The invention relates to the technical field of
sodium borohydride preparation, in particular to a
sodium borohydride preparation method based on concentration and
crystallization treatment. Comprising the following steps: adding crude
sodium borohydride and deionized water into a high-pressure kettle according to a
mass ratio, stirring, and filtering to obtain extract liquor; pumping the extract liquor into a
reverse osmosis system, and carrying out membrane concentration; the concentrated solution is transferred to a
crystallization kettle,
polyethylene glycol-4000 is added, gradient cooling is executed for
crystallization, and in the second stage of gradient cooling,
sodium borohydride seed crystals are added, and meanwhile ultrasonic
waves are applied for auxiliary crystallization; pumping the crystallized
slurry into a horizontal centrifugal
machine, separating crystals, putting the obtained crystals into a double-cone rotary
drying machine, and
drying to obtain concentrated
sodium borohydride crystals; a traditional
evaporation process is replaced by
reverse osmosis membrane low-temperature concentration, by-product
sodium metaborate impurity pollution is eradicated, the source of the phenomenon that
metal ions induce dendritic
crystal growth is eliminated, high-purity
sodium borohydride crystals can be obtained through single crystallization, and the product yield is increased.