| 摘要 |
<p>PROBLEM TO BE SOLVED: To obtain an agent for removing phosphates with a higher adsorption coefficient by kneading calcium carbonate, a magnesium-containing mineral immersed in a diluted sulfuric acid, a porous material for increasing the specific surface area, and a binder and forming the resultant mixture into granular bodies. SOLUTION: Calcium carbonate, a magnesium-containing mineral, a porous material for increasing the specific surface area, and a binder, which are respectively formed into powder granules are prepared and at first the powder granules of the magnesium- containing mineral are immersed in a diluted sulfuric acid to give a slurry and the other components are added to the resultant slurry and kneaded for a proper time, and then the resultant mixture is granulated into a proper size, for example about 2-3cm, using a granulating apparatus. Consequently, calcium derived from calcium carbonate is gradually dissolved as calcium sulfate due to the diluted sulfuric acid used for the treatment of the magnesiumcontaining mineral and also magnesium derived from the magnesium-containing mineral is gradually dissolved as magnesium sulfate and the calcium and the magnesium are reacted with pyrophosphoric acid and metaphosphoric acid, so that phosphates in water are made insoluble and phosphates are removed and consequently high efficiency of the removal of the phosphates can be achieved.</p> |
