Efficient Extraction of Lithium and Rubidium from Polylithionite via Alkaline Leaching Combined with Solvent Extraction and Precipitation

Abstract

Lithium and rubidium, as important alkali metals, have a wide range of applications in many fields because of their unique physical and chemical properties. This paper proposes a novel method for the extraction of lithium and rubidium from polylithionite. The process primarily involves alkaline leaching, solvent extraction of rubidium, lithium phosphate precipitation, and zeolite synthesis. Results of alkaline leaching experiments show that the leaching rates of lithium and rubidium are 96.43 and 97.50%, respectively, under a leaching temperature of 250 °C, an NaOH concentration of 600 g/L, a leaching duration of 3 h, and a liquid−solid ratio of 7:1 mL/g. Through solvent extraction, the extraction rate of rubidium can reach 99.5%. More than 93.96% of lithium can be recycled by adding phosphoric acid to prepare lithium phosphate. The obtained basic leaching residue is pretreated to synthesize zeolite, achieving reasonable utilization of the waste residue. The rational use of waste residue has added value to the process and promoted the sustainable use of resources.

Novel Technology for Synergistic Extraction of Li and Rb from a Complex Lithium Concentrate

“…The comparison of different alkali processes is shown in Table . The previous research processes ,,, all used hydrothermal alkali leaching to extract Li or Rb from α-spodumene or polylithionite ore. In addition, Song et al promoted the decomposition of the mineral phase of α-spodumene by adding CaO.…”

Mechanochemical Lithium Extraction and Zeolite Synthesis from End-of-Life Glass–Ceramics

“…According to the literature, H 3 PO 4 was added to the leaching liquid at a temperature of 90 °C and at P:Li ratios ranging between 1.2:3.0 and 1.8:3.0. 34,44 The reaction that takes place during precipitation is shown in eq 4.…”

“…27−32 Recently, a combined process for hydrothermal lithium extraction and hydrosodalite synthesis was published for the minerals α-spodumene LiAl[Si 2 O 6 ] with space group C2/c 33 and polylithionite, a member of the mica group KLi 2 Al[Si 4 O 10 (F,OH) 2 ], also of monoclinic C2/c structure. 34 However, there is no report on a mechanochemical conversion from glass−ceramics to zeolites with simultaneous lithium extraction.…”

“…Zeolites are a group of crystalline microporous aluminosilicates, which are characterized by their three-dimensional framework structure, large surface area, uniform pore size distribution, and high thermal and chemical stability. − Hydrosodalites are special zeolites with the general formula Na 6+ x [Al 6 Si 6 O 24 ]­(OH) x · n H 2 O and the two endmembers (i) basic hydrosodalite (or hydroxysodalite hydrate) with a chemical formula Na 8 [Al 6 Si 6 O 24 ]­(OH) 2 ·2H 2 O (for x = 2, n = 2) and (ii) nonbasic hydrosodalite with its corresponding formula Na 6 [Al 6 Si 6 O 24 ]·8H 2 O (for x = 0, n = 8) . Taking advantage of the special properties of hydrosodalites in molecular sieving and selective adsorption, previous researchers have investigated applications such as the removal of hazardous heavy metal ions in aqueous media or membrane materials. , As a result of their versatile application possibilities, numerous efforts were made to produce hydrosodalites and related zeolites from low cost precursors like basalt powder, kaolin, , or fly ash. ,− The most common method for zeolite synthesis is hydrothermal alkaline activation of aluminosilicate materials, but mechanochemistry was developed as a new trend for solvent-free synthesis and modification of zeolite materials. − Recently, a combined process for hydrothermal lithium extraction and hydrosodalite synthesis was published for the minerals α-spodumene LiAl­[Si 2 O 6 ] with space group C 2/ c and polylithionite, a member of the mica group KLi 2 Al[Si 4 O 10 (F,OH) 2 ], also of monoclinic C 2/ c structure . However, there is no report on a mechanochemical conversion from glass–ceramics to zeolites with simultaneous lithium extraction.…”

Lithium Harvesting from the Most Abundant Primary and Secondary Sources: A Comparative Study on Conventional and Membrane Technologies

“…Among these resources, lithium recovery from lithium-bearing minerals and clays (spodumene, lepidolite, zinnwalidite, ambloygonite and petalite) has been well studied. Some commonly used methods developed to date include chemical leaching [26], bioleaching [27], and pressure leaching [28]. Whilst harvesting a high purity Li 2 CO 3 at 99%, these conventional processes are generally energy-intensive and cause environmental concerns [29,30].…”