Kinetics of Dissolution of Elemental Sulfur in Alkali to Obtain a Sulfidizing Reagent
Year: 2026
Type: article
Abstract: Of practical interest for the purification of wastewater and basement waters from zinc and copper is the use of a sulfidizing reagent obtained by the interaction of elemental sulfur and caustic soda in a mass ratio of one to one. The purpose of the work was to determine the kinetic characteristics of the sulfidizer reagent formation process, necessary for the calculation and selection of technological equipment, its operating mode during the development of technological regulations for wastewater treatment. The rotating disk method was used to study the process of dissolution of elemental sulfur. It was found that the specific rate of sulfur dissolution and the rate constant of dissolution do not depend on the size of the area of the discs used (1.13‒7.54 cm2). At the same time they increase with an increase in the concentration of caustic soda from 1 to 5 mol/ dm3, the intensity of rotation of the disc from 15 to 35 rad/s and the temperature of an aqueous alkali solution with 313 to 363 K. In the studied intervals, a directly proportional relationship was revealed between the following indicators of the dissolution process of elemental sulfur: the specific dissolution rate on the intensity of disk rotation to the degree of 0.5; the amount of dissolved sulfur from the disk area. All other conditions being the same; the logarithm of the specific sulfur dissolution rate from the logarithm of the initial concentration of caustic soda; the logarithm of the rate constant of dissolution from the reverse temperature of the aqueous solution of caustic soda. The apparent order of the reaction in terms of alkali concentration, numerically equal to the ratio of the increment of the logarithm of the specific rate of dissolution of sulfur to the increment of the logarithm of the initial concentration of caustic soda, is rounded 1.5. The value of the activation energy at a disk rotation intensity of at least 25 rad/s is characterized by a high value of 130 kJ/mol, which, combined with the effect of the mixing intensity of the solution on the rate of interaction of elemental sulfur with caustic soda, indicates that the process proceeds in a mixed diffusion-kinetic regime. For citation: Verkhodanov R.I., Timofeev K.L., Maltsev G.I., Yakornov S.A. Kinetics of dissolution of elemental sulfur in alkali to obtain a sulfidizing reagent. ChemChemTech [Izv. Vyssh. Uchebn. Zaved. Khim. Khim. Tekhnol.]. 2026. V. 69. N 10. P. 27-36. DOI: 10.6060/ivkkt.20266910.7148.
Language: English
Subfield: Metals and Alloys
Field: Materials Science
Domain: Physical Sciences
Open Access status: diamond
OpenAlex ID: W7204929451