Reverse Flotation Separation of Fluorite from Calcite: A Novel Reagent Scheme

Jianjun Wang,Zhiyong Gao,Zihan Zhou,Wei Sun,Yuesheng Gao,Yuehua Hu

doi:10.3390/min8080313

Jianjun Wang, Zhiyong Gao + Show 4 more

Open Access

https://doi.org/10.3390/min8080313

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Abstract

Fluorite (CaF2), as an important strategic mineral source, is usually separated from calcite by the common froth flotation method, but this separation is still not selective enough. The development of a selective collector and/or depressant is the key to achieving high selective separation. 1-Hydroxyethylidene-1,1-diphosphonic acid (HEDP or H4L) is widely used as an environmentally friendly water treatment reagent due to its low cost and excellent anti-scaling performance in an aqueous solution. In this study, a novel reagent scheme was developed using HEDP as a fluorite depressant and sodium oleate (NaOL) as a calcite collector for the first time. When 3 × 10−5 mol/L of HEDP and 6 × 10−5 mol/L of NaOL were used at pH 6, the optimal selective separation for single minerals and mixed binary minerals was obtained. Zeta potential measurements indicated that HEDP possessed a stronger adsorption on fluorite than calcite, while NaOL did the opposite. This novel reagent scheme is of low cost, uses a small dosage, and is friendly to the environment, which makes it a promising reagent scheme for fluorite flotation in industrial application.

Highlights

Fluorite (CaF2 ) is the most important mineral source that produces fluorine-based chemicals and materials in a wide range of engineering and technological applications [1,2]
The selective flotation separation remains a challenge since both minerals have similar active Ca2+ ions on their commonly exposed cleavage surfaces, leading to similar and strong flotation behavior when using conventional fatty acid collectors such as sodium oleate (NaOL) [5,6,7,8,9]
The X-ray powder diffraction spectra showed that the purity of both fluorite and calcite was above 98%

Summary

Introduction

Fluorite (CaF2 ) is the most important mineral source that produces fluorine-based chemicals and materials in a wide range of engineering and technological applications [1,2]. Fluorite is associated with calcite (CaCO3 ) and separated from calcite through the most common method of froth flotation [3,4]. In order to separate fluorite from calcite effectively, extensive documents have concentrated on screening depressants for calcite, such as acidized sodium silicate (SS) [10,11], valonea extract [12], quebracho [13], and tannin and starch [14]. Low-cost SS, in particular, is a widely-used depressant in industry for calcite in fluorite flotation. The main disadvantages include complicated flotation flowsheets and high operation costs for depressing calcite in practice [15]

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