| 摘要 |
1,252,064. Zeolitic phosphates and arsenates of iron and aluminium, and double salts thereof. TAKEDA YAKUHIN KOGYO K.K. 20 March, 1969 [20 March, 1968; 10 April, 1968; 25 July, 1968], No. 14596/69. Heading C1A. A desired metallic cation is recovered from a solution containing it by passing the solution through a zeolitic material of formula wherein M represents a univalent or half a bivalent cation and x, y and z are numbers with values 0#x#5 ; 0#y#1 ; z#9 and 0#l#1 respectively, when the cations M are substituted by the desired cation which may then be obtained by washing the exchanged zeolite material with an acid to recover the desired cations. The desired metallic cation may be Ag<SP>+</SP>, and the acid used nitric acid. The pH of the solution containing the desired metal ions may be 0À5 to 9, and the contacting with the zeolite and its subsequent washing may be effected at 50-100‹ C. The pH of the acid wash may be below 0À5. The zeolite employed may be synthesized by dissolving the sources of Al, Fe, P and/or As in water with the ranges (expressed in terms of the molar ratios of their oxides) sources of Na and/or K being dissolved therein so that (K, Na) 2 O/(Al, Fe) 2 O 3 >0À12 adjusting the pH of the resulting solution to the range in the appropriate one of the accompanying Figs. 1-4 (not shown) and heating at a temperature from 100‹ to 350‹ C. until crystals separate, usually 0À5 to a few hours, the conditions being such that solvent is not lost from the reaction system e.g. performing the reaction in a closed vessel. The crystals produced may be separated by filtration and used in the process of the invention. |
