# US 4,399,037 A · Process for working up waste water containing phosphorus

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- Number: US 4,399,037 A
- Document ID: US4399037A
- Status: Granted
- Kind: A
- Application number: 06/308,424
- Filed: 1981-10-05
- Granted: 1983-08-16
- Earliest claimed: 1980-10-10
- Assignees: Hoechst Aktiengesellschaft
- Inventors: Herbert Diskowski; Johannes Krause; Dietrich Mandelkow
- Web page: https://patentgrep.com/patent/US4399037A

## CPC

- C02F 1/385: {by centrifuging suspensions (centrifuges B04B)}
- C02F 1/66: by neutralisation; pH adjustment (for degassing C02F1/20; using ion-exchange C02F1/42; for flocculation or precipitation of suspended impurities C02F1/52; for removing dissolved compounds C02F1/58)
- C02F 1/74: with air (aeration of stretches of water C02F7/00)
- C02F 2103/34: from industrial activities not provided for in groups C02F2103/12 - C02F2103/32
- Y10S 210/906: Phosphorus containing
- C02F: TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE (separation in general B01D; special arrangements on waterborne vessels of installations for treating water, waste water or sewage, e.g. for producing fresh water, B63J; adding materials to water to prevent corrosion C23F; treating radioactively-contaminated liquids G21F9/04; regeneration of reactants for recirculation into processes, see the relevant places for the processes)
- Y10S: TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS

## Abstract

The invention relates to a process for working up phosphorus-containing waste water by subjecting it to filtration with the use of a filter aid in a centrifugal filter. To this end, waste water with a temperature of at least 46.degree. C. and a pH-value within the range 0.5 to 4.0 is introduced into the centrifugal filter and fitrate coming from the centrifugal filter is introduced into a calming zone and separated therein within an average period of 10 to 60 minutes into yellow phosphorus and water containing 1 to 30 ppm of phosphorus. Water overflowing from the calming zone is treated with an oxidant and the waste water so freed from phosphorus is reacted with a neutralizing agent.

## Claims

### Claim 1

A process for working up phosphorus-containing waste water obtained in the electrothermal production of phosphorus by subjecting it to filtration with the use of a filter aid in a centrifugal filter, which comprises: introducing the waste water with a temperature of at least 46.degree. C. and a pH-value of at least 0.5 but less than 4.0 into the centrifugal filter; introducing filtrate coming from the centrifugal filter into a calming zone and separating it therein with an average period of 10 to 60 minutes into yellow phosphorus and water containing 1 to 30 ppm of phosphorus; treating water overflowing from the calming zone with an oxidant; and neutralizing the waste water so freed from phosphorus with calcium metasilicate.

### Claim 2 (depends on 1)

A process as claimed in claim 1, wherein the waste water introduced into the centrifugal filter has a temperature of 50.degree. to 75.degree. C.

### Claim 3 (depends on 2)

A process as claimed in claim 2, wherein the waste water has a temperature of 60.degree. to 70.degree. C.

### Claim 4 (depends on 1)

A process as claimed in claim 1, wherein the waste water introduced into the centrifugal filter has a pH-value within the range 2.0 and 3.5.

### Claim 5 (depends on 1)

A process as claimed in claim 1, wherein air is used as the oxidant.

### Claim 6 (depends on 1)

A process as claimed in claim 1, wherein a bleaching liquor is used as the oxidant.

### Claim 7 (depends on 1)

A process as claimed in claim 1, wherein phosphorus furnace slag is used as calcium metasilicate.