The Mixer is set to produce a product "ciment1" and for that it requires ingredients.The DePortioner provides the material "clinker", which is not part of the ingredients. Therefore it will not be used and your model blocks.
Your Mixer asks for the ingredients belonging to ciment1: ciment and retour_séperateur. Only one of these is available (retour_séperateur). The DePortioner provides the material clinker at the time of blocking. Since this material is not used by the current recipe of your Mixer, there will be no more material flow.
The DePortioner only produces one material at once, it does not mix materials like a Mixer does.