Processes for making rare earth metal oxycarbonates
Rare earth metal compounds, particularly lanthanum, cerium, and yttrium, are formed as porous particles and are effective in binding metals, metal ions, and phosphate. A method of making the particles and a method of using the particles is disclosed. The particles may be used in the gastrointestinal tract or the bloodstream to remove phosphate or to treat hyperphosphatemia in mammals. The particles may also be used to remove metals from fluids such as water.
1 . A process for making a rare earth metal oxycarbonate, wherein the process comprises the following steps:
a) making a solution of rare earth chloride;
b) subjecting the solution to a feed of sodium carbonate solution at a temperature between about 30° C. and about 90° C. while mixing to form a precipitate;
c) filtering and washing the precipitate to form a filter cake; and,
d) drying the filter cake
thereby making a rare earth metal oxycarbonate.
2 . The process according to claim 1 , wherein the rare earth chloride is lanthanum chloride.
3 . The process according to claim 1 , wherein the rare earth metal oxycarbonate is a hydrate, and wherein the filter cake is dried at a temperature of about 100° C. to 120° C.
4 . The process according to claim 1 , wherein the rare earth metal oxycarbonate is anhydrous, and wherein the filter cake is dried at a temperature between about 400° C. and about 700° C.
5 . The process according to claim 1 , wherein the process further comprises:
a) slurrying the filter cake; and,
b) subsequently milling the filter cake in a horizontal or vertical pressure media mill to a desired surface area.
6 . The process according to claim 2 , wherein the rare earth metal oxycarbonate is a hydrate, and wherein the filter cake is dried at a temperature of about 100° C. to 120° C.
7 . The process according to claim 2 , wherein the rare earth metal oxycarbonate is anhydrous, and wherein the filter cake is dried at a temperature between about 400° C. and about 700° C.
8 . The process according to claim 6 , wherein the process further comprises:
a) slurrying the filter cake; and,
b) subsequently milling the filter cake in a horizontal or vertical pressure media mill to a desired surface area.
9 . The process according to claim 7 , wherein the process further comprises:
a) slurrying the filter cake; and,
b) subsequently milling the filter cake in a horizontal or vertical pressure media mill to a desired surface area.
10 . The process according to claim 8 , wherein the process further comprises drying the milled filter cake to form a powder.
11 . The process according to claim 9 , wherein the process further comprises drying the milled filter cake to form a powder.