| 摘要 |
Barium hydroxide is prepared by contacting an aqueous solution of a barium compound other than barium sulphide either with a strongly acidic cation exchange resin in the sodium or potassium form, the isolated resin being at least partly regenerated with sodium or potassium hydroxide, e.g. 3-8N, to yield simultaneously barium hydroxide solution, or with a strongly basic anion exchange resin in the hydroxyl form, the barium hydroxide solution being the effluent. A concentrated solution of barium chloride, nitrate or acetate at up to 100 DEG c. may be passed through a bed of the cation exchange resin in the sodium form, and the resin, after water washing, regenerated by passing excess 4N NaOH in the reverse direction. Barium hydroxide octahydrate crystallizes from the concentrated and cooled regeneration effluent and is washed with cold water. The mother liquor, after addition of sodium hydroxide, is recycled. Alternatively, barium chloride, nitrate or acetate solution at ambient temperature may be passed through a bed of the anion exchange resin in the hydroxyl form, when barium hydroxide octahydrate crystallizes from the effluent from the resin. Sodium or potassium chloride, nitrate or acetate may be recovered from the effluent from the cation exchange resin. |
