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This paper aims at contributing to the possibility of electrically separating K-feldspar/Na-feldspar and quartz/feldspar, investigating the behaviour of mixtures composed of K-feldspar, Na-feldspar and quartz concentrates. The findings highlight the importance of preheating the material and of interparticle contact. Tests conducted on binary mixtures of K-feldspar/Na-feldspar, K-feldspar/quartz and Na-feldspar/quartz showed that it is possible to achieve satisfactory results in the separation of these species, by triboelectrical charging of the material, preheated to temperatures above 100 °C, using a free fall chamber. Tests carried out on ternary mixtures have demonstrated that additional pretreatment with HF solutions improves the results

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An investigation was conducted into the Tertiary ignimbrite formations in the Romana area in NW Sardinia. Scanning electron microscopy–energy‐dispersive spectrometry indicated the presence of clinoptilolite and subordinate smectite, quartz, mordenite and calcite. Laboratory analyses of representative samples collected from the deposit indicated a cation exchange capacity ranging from 85 to 135 mEq per 100 g. Ion exchange experiments conducted in flasks containing different initial cation concentrations and in columns supplied with solution having constant cation concentration, showed different selectivity towards the cations examined, in the order: NH4+> Pb2+> Cd2+> Cu2+> Zn2+> Mn2+> Ni2+. Compared to the untreated material, under the experimental conditions used and considering the eluate, and the Italian regulatory limits for discharge into surface waters, the zeolite treated with a 1‐N NaCl solution yielded a 1.3–5‐fold increase in the volume of treated water, depending on the cation examined. The experimental results obtained show that the cationic exchange properties of the zeolite rock from the Romana deposit are comparable with the average quality of zeolites currently imported into Italy from non‐European countries.