The concentrate mass flow rate of solids of a flotation column was modeled based on geometrical principles and considering complete air recovery to the concentrate and bursting of a fraction of the bubbles that reach the top of froth. For the first consideration, the results show that concentrate mass flow rate of solids experimentally measured, is smaller than that estimated with the geometrical model. For the second consideration, bursting of a 0.45 fraction of the bubbles reaching the top of froth gave improved results (average relative error obtained under these circumstances is about 20%). (C) 2007 Elsevier Ltd. All rights reserved.