Ferrous bromide method:
In a reactor containing water, iron filings are added and bromine is added in batches with stirring. The reaction is carried out at 40 ° C to produce ferrous bromide. Then, calcium hydroxide is added to adjust the pH value, heated to boiling, and cooled and separated to remove ferrous hydroxide. The filtrate is evaporated and cooled to 30 ° C and left to stand. After decolorization, filtration, and evaporation to around 210 ° C, it is cooled to obtain calcium bromide.
