# US 4,391,714 A · Process for removing molybdenum from aqueous salt solutions

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- Number: US 4,391,714 A
- Document ID: US4391714A
- Status: Granted
- Kind: A
- Application number: 06/365,989
- Filed: 1982-04-06
- Granted: 1983-07-05
- Earliest claimed: 1981-04-10
- Assignees: Hoechst Aktiengesellschaft
- Inventors: Eberhard Preisler; Bernhard Hofmann; Johannes Holzem
- Web page: https://patentgrep.com/patent/US4391714A

## CPC

- C01G 39/003: {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
- C22B 34/34: Obtaining molybdenum {(treatment or purification of solutions by adsorption on solids C22B3/24, by liquid-liquid extraction C22B3/26, by ion-exchange extraction C22B3/42; preparation of molybdenum involving liquid-liquid extraction, adsorption or ion-exchange C01G39/003)}
- 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 disclosure relates to a process for removing molybdenum from aqueous salt solutions by adsorbing it on manganese dioxide. To this end, the salt solution is contacted with a bed of manganese dioxide (MnO.sub.2) precipitated electrolytically and transformed into granular material.

## Claims

### Claim 1

In the process for removing molybdenum from aqueous salt solutions by adsorbing it on manganese dioxide, the improvement which comprises contacting the salt solution with a bed of manganese dioxide (MnO.sub.2) precipitated electrolytically and transformed into granular material.

### Claim 2 (depends on 1)

The process as claimed in claim 1, wherein the MnO.sub.2 consists of particles with a size of 0.05 to 5 mm.

### Claim 3 (depends on 2)

The process as claimed in claim 2, wherein the MnO.sub.2 consists of particles with a size of 0.5 to 2 mm.

### Claim 4 (depends on 1)

The process as claimed in claim 1, wherein the salt solution has a pH-value of less than 4.

### Claim 5 (depends on 4)

The process as claimed in claim 4, wherein the salt solution has a pH-value of 1 to 2.5.

### Claim 6 (depends on 1)

The process as claimed in claim 1, wherein the bed of MnO.sub.2, once its adsorptive capacity is exhausted, is regenerated by draining off the salt solution and then treating the bed with an aqueous alkaline solution, the molybdenum adsorbed being ultimately removed.

### Claim 7 (depends on 6)

The process as claimed in claim 6, wherein the bed is regenerated with the use of a sodium hydroxide solution which has the concentration necessary for the solution obtained after adjustment of the desorption equilibrium to still contain at least 2 weight % free sodium hydroxide solution.

### Claim 8 (depends on 7)

The process as claimed in claim 7, wherein the solution still contains at least 5 weight % free sodium hydroxide solution.

### Claim 9 (depends on 1)

The process as claimed in claim 1, carried out at temperatures of 20.degree. to 95.degree. C.

### Claim 10 (depends on 9)

The process as claimed in claim 9, carried out at temperatures of 60.degree. to 80.degree. C.