A mixer for ceramic feedstock pellets with a tank, a mixing shaft, and a heat exchanger including a cooler for the cooling of the content of this tank is provided. A controller controls the heat exchanger which includes a heater arranged to heat the content of this tank to a temperature comprised between a lower temperature (TINF) and a higher temperature (TSUP) stored in a memory for a specific mixture, and the heater exchanges energy with a heat exchange and mixing temperature maintenance circuit, external to this tank, and wherein the thermal inertia of this circuit is higher than that of this fully loaded tank. The invention also concerns a method for mixing raw material for powder metallurgy, implementing a specific injection molding composition and a specific binder.