| 摘要 |
PURPOSE:To develop phosphoric acid removing capacity equal to that of a crystallized material based on magnesia clinker being a matrix material, by using a material prepared by fixedly depositing magnesium oxide and calcium salt to the surface of a granular solid substance having absolute specific gravity of a specific value or less and insoluble in water. CONSTITUTION:A granular solid substance having absolute specific gravity of 3.5 or less and insoluble in water, for example, silica sand, silica stone or zeolite is immersed in a slurry containing 10-30% of magnesium oxide while the impregnated solid substance is baked at 1,000-2,000 deg.C to fixedly deposit magnesium oxide to the surface thereof. In the next step, the baked substance is immersed in a solution containing a proper amount of calcium chloride and calcium hydroxide and the impregnated substance is heated and dried at 120-200 deg.C for about 2hr to further fixedly deposit the calcium salts.
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