The Crystal Forms of Alkaline Earth Metal Sulfites Produced by Heterogeneous Reaction in a Batchwise Operation

• Published in: Nippon Kagakukai shi (1972) Vol. 1979; no. 8; p. 1020
• Main Authors: MATSUNO, Takashi, KOISHI, Masumi
• Format: Journal Article
• Language: English
• Published: Tokyo Japan Science and Technology Agency 01.08.1979
• ISSN: 0369-4577
• DOI: 10.1246/nikkashi.1979.1020

The various crystalline forms of alkaline earth metal sulfites were prepared from hydroxides or carbonates of calcium, strontium or barium by heterogeneous reaction. The effect of tem-perature on the form of particles produced was remarkable. Calcium sulfite hemihydrate was obtained as a form of plates, a formless mass, spherical mass and flowery mass depending on the temperature ranging from 10 to 90° C (Fig.1 and 4). In the case of strontium sulfite, granules and a formless mass were obtained. Pillars, granules and a formless mass were obtained in the case of barium sulfite. The crystal size of calcium sulfite hemihydrate prepared from hydroxide decreased with decreasing reaction temperatures. It was revealed that a formless mass was produced when the size of a primary particle was O.4-1 μ m and a spherical mass was produced when the size was about 0.3 μ m. Formation mechanism of the spherical mass was discussed on the basis of the form of reaction products for the Ca. Cl2-Na2SO3 system, a SEM observation of the cross section of the spherical mass and their chemical composition.