iamthatiam
Rising Star
Someone I know has done many MHRB extractions and eventually developed his own using a vacuum pump and a home-made condenser. This tek is basically a regular acid-base extraction with freeze participation and evaporation, but uses vacuum to speed up the evaporation stage. It is more hassle to set up initially, but then it speeds up the purification process significantly and produces far less oxide compared to fan evaporation.
See attached PDF.
See attached PDF.