Claims
- 1. A process for preparing dicalcium phosphate dihydrate having improved monofluorophosphate compatibility which consists essentially of the steps of:
- (a) reacting a slaked lime slurry with phosphoric acid to form a monocalcium phosphate solution;
- (b) further reacting said monocalcium phosphate solution with additional slaked lime slurry to form a dicalcium phosphate dihydrate slurry having a final pH ranging from above about 2.2 to below about 5.5;
- (c) separating the dicalcium phosphate dihydrate from said slurry.
- 2. The process of claim 1 wherein an acid other than pyrophosphoric acid is added during or after step (b).
- 3. The process of claim 2 wherein said acid is an acid selected from the group consisting of orthophosphoric acid, polymeta phosphoric acid, tri and tetrameta phosphoric acids, sulfuric acid, triphosphoric and tetraphosphoric acids.
- 4. The process of claim 1 wherein said pH ranges from above about 3.0 to about 3.5.
Parent Case Info
This is a continuation of application Ser. No. 336,215, filed Dec. 31, 1981, now abandoned.
US Referenced Citations (4)
Continuations (1)
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Number |
Date |
Country |
Parent |
336215 |
Dec 1981 |
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