| 摘要 |
<p>The present invention relates to acicular gypsum crystals, so-called fibrous gypsum, the crystals containing two waters of crystallization. The invention also relates to a method for the manufacture of such crystals, in which gypsum is dissolved to saturation in a sulphuric-acid solution containing 5-15% H2SO4 at a temperature of 70-100 DEG C, whereafter the saturated solution is permitted to cool, thereby to crystallize out acicular gypsum crystals of dihydrate form. The resultant crystals, fibrous gypsum, can be used, inter alia, in the manufacture of lightweight gypsum products, such as fire-resistant insulating material.</p> |
