Flotation Separation of Chalcopyrite and Talc Using Calcium Ions and Calcium Lignosulfonate as a Combined Depressant

Qiongyin Mai,Leming Ou,Hanyu Zhou

doi:10.3390/met11040651

Abstract

As a major gangue mineral in sulfide ores, talc is difficult to separate from chalcopyrite in the flotation process due to its natural floatability, which affects the subsequent smelting process. In this study, the effects of calcium ions and calcium lignosulfonate (CLS) as a combination depressant for talc were systematically investigated along with the fundamental mechanisms. The results of our flotation tests showed the talc floating can be effectively depressed via the combination depressant effect of calcium ions and CLS over the pH range of 6–12. Measurements of the adsorption capacity, zeta potential, and Fourier transform infrared (FTIR) showed an enhancement of the adsorption capacity and adsorption strength of CLS on the talc surface after calcium ions were added. This result indicates that calcium ions adsorbed onto the talc, neutralized the negative charge on the surface of talc, generated the binding site with CLS, and formed the [talc-Ca2+/Ca(OH)+-CLS] system by strong adsorption. Further, the coverage rate of CLS on talc was significantly improved after the addition of calcium ions, as shown in the AFM imaging.

Highlights

The use of copper, a key metal in the green energy transition, is expected to rise as long as the demand for electric cars, solar, and wind power continues to rise [1]
The results showed that the flotation separation of chalcopyrite and talc could not be achieved without the use of depressants
AFM Imaging Results In order to study the effect of calcium ions on the adsorption behavior of calcium lignosulfonate (CLS) on the talc surface, the morphology of the CLS (200 mg/L, pH = 8) adsorption layer was studied by an AFM imaging method

Summary

Introduction

The use of copper, a key metal in the green energy transition, is expected to rise as long as the demand for electric cars, solar, and wind power continues to rise [1]. The study of an efficient talc depressant is the key to realize the flotation separation of copper sulfide minerals and talc. The adsorption of xanthan gum on the talc surface is achieved through physical action, with hydrophobic interactions acting as a main driving force [19]. Parolis et al studied the effect of divalent cations Ca2+ and Mg2+ and monovalent K+ ions on the behavior of CMC adsorption They found that Ca2+ and Mg2+ were far more efficient in promoting the adsorption of CMC onto talc surfaces than K+ ions [16]. Note that CMC is an effective talc depressant in copper sulfide flotation. It is of great significance to find a reagent with high selectivity for talc depression in copper sulfide flotation

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Conclusion