Flotation experiments in a Hallimond tube have been performed on calcite and apatite at pH levels and oleate concentrations judged to be interesting from the point of view of adsorption isotherms. For the calcite system, adsorption isotherms indicate precipitation of calcium oleate after monolayer formation at pH 9, 10 and 11. In the apatite system, a double layer of oleate is formed. This means that apatite, unlike calcite, is sensitive to collector reagent overdosage. With the aid of FTIR techniques it is possible to demonstrate the existence of a surface complex in the apatite system with a calcium-oleate ratio of 1:1 at monolayer coverage of the surface. In conditions corresponding to bulk precipitation of calcium oleate, this compound can be detected by FTIR analysis of unfloated material.