製塩副産石膏に関する研究 (第1報)

苦汁の塩化石灰処理による石膏の製造について

抄録

We investigated the conditions under which granular, dense and colorless crystal of gypsum. could be obtained without adding extraneous anions nor using recrystallization method of hemihydrate in the treatment of bittern with calcium chloride.
The results are summarized as follows : Granular and colorless gypsum can easily be produced by controlling the following physical, chemical conditions, irrespective of concentration of the raw materials :
1) Pouring simultaneouly both reaction solutions into the reaction vessel in order to reduce [Ca″] × [SO₄″] ion product and reaction velocity.
2) Maintaining the reaction temperature as high as possible, but in the range of CaSO₄·2H₂O formation.
3) Maintaining suspension density of crystals as dense as possible, to delay crystal growth.
4) Using faint colored or debromided bittern, the latter having been previously treated with chlorine.