| 摘要 |
1,137,074. Purification of phosphoric acid. DOW CHEMICAL CO. 17 May, 1966 [21 May, 1965], No. 21795/66. Heading C1A. Aqueous phosphoric acid solution is treated for the removal of calcium therefrom by extracting the solution with an organic solvent not soluble in water to more than 10 wt. per cent of the mixture, and treating the thus-obtained organic solution of phosphoric acid with a cation-exchange resin which is a sulphonated copolymer of styrene and divinylbenzene, e.g. " Dowex 50 " (Registered Trade Mark). Aqueous phosphoric acid or sodium phosphate are then recovered by washing the organic solution with water or sodium hydroxide solution respectively. The organic solvent may be a trialkyl phosphate, an aliphatic alcohol, cyclohexanol, methylcyclohexanol, methylcyclohexanone, an ester, an ether or an amide, and may optionally be admixed with a diluent such as toluene, " Varsol " (Registered Trade Mark), benzene, decane, xylene, or kerosene. The process is especially suitable for the treatment of phosphoric acid obtained by treating phosphate rock or ore with a mineral acid such as HCI, H 2 SO 4 or HNO 3 . |
