High purity solids are efficiently filtered, washed, agitated, reslurried and dried in a single portable device, minimizing contamination and exposure. The Nutsche filter vessel design allows withdrawal of dry filter cake using removable bottom head and filter support assembly. Drying is aided by vacuum and optional heated surfaces. Reactions and particle size homogenization are also possible. The filter-dryers are available in 5-200 liter vessel sizes and are ASME certified for full vacuum to 200 psi, -80 to 200°C. They are available in stainless steel, Hastelloy, or alternate metals, in pharmaceutical grade mechanical and electro polished finishes.