Croatica Chemica Acta, Vol. 30 No. 4, 1958.
Original scientific paper
The Separation of the Bivalent from the Trivalent Kations in the Presence of Phosphate by a Modified Ammonia Method, and Comparison of Results thus Obtained with Results of Separation by the Urea Method
F. Krleža
; Laboratory of Analytical Chemistry, PhilosophicaL Faculty, University, Sarajevo, Bosnia and Herzegovina, Yugoslavia
Abstract
The separation of Mg, Ca, Sr and Ba from Al and Cr in the presence of phosphate has been accomplished by adding dropwise the system in which the cations have to be separated to a solution of ammonium nitrate containing the quantity of freshly distilled ammonia necessary to give a p H-value of 6.9 to 7 in the solution after precipitation. The upper limits of phosphate content at which the separation is still feasible have been determined both for the above separations and for the separation of the bivalent ions from Fe in the presence of phosphate. The comparison of the results thus obtained with the results of separations of the same cations by the urea method shows that the upper limit of phosphate content at which the separation succeeds is higher for the urea method than for the ammonia method. In both methods this limit - for a given trivalent ion and a changing bivalent ion - changes in proportion to the solubility product of the secondary phosphate of the bivalent metal, and - for a given bivalent ion and a changing trivalent ion - in inverse proportion to the solubility product of the phosphate of the trivalent metal.
Keywords
Hrčak ID:
245378
URI
Publication date:
8.5.1959.
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