Abstract The niobium mineral deposits in Brazil account for more than 70% of the world's known reserves. Currently flotation of pyrochlore is carried out in the Araxa plant using amines as collector at low pH, in the presence of NaF as an activator and with the addition of a modifier. In the present work bench scale flotation kinetic testwork was conducted, aimed at a better understanding of some aspects of the process used. A rate model based on equations for fast floating and slow floating particles was used for describing the cumulative recovery versus time. The results showed that the control of collector (amine acetate) at a minimum level was essential for effective action of the activator and modifiers studied. In the rougher stage, best results were obtained with the collector at 100g/t. The use of NaF at a dosage higher than 1000g/t significantly affected the cleaner concentrate grade.