The specific results of the work investigating the effect of gas density and water temperature on bubble size were present.These were surrogate variables designed to investigate the effect of viscosity(varying water temperature) and altitude(varying gas density).The results show that there is a measurable but relatively small effect of gas density on bubble size.The D32 is revealed to increase proportionally as(ρ0/ρg)0.132.The projected impact on flotation kinetics at 4500 m versus sea level is small,of the order of 0.5% recovery loss for a bank of eight flotation cells.The effect of water temperature(4-40 °C) on bubble size is more significant than gas density.The relationship correlates with water viscosity values quite closely.A finding that D32 increases proportionally as(μ/μ20)0.776 highlights the importance of accounting for viscosity effects if,for example,large process temperature fluctuations or deviation from design/test conditions are expected. The specific results of the work investigating the effect of gas density and water temperature on bubble size were present. These were surrogate variables designed to investigate the effect of viscosity (varying water temperature) and altitude (varying gas density). The results show that there is a measurable but relatively small effect of gas density on bubble size. D32 is revealed to increase proportionally as (ρ0 / ρg) 0.132. The projected impact on flotation kinetics at 4500 m versus sea level is small, of the order of 0.5% recovery loss for a bank of eight flotation cells. The effect of water temperature (4-40 ° C) on bubble size is more significant than gas density. The relationship correlates with water viscosity values ​​quite closely. A finding that D32 increases proportionally as ( μ / μ 20) 0.776 highlights the importance of accounting for viscosity effects if, for example, large process temperature fluctuations or deviation from design / test conditions are expected.