Abstract Phosphate flotation performance can be influenced by the dissolution kinetics of the minerals that compose the ore. The purpose of this work was to investigate the effect of dissolution kinetics on flotation response with oleate (collector) of calcites from different origins and genesis. The calcite samples were first purified and characterized by x-ray Fluorescence (XRF) and the Rietveld method applied to x-ray Diffractometry data (RXD). Experiments of calcite dissolution and microflotationwere performed at pH 8 and pH 10.The pH effect on the calcite dissolution and flotation indicates the possible influence of the carbonate/bicarbonate ions provided by the CO2 present in the air. In addition, the flotation response is greater as the dissolution increases, making more Ca2+ ions available to interact with collector molecules. This result corroborates the surface precipitation mechanism proposed foroleate adsorption on the calcite surface.