| 摘要 |
A preparation method for calcium phosphate granules with low fluorine content, which includes a specialised combustion process in which the granules are heated to a high enough temperature to expand, removing the volatile fluoride compounds. The product of this invention's method has a higher content of phosphorous compared to that of the granules it was produced from. It is thoroughly mixed with conventional foods and displays good biological availability. The product is also useful as an insulator. Methods are also noticed for reduction of the fluorine content in phosphoric acid, which is used to generate the granules. The fluorine contained in phosphoric acid can be reduced by precipitation of fluoride salts from phosphoric acid already produced, in the presence of hydrochloric acid, or by decomposition of phosphoric stone with recycled phosphoric acid and hydrochloric acid, where phosphoric acid low in fluorine content is produced directly. In either of these two applications, there is use of chemically active silica. Low cost, chemically active silica can be produced from transparent crystalline silica by using the combustion method, eliminating the need for expensive diatomic silica. |
