Study of the Extraction Kinetics of Lithium by Leaching β-Spodumene with Hydrofluoric Acid

Abstract

Parameters affecting the kinetics of the dissolution of β-spodumene with hydrofluoric acid have been investigated. The experimental tests were carried out in a closed vessel. The influence of several parameters, such as stirring speed, temperature, and reaction time were studied in order to deduce the kinetics of the dissolution reaction. The other parameters, particle size −45 µm; HF concentration 4% v/v, and the solid-liquid ratio 0.95% w/v were kept constant. The results indicate that the stirring speed does not have an important effect on the dissolution of the mineral above 330 rpm. The extent of the leaching of β-spodumene increases with temperature and reaction time augmentations. Scanning electron microscope (SEM) analyses of some residues in which the conversion was lower than 30% indicated a selective attack on certain zones of the particle. The treatment of the experimental data was carried out using the Modelado software. The model that best represents the dissolution of the mineral is the following: ln(1 − X) = −b 1 [ln(1 + b 2 t) − b 2 t/(1 + b 2 t)]. This model is based on "nucleation and growth of nuclei" theory, and describes the style of attack physically observed by SEM on the residues.

Recovery Process of Li, Al and Si from Lepidolite by Leaching with HF

“…The extraction efficiency increases significantly when the leaching temperature is increased from 75 to 123 °C. This coincides with the results of Rosales et al (2014 and2016), who determined that the dissolution of lithium aluminosilicates (β-spodumene) with HF is strongly dependent on the temperature [17,18]. The extraction efficiency was 90% when the reaction temperature was 123 °C.…”

“…The reactions proposed for obtaining these compounds are the following [16][17][18]: The XRD patterns in Figure 1 show that the sample is mainly composed of lepidolite (ICDD 01-085-0398), with the presence of albite (ICDD 96-900-1631) and quartz (JCPDS 33-1161) as gangue.…”

“…The lepidolite dissolution with HF can be represented by the following reaction [16][17][18] In order to investigate the effect of the leaching temperature on the Li extraction, a series of leaching experiments were performed from 75 to 220 • C. Conditions of the leaching process were as follows: solid-liquid ratio, 1.82% (w/v); HF concentration, 7% (v/v); stirring speed, 330 rpm; and reaction time, 120 min. The results are presented in Figure 3 from which it can be appreciated from the error bars that the largest standard deviation in the experimental data is about ±2.5%.…”

Lithium Extraction and Hydroxysodalite Zeolite Synthesis by Hydrothermal Conversion of α-Spodumene

“…Natural α-spodumene is a lithium aluminum inosilicate mineral, which is the important mineral source for lithium extraction and generally has a high content of Li 2 O (∼5%). Since the middle of the twentieth century, α-spodumene has been processed by a traditional method which involves a high-temperature heat treatment (∼1100 °C) to transform the inert α-spodumene into active β-spodumene, followed by sulfuric acid curing at around 250 °C and water leaching. − Although some direct leaching processes have been reported, − heat treatment is still a necessary step. The phase transformation of α-spodumene involves high energy consumption.…”

Lithium extraction from Zimbabwean petalite using ammonium bifluoride

“…Die proses is energie-intensief en gevolglik duur. (Guo et al, 2019, Hui et al, 2019, Rosales et al, 2013, Rosales et al, 2016 (Garrett, 2004, Hien-Dinh et al, 2015, Kondás et al, 2006, Guo et al, 2019, Sitando and Crouse, 2012, Wietelmann and Bauer, 2003. HF is egter 'n gevaarlike suur om mee te werk, genereer toksiese verbindings, en prosesontwikkeling verg spesialiskennis (Andreev et al 2007a, Rosales et al, 2013.…”