for economic processing (Naden, 2012). The rising demand, of approximately 10% yearly, has promulgated investigations for the development of secondary sources of lithium in order to secure long term reserves for the UK and Europe (Jaskula, 2015).
The British Geological Survey (1987) estimated that the St Austell granite contained up to 3.3 million tonnes of recoverable lithium. Imerys Ltd also identified lithium-bearing mineral in their kaolin waste material in Beauvoir, containing up to 0.89 wt.% Li2O. The lithium-bearing minerals identified were; lepidolite (K(Li,Al)3(Si,Al)4O10(F,OH)2) and zinnwaldite (KLiFeAl(AlSi3)O10(F,OH)2), which can contain between 3.0 to 7.7 wt.% Li2O and 2.0 to 5.0 wt.% Li2O, respectively (Garrett, 2004).
Lithium flotation concentrates containing up to 5.0 wt.% Li2O were optimised for the Beauvoir waste material with up to 80% lithium recoveries, whereas a lower flotation grade of 0.5 wt.% Li2O was found for the St Austell material. The St Austell waste materials did not prove viable to process via conventional flotation routes hence a novel process route for the bio-recovery of lithium from lithium rich micas was developed. Extraction of lithium by bioleaching has demonstrated the ability of fungi, of Aspergillus niger group, to leach lithium from the lepidolite in significant quantity, achieving 125mg/L of lithium in solution after twelve weeks of bio-leaching, at a recovery of 45%. Following this research, Imerys are applying to build a pilot plant, securing funding through the Innovative UK grant.

Type of Work:

Thesis (Doctorates > Ph.D.)

Award Type:

Doctorates > Ph.D.

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