| abstract |
The present invention discloses a cycled preparation method that uses sodium fluoborate as intermediate raw material and produces boron element and simultaneously sodium cryolite, comprising the following steps: A) adding hydrofluoric acid to boric acid or boron anhydride to react and produce fluoroboric acid; B) adding sodium carbonate solution to the fluoroboric acid, concentrating crystal to obtain sodium fluoborate; C) placing the sodium fluoborate in a reactor, and adding aluminum to react and produce boron element and sodium cryolite; or placing aluminum in a reactor, and adding the sodium fluoborate to react and produce boron element and sodium cryolite; D) extracting the sodium cryolite, placing into a rotary reactor with concentrated sulfuric acid to react and produce hydrogen fluoride gas and sodium aluminum sulfate, and collecting the hydrogen fluoride gas and dissolving the gas into water to obtain hydrofluoric acid; E) the obtained hydrofluoric acid is cycled to step A to perform leaching on boric acid or boron anhydride. The present invention recycles the byproduct, sodium cryolite, shortens the preparation process of boron element, lowers the comprehensive production cost, enhances the production efficiency, and reduces environmental pollution. |