mft stands for “material for treatment”, non-mft satnds for “material not for treatment”. These are the two categories by which products are classified in the APOS system model. As the name implies, a “material for treatment” requires to be treated in a treatment activity in the linking of the APOS system model, while this is not the case for non-mft classified products. For example the mft "municipal solid waste" calls "treatment of municipal solid waste, incineration" and other treatment activities through the "market for municipal solid waste".)
Read more about the APOS system model and its linking rules here.