# US 4,396,585 A · Silver removal with halogen impregnated non-carbon adsorbents

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- Number: US 4,396,585 A
- Document ID: US4396585A
- Status: Granted
- Kind: A
- Application number: 06/305,890
- Filed: 1981-09-28
- Granted: 1983-08-02
- Earliest claimed: 1981-09-28
- Assignees: Calgon Carbon Corporation
- Inventors: Michael R. Rosene
- Web page: https://patentgrep.com/patent/US4396585A

## CPC

- C01G 5/003: {Preparation involving a liquid-liquid extraction, an adsorption or an ion-exchange}
- C22B 3/24: by adsorption on solid substances, e.g. by extraction with solid resins
- Y02P 10/20: Recycling
- C01G: COMPOUNDS CONTAINING METALS NOT COVERED BY SUBCLASSES C01D OR C01F (metal hydrides {monoborane, diborane or addition complexes thereof} C01B6/00; salts of oxyacids of halogens C01B11/00; peroxides, salts or peroxyacids C01B15/00; thiosulfates, dithionites, polythionates C01B17/64; compounds containing selenium, or tellurium C01B19/00; binary compounds of nitrogen with metals C01B21/06; azides C01B21/08; {compounds containing nitrogen, other non-metals and metal C01B21/082}; metal amides C01B21/092; nitrites C01B21/50; {compounds of noble gases C01B23/0005}; phosphides C01B25/08; salts of oxyacids of phosphorus C01B25/16; carbides C01B32/90; compounds containing silicon C01B33/00; compounds containing boron C01B35/00; compounds having molecular sieve properties but not having base-exchange properties C01B37/00; compounds having molecular sieve and base-exchange properties, e.g. crystalline zeolites, C01B39/00; cyanides C01C3/08; salts of cyanamide C01C3/16; thiocyanates C01C3/20)
- C22B: PRODUCTION AND REFINING OF METALS (electrolytic C25); PRETREATMENT OF RAW MATERIALS
- Y02P: CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS

## Abstract

The removal of silver from photographic and other solutions using a non-carbon halogen impregnated adsorbent is described.

## Claims

### Claim 1

A process for removing ionic silver from a solution comprising contacting said solution with a halogen impregnated non-carbon adsorbent selected from natural zeolites, synthetic zeolites, activated alumina, activated silica Fuller's earth, bentonite clay, and hectorite clay, said adsorbent containing at least 0.1 weight percent halogen, said halogen being selected from the group consisting of iodine, bromine, chlorine or any combination of iodine, bromine and chlorine.

### Claim 2 (depends on 1)

The process of claim 1 wherein the adsorbent contains from about 5 to 50 weight percent of iodine, bromine or chlorine, or any combination of iodine bromine, or chlorine.

### Claim 3 (depends on 2)

The process of claim 2 wherein the adsorbent contains about 10 weight percent of iodine, bromine or chlorine or any combination of iodine bromine, or chlorine.

### Claim 4 (depends on 3)

The process of claim 3 which further comprises contacting said solution and said adsorbent up to breakthrough, and wherein said ionic silver is the aqueous photographic silver-thiosulfate complex.

### Claim 5 (depends on 4)

The process of claim 4 wherein the aqueous silver-thiosulfate complex concentration is less than 500 ppm.

### Claim 6 (depends on 1, 2, 3, 4)

The process of claims 1 or 2 or 3 or 4 wherein the halogen is iodine.