Particle containing alkali

摘要

[1] Alkali-containing particles which comprise particles (a) containing an alkali and having an average particle diameter of 150-1,000 µm and, formed on the surface thereof, a layer of clay mineral particles (b) which have a water-holding ability as calculated by the following method of 200 mass% or higher and have an average particle diameter of 1-200 µm. The alkali-containing particles have excellent unsusceptibility to caking while retaining intact solubility in water. Also provided is [2] a method of preventing alkali-containing particles from caking which comprises forming a layer of the clay mineral particles (b) on the surface of the particles (a). (Calculation of water-holding ability: the dispersion resulting from a swelling power examination of clay mineral particles (b) which has been made in accordance with JBAS-104-77 is filtered with suction to determine the mass (A) of the clay mineral particles (b) remaining on the filter paper, and the water-holding ability is calculated from the mass (A) and from the mass (B) of the clay mineral particles (b) dried by JIS K0068 'loss-on-drying method', using the equation: water-holding ability (%) = [(A-B)/B]×100.)