We have studied the structure and composition of strongly alkaline alkyl salicylate Detersol-300 and complex Kompleksal-250 additives. Potentiometric titration, chromatography, IR-spectroscopy, and X-ray diffraction were used to study the effect of the components of Detersol-300 and Komplaksal-250 on the structure of these additives. The micelles of the alkyl salicylate additives consist of spherical cores containing colloidal calcium carbonate completely coated with an adsorption shell of alkyl salicylate (sulfonate). Calcium carbonate has a vaterite structure, which does not change during synthesis of the complex salicylate/sulfonate additive Kompleksal-250.