イオン交換体による陽イオンの分離（第Ⅴ報） : アルカリ金属・アルカリ土類金属・マンガン・アルミニウムおよび鉄の分離

Cation-exchange separation of Na, K, Mg, Mn, Al and Fe was studied in this paper. Exchangers used are Amberlite IR-120, Dowex 50W-X8 and Diaion SK#1, each belonging to a strong acid resin. Eluants are prepared mixing 1mol/1 formic acid and 1mol/1 ammonium formate, thus controlling the pHof the mixture. If necessary, methanol is added in order to make separation of ions more effective. Hydrochloric acid is also uesd as an eluant for separation of alkali metals. Fe, Na and K are eluted altogether with formate buffer solution of pH=3.2, and these ions are saparated in another exchanger. Na is eluted with 0.2ⁿ-HCl first, K with 0.5ⁿ-HCl second, and Fe with formate buffer solution of pH=3.2 finally. Next to Fe group, Al is separated with pH=3.4. MN and Mg are eluted with the same buffer solution succeedingly, but these ions are rather difficult to be separated, unless a long column of exchanger is used. Ca can be separated easily from other ions with formate buffer solution above pH=4.0. Addition of methanol to an eluant changes selective coefficient of cations, which makes saparation more accurate especially in case of alkalimetals. For the separation of Fe and Al, this effect of methanol can be hardly expected. In any case, these seven cations can be separated from each other satisfactorily, using both formate buffer solution and hydrochloric acid as eluants.