Claims
- 1. A process for the production of alkali metal phosphates and aluminium trihydrate from phosphate rock which contains calcium phosphate, iron phosphate and aluminum phosphate comprising leaching the rock with a solution containing alkali metal hydroxide and alkali metal carbonate to produce a solution containing aluminium trihydrate and alkali metal phosphates, recovering the aluminum trihydrate and alkali metal phosphates from the solution, calcining the residual solids from the leaching step with alkali metal carbonate, leaching the calcined material to yield alkali metal orthophosphates in solution and recovering the orthophosphates by cooling the solution to crystallize the orthophosphates.
- 2. A process as in claim 1 wherein the calcined material is leached with an aqueous solution of alkali metal carbonate containing carbon dioxide.
- 3. A process for production of alkali metal phosphates from naturally occurring phosphate rock containing calcium, iron, and aluminium phosphates in such amount that the total content of iron and aluminum, calculated as Fe.sub.2 O.sub.3 and Al.sub.2 O.sub.3 respectively, is greater than 5% by weight of said material, in which the rock is first leached with alkali metal hydroxides and carbonates to produce a solution containing aluminum trihydrate and alkali metal phosphates, said aluminium trihydrate and alkali metal phosphates are recovered from the solution and the residual solids are calcined with alkali metal carbonate, the calcined material being then leached to yield alkali metal orthophosphates in solution.
- 4. A process for production of alkali metal phosphates from naturally occurring phosphate rock containing calcium, iron, and aluminum phosphates in such amount that the total content of iron and aluminum, calculated as Fe.sub.2 O.sub.3 and Al.sub.2 O.sub.3 respectively, is greater than 5% by weight of said material, in which the rock is first leached with alkali metal hydroxides and carbonates to produce a solution containing aluminium trihydrate and alkali metal phosphates, the leach solution is cooled and said aluminium trihydrate and alkali metal phosphates are recovered from the solution by crystallization, and the residual solids are recycled and calcined with alkali metal carbonate to recover the phosphate therein.
Priority Claims (3)
Number |
Date |
Country |
Kind |
PF9977 |
Jun 1983 |
AUX |
|
PG0279 |
Jul 1983 |
AUX |
|
PG1294 |
Sep 1983 |
AUX |
|
Parent Case Info
This is a continuation of application Ser. No. 621,730, filed June 18, 1984, which was abandoned upon the filing hereof.
US Referenced Citations (6)
Foreign Referenced Citations (5)
Number |
Date |
Country |
296022 |
Jul 1929 |
GBX |
389359 |
Mar 1933 |
GBX |
908021 |
Oct 1962 |
GBX |
1159660 |
Jul 1969 |
GBX |
1403155 |
Aug 1975 |
GBX |
Continuations (1)
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Number |
Date |
Country |
Parent |
621730 |
Jun 1984 |
|