EP0068411A2
Expired / Lapsed
EP
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Method of selectively removing adsorbed calcium and magnesium from cation exchange resins
Assignee: American Petro Mart Inc
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Filing: 1982-06-22
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Granted: —
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Expires: 2002-06-22
Abstract
Abstract Adsorbed calcium is selectively removed from cation exchange resins in the presence of adsorbed magnesium by eluting the resin with aqueous sulfuric acid saturated with CaSO 4 and undersaturated with MgS0 4 to obtain a solution supersaturated with CaSO 4 from wich the CaSO 4 can be readily precipitated. The magnesium is subsequently removed from the resin by eluting with aqueous sulfuric acid, such as 20-70% H 2 SO 4 . The method is advantageously used in the regeneration of cation exchange resins, such as the loaded resins used for treatment of phosphate rock-derived phosphoric acid.
Inventors
- 👤 Solon Gene Whitney
- 👤 William Richard Erickson
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-29 16:47
CPC Classifications
C; C01; C01F; C01F11/00; C01F11/46; B; B01; B01D; B01D15/00; B01D15/08; B01J; B01J49/00; B01J49/10; B01J49/12; B01J49/50; B01J49/53; C01F5/00; C01F5/40; C22; C22B; C22B3/00; C22B3/20; C22B3/42; Y; Y02; Y02P; Y02P10/00; Y02P10/20
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
137 words
The method of selectively removing calcium from cation exchange resin beads containing adsorbed calcium and magnesium ions, characterized by the steps of: (a) passing an aqueous sulfuric acid (H 2 SO 4 ) solution through a bed of said resin beads, said solution having an H 2 SO 4 concentration of from 20 to 50% by weight, being saturated with calcium sulfate (CaSO 4 ), and containing magnesium sulfate (MgSO 4 ) at a concentration substantially below saturation; (b) continuing to pass said solution through said resin bed until the adsorbed magnesium is in ion exchange equilibrium with the magnesium in solution while simultaneously exchanging the hydrogen ions in solution for the adsorbed calcium ions, said solution becoming supersaturated with calcium sulfate; and (c) passing the said supersaturated solution to a crystallizer and precipitating CaSO 3 therein.
Claim 2
Independent Claim
137 words
The method of selectively removing calcium from cation exchange resin beads containing adsorbed calcium and magnesium ions, characterized by the steps of: (a) passing an aqueous sulfuric acid (H 2 SO 4 ) solution through a bed of said resin beads, said solution having an H 2 SO 4 concentration of from 20 to 50% by weight, being saturated with calcium sulfate (CaSO 4 ), and containing magnesium sulfate (MgSO 4 ) at a concentration substantially below saturation; (b) continuing to pass said solution through said resin bed until the adsorbed magnesium is in ion exchange equilibrium with the magnesium in solution while simultaneously exchanging the hydrogen ions in solution for the adsorbed calcium ions, said solution becoming supersaturated with calcium sulfate; and (c) passing the said supersaturated solution to a crystallizer and precipitating CaSO 3 therein.
Claim 3
Dependent Claim
26 words
The method of claim 1 further characterized in that said solution has an H 2 SO 4 concentration of from about 25% to 40% by weight.
Claim 4
Independent Claim
29 words
The method of claims 1 and 2 further characterized in that said method steps are continued until at least 50% of the adsorbed calcium is removed from said resin.
Claim 5
Dependent Claim
36 words
The method of claim 1, 2 and 3 further characterized in that the H 2 SO 4 solution in said crystallizer after said precipitation of CaSO4 therefrom is recycled to said resin bed and passed therethrough.
Claim 6
Independent Claim
63 words
The method of claims 1, 2 and 3 further characterized in that the H 2 SO 4 solution in said crystallizer after said precipitation of CaSO 4 therefrom is recycled through said resin bed for further removal of adsorbed calcium, said recycling being continued until at least 75% of the adsorbed calcium has been removed while leaving the adsorbed magnesium in said beads.
References Cited (Backward Citations)
No citation records indexed.
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