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Conference publicationsAbstractsXIV conferenceThe kinetic models of dissolution of calcium carbonate in solutions of disodium salt of N,N,N',N'-ethylenediaminetetraacetic acid (complexone III)Tver State Technical University, Nab. Afanasiya Nikitina, 22, Tver, 170026, Russia, tel. +7 (4822) 449325, E-mail: sobolev@tstu.tver.ru 2 pp.The investigation of the kinetics of dissolution processes is an important problem for many areas of science and technics [1]. Earlier [2] we have proposed a new approach to the description of the kinetics of hydrolythic and oxidative dissolution of oxidic and sulphidic minerals. This approach consists in the obtaining of multifactor kinetic models of studied processes and in their subsequent physico-chemical interpretation. In this work the mentioned approach was used for the investigation of the dissolution kinetics of calcium carbonate in solutions of disodium salt of N,N,N’,N’-ethylenediaminetetraacetic acid (complexone III). The study was carried out using the rotating disc method [3]. The specific rate of CaCO3 dissolution was calculated from the amount of Ca2+ cations transferred from unit disc surface area in unit time. The contents of calcium cations in solution were measured using methods of flaming photometry and complexometric titration. The experimental technique was as described in [1,2]. The dependences of the specific rate of calcium carbonate dissolution on the concentration and the pH value of solution of complexone III as well as on temperature, disc rotation frequency, and duration of measurements were studied. The kinetic models allowing to calculate the dissolution rate of CaCO3 when these parameters change simultaneously were obtained. The conditions of kinetically and diffusion-controlled processes were detected. The details of mechanism of the studied process were revealed, and the probable thermodynamically proved schemes of interaction corresponding to the observable kinetic dependences were offered. The obtained kinetic characteristics allow to optimize the existing in heat-and-power engineering technologies of carbonate sediments removal from water-heating surfaces and to develop the new ones. |