This article presents the results of a study on the influence of technological parameters on the physicochemical properties of the EDTA-4Na - FeCl3 - H2O system within a wide range of selected technological parameters. Specifically, the effect of the concentration of FeCl3 solutions and their ratio relative to EDTA-4Na was investigated. It was found that with an increase in the EDTA-4Na ratio, the system's pH increases from 1.271 - 1.608 to 2.938 - 4.117 and 6.426 - 7.795. Furthermore, with an increase in FeCl3 concentration at a constant ratio, a slight decrease in pH is observed up to 30%, followed by a sharp increase at 40%. Further increase in FeCl3 concentration leads to a slight decrease. This pattern is consistent across all ratios. The pH difference of the system when using 30% and 10% FeCl3 solutions is 0.216, 2.89, and 1.327 at ratios of 50, 100, and 150%, respectively.
Matsalayeva et al. (2026) studied this question.