Flotation of lithium ores to obtain high-grade Li₂O concentrates. Are there any mineralogical imitations?

Abstract

The current lithium demand for batteries in general and namely for the electrical vehicle, awakened the attention for mineral processing of lithium ores. The largest lithium reserves are in brines from western South America and in pegmatites. Throughout Europe it is possible to identify several lithium deposits, namely in granitic pegmatites. An efficient mineral processing approach could be the key for an economically viable mining project. This work addresses a mineral processing study by froth flotation of samples collected in two European lithium ore pegmatites deposits -Länttä (Finland) and Gonçalo (Portugal) and aims at paying attention to some mineralogical features that can decrease the mineral processing efficiency and consequently the upgrading of the Li2O concentrates. In the case of Länttä, spodumene is the main lithium mineral and a grade of 5.20 % Li2O is the maximum obtained in the concentrates, whilst lepidolite is the lithium-bearing mineral in Gonçalo and that can be concentrated by froth flotation up to 4.50 % Li2O. Taking into consideration the Li2O content of both Lӓnttӓ spodumene and Gonçalo lepidolite, respectively 7.0 and 5.58 % Li2O, higher concentrate grades would be expected. In both studied cases, very fine quartz and albite inclusions locked in lithium silicates were identified justifying the existence of a limitation for the processing technology. The mineral processing of the two pegmatites revealed the difficulty of producing Li2O close to the stoichiometry of the spodumene and lepidolite in either of these two ores.

Quantification of lithium using handheld instruments: application of LIBS and XRF spectroscopy to assay the lithium content of mineral processing products

“…to other gangue minerals i.e., quartz, albite, and K-feldspar. [12][13][14][15][16][17][18][19] The accurate quantication of lithium is essential to evaluate the performance of lepidolite concentration, as lithium is the element that distinguishes lepidolite from gangue minerals. Traditional quantication methods, such as inductively coupled plasma optical emission spectroscopy/mass spectrometry (ICP-OES/ICP-MS) or atomic absorption spectroscopy (AAS), involve complex sample preparation and hinder inline quantication, limiting exibility in processing plants and being time-consuming.…”