Production of specific Mg(OH)2 granules by modifying crystallization conditions

Three methods were employed to produce specific Mg(OH)(2) (MH)granules with improved filtration efficiency, using crystallization technique. A buffer solution was utilized to improve the crystallization of MH, the spherical assembly composed of both nanosheets and hollow microspheres was obtained. A hydrothermal treatment of amorphous MH led to MH hexagonal nanoplates. In a directing growth, SO42- ions were found to strongly improve the crystallization of MH. In the current work, one-dimensional 5Mg(OH)(2)center dot MgSO4 center dot 2H(2)O whiskers and MH microspheres can be crystallized on a large scale. The filtration tests show that these specific MH granules have improved filtration properties. The current work opens up a new avenue for the production of MH granules, and the optimal filtration efficiency offers a significant control over the quality of MH-type products. (C) 2008 Elsevier B.V. All rights reserved.