Bromine Production

Seawater, lakes and wells brine as well as potassium manufacture liquor (with Bromine concentration up to 4-5 kg/m³) serve as main bromine sources. Bromine is isolated by passing Cl₂ through with following sublimation by water vapour if Bromine concentration exceeds 1 kg/m³ or by air, if less, in packed columns made of ceramics, glass or titanium. Solutions with alkali reaction are previously acidified, usually by H₂SO₄ until pH 2.5-3.0. The heated reaction solution is supplied to the top of the column, water vapour - through the bottom and Cl₂ somewhat higher. Vapour, which comes out of the column, is condensed. Then Bromine is separated from water and refined from Cl₂ and organic contamination.

If Bromine less than 1 kg/m³ it is separated or by air. Solution previously treated by Cl₂ is supplied to the top of the column and air - to the bottom. Bromine is captured by FeBr₂ from the bromine-air mixture. FeBr₃, the reaction product is reduced by iron turnings until FeBr₂. In another method SO₂ is added to the bromine-air mixture. In the presence of water HBr and H₂SO₄ appear. Bromine is isolated by Cl₂. For Bromine absorption NaOH or Na₂CO₃ (3Na₂CO₃ + 3Br₂ = 5NaBr + NaBrO₃ + 3CO₂) are used. Bromine is isolated by H₂SO₄. Residual Bromine is treated by Na₂S₂O₃.