REMOVAL AND SEPARATION OF METALLIC OXIDE SCALE

• US 3,664,870 A
• Filed: 10/29/1969
• Issued: 05/23/1972
• Est. Priority Date: 10/29/1969
• Status: Expired due to Term

• Current Assignee: Alfred W. Oberhofer, Charles C. Payne, Donald R. Anderson
• Original Assignee: Alfred W. Oberhofer, Charles C. Payne, Donald R. Anderson
• Inventors: Anderson, Donald R., Payne, Charles C., Oberhofer, Alfred W.
• Primary Examiner(s): Wolk, Morris O.
• Assistant Examiner(s): Zatarga, Joseph T.
• Application Number:
  US04/872,411
• Time in Patent Office: 937 Days
• Field of Search: 134/3,22,10,13,27,28,29,41 210/38
• US Class Current: 134/3
• CPC Class Codes: C23G 1/088 solutions containing organic acids
• CPC Class Codes: C23G 1/36 Regeneration of waste pickling liquors

Abstract

A method of removing metallic oxide scale from the cooling system of a nuclear reactor is disclosed. By forming complexes of the metals using ammoniated citric acid, the scale can be removed. By selectively adsorbing these complexes on ion exchange resins the scale can be separated.

Claims

2. The method of claim 1 in which the scale is the crud from a nuclear reactor cooling system.

3. The method of claim 2 in which an oxidant selected from the group consisting of sodium nitrate, ammonium persulfate, ammonium perborate, and hydrogen peroxide is added after the pH is adjusted to from 9-11 with ammonia to enhance the dissolution of the copper.

4. The method of claim 3 including the additional step of:

regenerating the ion exchange resins using a compound selected from the group consisting of mineral acids, and salts of mineral acids.

5. The method of claim 4 including the additional step of:

treating the anion exchange resin with sodium hydroxide after regeneration.