沈降性炭酸カルシウム結晶の生長過程について : 沈降性炭酸カルシウムに関する研究 (続報)

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In the preceding report the author have mentioned the relations among the various kinds of precipitated CaCO3 crystals, namely globular, rhombic, flowery and needle shaped forms, which were obtained by adding (NH4)2CO3 solution to the solution of CaCl2.The present paper concerns with another method of preparing CaCO3 and with the conditions of the appearence of globular and other unstable form as well as the process of the growth of above crystals.X-ray diffraction method and microscopic observation were jointly used for the identification of the polytypism.The results are summarized as follows:1) It was observed that the flowery and needle shaped type grew from the globular type μ-CaCO3 as shown by the photographic records.2) The necessary condition for the appearnace of unstable types seems to be the existence of the momentary local supersaturation of Ca2+ and CO32-.3) The appearance of aragonite type crystals was disturbed by the addition of the salts which increase the solubility of CaCO3.
社団法人日本セラミックス協会の論文
1958-08-01