EDTAによる塩化第二鉄液 (腐食液) の疲労測定 (第2報)

主として腐食液中の銅の分離とその定量について

抄録

The Cu²⁺ containing in the FeCl₃ solution is the worst matter to fatigue the solution and make trouble at the etching.
We determined the density of Cu²⁺ by means of the complexon titration at pH 8; as a buffer solution-1N NH₄OH:NH₄Cl, as an indicator-MX (Murexide), as a Standard solution-M/100 EDTA.
To determine only Cu²⁺ in the conjugated solution of Fe³⁺:Fe²⁺:Cu²⁺ is not easy, and we tried the following procedures to separate the Cu²⁺ from the solution.
I As seen Table 1 and 2 the results were brought out of the precipitation of Fe(OH)₃ with 1N CH₃COOH/1N CH₃COONa and titration of the separated Cu²⁺.
II Table 3 and 4 are from the results of ether-extraction of Fe³⁺ from the hydrochloric acidified sample for the determining Cu²⁺. And Fig. 1 and 2 are showing the Cu²⁺ to be absorbed at Fe(OH)₃ precipitation in I and II ways, they are according to Freundlich's formula of absorption.
III (1) Table 5, 6 and Fig. 3, 4 are showing the Cu²⁺ taken out by utlizing a strong basic ion-exchangable resin; after producing the basic complexon, it is absorbed to the resin and separated Cu²⁺ in difference of HCl acid concentration.
III (2) Table 7 and 8 are also showing the Cu²⁺ from using the resin: after producing the Fe-EDTA complexon, it is absorbed to the resin for separating Cu²⁺.
In the long run, on the numerical determination of Cu²⁺ quantity I is the most simple way among them but apt to be making error, while the others II and III are doing good measurement but a little complicated ways.