a person of skill in the art for example for a 6 liter froth flotation column the flow rate of the nonreactive gas will preferably range from about 10 to about 45 standard liters per minute slpm porous materials such as screens nozzles filters and like devices with different pore sizes may also be employed to produce bubbles at the lower portion of the froth flotation device while an exemplary batch type froth flotation deinking cell 10 has been illustrated it should be appreciated that any froth flotation device such as a batch or continuous type column cell or a rotating deinking cell or dissolved gas flotation deinking cell can be used in accordance with the principles of the present invention the present invention recognizes lemlich 39 s expression of a relationship between liquid volumetric fraction in a froth and the conductivity of the froth relative to the suspension conductivity as set forth below in equation 1 leimlich r a theory for the limiting conductivity of polyhedral foam at low density j colloid interface sci 64 107 1978 where u03c3 froth is the conductivity of the froth relative to the liquid conductivity and u03c6 1 is the liquid volumetric fraction in the froth equation 1 however has only been applied to.