Froth-Flotation Separation as an Alternative for the Treatment of Soil Enriched with Fluorine Derived from Mica

Abstract

Fluorine (F) enrichment originating from natural sources is difficult to remove using chemical washing methods due to the large chemical-resistant residual fraction. This study evaluates the feasibility of using a froth-flotation separation method to remediate soil with a high F concentration caused by mica weathering, and it investigates the optimal conditions for this process, including pH of the slurry, collector dosage, and sample mechanical preparation strategy. The established optimum conditions are pH 3.5, 300 mg/kg collector dosage (tallow amine acetate), which can effectively separate quartz and mica, and a sieving-and-milling strategy that involves discarding particles of size < 0.05 mm, milling those in the range of 0.5–2.0 mm (until < approx. 0.3 mm), and mixing particles with sizes in the range of 0.05–0.5 mm. The target contamination level of 400 mg/kg for the test soil was not met after the first flotation separation process. However, after milling the residue of the first process and subjecting it to a second flotation separation process, the required contamination level was achieved. Consequently, the proposed froth-flotation separation process can be used as a successful alternative technique to remediate F-enriched soils from natural origin that have highly chemical-resistant forms.

Flotation separation influenced by the rheological properties of diaspore-pyrite mixed pulp

“…The methods used for desulfurization of high-sulfur bauxite were wet desulfurization, calcination desulfurization, flotation desulfurization, microbial desulfurization and so on (Wu et al, 2020;Zhao et al, 2021) , and flotation has been widely applied because of its low cost and simple operation. Flotation is a method to separate target minerals from gangue minerals by different effects of minerals on liquid and gas in pulp according to the differences in physical and chemical properties of mineral particles (Cho et al, 2022;Jin et al, 2023;Sajjad and Otsuki, 2022;Saneie et al, 2022), which is one of the most effective mineral processing methods for separating and enriching target minerals (Cook and Gibson 2023;Shao et al, 2023;Xiao et al, 2022), especially for high-sulfur bauxite (Cheng et al, 2023). The main sulfide mineral in bauxite is pyrite with strong hydrophobicity, for which the most effective separation method is reverse flotation.…”