The flowers of Roman chamomile (Chamaemelum nobile L. All. var. flora plena) cultivated in Iran were dried by three different drying methods of sun-drying, shade-drying and oven-drying at 40°C. The essential oils of every treatment were obtained by hydrodistillation of the flowers, and were analysed by GC and GC-MS. The oil content of the shade-dried flowers was the largest (1.9% w/w) compared to sun-drying (0.4% w/w) and oven-drying at 40°C (0.9% w/w). Drying methods had no effect on the number of chemical components of the essential oil, as 14 components were identified in the oil of every drying method. The major components were isobutyl angelate, 2-methyl butyl angelate, propyl tiglate, isoamyl angelate and 3-methylbutyl isobutyrate. However, the drying method had a significant effect on the proportion of the various components.

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This study aims to investigate the effects of operational variables on concentrate grade, recovery, separation efficiency, and kinetic parameters of the copper flotation process. For this purpose, the effects of the pulp solids content, collector and frother dosage, and preparation and concentrate collection time were studied using a Taguchi experimental design. The results of statistical analyses indicated that the concentrate collection time and pulp density were the most influential parameters on concentrate grade. Considering copper recovery, concentrate collection time, collector dosage, and pulp density were the most significant variables, in decreasing order of importance. Also, the separation efficiency was mostly influenced by the concentrate collection time. Furthermore, kinetic studies showed that the second-order rectangular distribution model perfectly matched the experimental flotation data. The highest kinetic constant of 0.0756 s −1 was obtained from the test, which was performed with 35% solids content and 40 and 20 g/t collector and frother, respectively. The highest predicted copper recovery of 99.57% was obtained from the test at 30% solids content, and the collector and frother dosages of 40 and 15 g/t, respectively.

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