# US 5,705,077 A · Method of controlling fluoride scale formation in aqueous systems

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- Number: US 5,705,077 A
- Document ID: US5705077A
- Status: Granted
- Kind: A
- Application number: 08/594,220
- Filed: 1996-01-31
- Granted: 1998-01-06
- Earliest claimed: 1996-01-31
- Assignees: BetzDearborn Inc.
- Inventors: Jennifer J. Robertson
- Web page: https://patentgrep.com/patent/US5705077A

## CPC

- C02F 5/10: using organic substances
- 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)

## Abstract

A method of treating water to inhibit the formation of fluoride salt scale is disclosed. The method is particularly effective at inhibiting the formation and deposition of fluoride containing salts in spray water cooling systems such as steel casting systems. The method comprises introducing into the aqueous system a polyepoxysuccinic acid of the general formula: ##STR1## where n ranges from about 2 to about 11, M is hydrogen or a water soluble cation such as Na.sup.+, NH.sub.4.sup.+ or K.sup.+ and R is hydrogen, C.sub.1-4 alkyl or C.sub.1-4 substituted alkyl.

## Claims

### Claim 1

A method of controlling the formation and deposition of fluoride salt scale in a caster spray water system containing calcium and fluoride ions comprising introducing into said system a substoichiometric amount sufficient for the purpose of a treatment comprising a polyepoxysuccinic acid of the general formula: ##STR5## wherein n ranges from about 2 to about 50, M is hydrogen or a water soluble cation and R is hydrogen, C.sub.1-4 alkyl or C.sub.1-4 substituted alkyl.

### Claim 2 (depends on 1)

The method as recited in claim 1 wherein said fluoride salt is calcium fluoride.

### Claim 3 (depends on 1)

The method as recited in claim 1 wherein M is selected from the group consisting of Na.sup.+, NH.sub.4.sup.+, and K.sup.+.

### Claim 4 (depends on 1)

The method as recited in claim 1 wherein said polyepoxysuccinic acid is added to the caster spray water system at active treatment levels ranging from about 25 parts per billion to about 500 parts per million.

### Claim 5 (depends on 4)

The method as recited in claim 4 wherein said polyepoxysuccinic acid is added to the caster spray water system at active treatment levels ranging from about 50 parts per billion to about 100 parts per million.

### Claim 6 (depends on 1)

The method as recited in claim 1 wherein n ranges from about 2 to about 25.

### Claim 7

A method of controlling the formation and deposition of fluoride salt scale in a steel casting spray water system comprising adding to said steel casting spray water system containing calcium and fluoride ions a substoichometric amount sufficient for the purpose of a treatment comprising a polyepoxysuccinic acid of the general formula: ##STR6## wherein n ranges from about 2 to about 50, M is hydrogen or a water soluble cation and R is hydrogen, C.sub.1-4 alkyl or C.sub.1-4 substituted alkyl.

### Claim 8 (depends on 7)

The method as recited in claim 7 wherein said fluoride salt is calcium fluoride.

### Claim 9 (depends on 7)

The method as recited in claim 7 wherein M is selected from the group consisting of Na.sup.+, NH.sub.4.sup.+, and K.sup.+.

### Claim 10 (depends on 7)

The method as recited in claim 7 wherein said polyepoxysuccinic acid is added to the steel casting spray water system at active treatment levels ranging from about 25 parts per billion to about 500 parts per million.

### Claim 11 (depends on 10)

The method as recited in claim 10 wherein said polyepoxysuccinic acid is added to the steel casting spray meter system at active treatment levels ranging from about 50 parts per billion to about 100 parts per million.

### Claim 12 (depends on 7)

The method as recited in claim 7 wherein n ranges from about 2 to about 25.