Dynamic vapor sorption measurement and identification of mineral species in industrial-scale flotation cell samples

In order to understand flotation performance in industrial-scale, it is of relevance to understand the surface properties and mineral species of materials contained in the various parts of the cell. In this work XRPD X-Ray Powder Diffraction) and DVS (Dynamic Vapor Sorption) were used to characterise the different minerals and the wettability of the sample collected at different depths in an industrial scale flotation cell. DVS is a novel technique for wettability measurement in mineral processing, of higher robustness and reproducibility compared to the Washburn technique. In the turbulent zone of the cell, the wettability properties are relatively similar, and decreases in the froth and concentrate. Differences in radial position were only found near the froth phase close to the shaft of the agitator. The main finding was that wettability information obtained by DVS could be correlated with mineral composition and particle size distribution.Funding details: VINNOVA, 2014-01943; Funding details: VINNOVA; Funding text 1: The authors wish to acknowledge Boliden Mineral and RISE for permission to publish this paper as well as VINNOVA, the Swedish Governmental Agency for Innovation Systems for financial support, grant number 2014-01943 .</p

Application of Dynamic Vapor Sorption for evaluation of hydrophobicity in industrial-scale froth flotation

The particle surface properties are essential for understanding froth flotation, particularly for the evaluation of various chemical or reagent effects.Dynamic Vapor Sorption (DVS) is used in the pharmaceutical industry for the evaluation of surface properties and has to the knowledge of the authors not been used for applications in mineral processing. This paper describes an evaluation of industrial ore samples using DVS.Four samples (feed, CuPb concentrate, Cu concentrate and Pb concentrate) from each of the Cu - Pb flotation processes in the Boliden and Garpenberg concentrators, Sweden, were analyzed by DVS in order to investigate if this technique could be used to estimate differences in their hydrophilicity. The DVS measures the water uptake as a function of the relative humidity (%RH) at constant temperature.For both series of four samples, it was found that the DVS-data are in precise agreement with the flotation theory on hydrophobicity (indicated by differences in water uptake). The feed material, without any collectors, adsorbed more water compared to the CuPb bulk concentrate, which in turn adsorbed more water than the Cu concentrate. The lead concentrate on the other hand, which had been depressed by dichromate and should be more hydrophilic, showed a higher adsorbance of water than that of the CuPb concentrate.The repeated measurements of three sub samples from one of the ore samples gave a mean value and an estimated standard deviation of 0.13 ± 0.01%. This shows that the method gives highly reproducible results and that the differences between the samples had high significance. This also shows that the DVS method can serve as a useful complement to traditionally used contact angle or capillary absorption-based measurement methods, especially when screening for new flotation reagents on industrial ore samples.Funding details: VINNOVA</p