| 摘要 |
PURPOSE:To collect an active ingredient in naturally occurring salt as a composition according to uses by forming precipitates from an aqueous solution containing the naturally occurring salt dissolved therein with a strong alkaline agent according a specific method, separating the precipitates, concentrating the resultant residual aqueous solution, then cooling the concentrate and separating the formed precipitates and the aqueous solution. CONSTITUTION:A strong acid containing sulfate ions is added to regulate an aqueous solution containing naturally occurring salt dissolved therein to a low pH. A strong alkaline agent is then added to provide a high pH. Precipitates produced at that time and the residual aqueous solution are separated. The remaining aqueous solution produced in the aforementioned step is further concentrated and then cooled to separate the produced precipitates and aqueous solution. A dilute sulfuric acid of several % concentration can be used as the strong acid containing the sulfate ions; however, an aqueous solution prepared by adding 3-5% concentrated sulfuric acid to an aqueous solution containing activated calcium phosphate dissolved therein and removing the precipitates can also be used. |
