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US3706532A Expired / Lapsed US ⏱️ 0.0 years remaining

Method for determining zinc concentration in aqueous mediums

Assignee: Veolia WTS USA Inc
•
Filing: 1971-08-20
•
Granted: 1972-12-19
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Expires: 1991-08-20
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Abstract

Abstract The present disclosure is directed to a method for determining the zinc concentration in an aqueous medium. More specifically, the method is directed for use to aqueous mediums which contain contaminated and perhaps interfering metal ions, such as the cations of aluminum, iron and copper. According to the method, the sample of the aqueous medium is acidified, treated with a buffered complexing agent to complex any aluminum and iron ions present, treated with an organo-sulfur compound which will complex with any copper ions present and discriminate against any zinc ions present. An indicator compound which will react with the zinc to produce a color has been added to the aqueous medium and the color intensity of the resulting solution is ascertained. The color intensity is then compared with the color intensity of known quantities of zinc and the indicator compound, and the concentration of the zinc is ascertained accordingly.

Inventors

  • 👤 Charles A Noll

Bibliographic Details

Application Number —
Jurisdiction US
Data Source google_patents
Last Synchronized 2026-10-23 18:00
CPC Classifications
G; G01; G01N; G01N31/00; G01N31/22; G01N31/02; Y; Y10; Y10S; Y10S422/00; Y10S422/90; Y10T; Y10T436/00; Y10T436/25; Y10T436/25125

Claims Analysis

Total Claims: 13
Claim 1
Independent Claim 27 words
A method according to claim 1 wherein the color intensity is ascertained by comparison with the color intensity of standard solutions which respectively represent known zinc concentrations.
Claim 2
Dependent Claim 23 words
A method according to claim 1 wherein the aqueous medium is alkaline and its acidity is assured by addition of a mineral acid.
Claim 3
Dependent Claim 15 words
A method according to claim 3 wherein the pH of said medium is about 6.
Claim 4
Dependent Claim 19 words
A method according to claim 1 wherein said buffered complexing agent is an alkali metal acetate-alkali metal fluoride buffer.
Claim 5
Dependent Claim 16 words
A method according to claim 1 wherein said organic sulfur copper complexing agent is 3,5-dimethyl tetrahydro-1,3,5,2H-thiadiazine-2-thione.
Claim 6
Dependent Claim 13 words
A method according to claim 1 wherein said indicator compound is xylenol orange.
Claim 7
Dependent Claim 18 words
A method according to claim 1 wherein the aqueous medium is initially filtered to remove any undissolved matter.
Claim 8
Dependent Claim 140 words
A method according to claim 1 wherein a. the buffered complexing agent contains the following ingredients on a part by weight per 25 parts by weight of aqueous medium: i. from about 0.015 to about 0.03 parts of an alkali metal fluoride, ii. from about 0.05 to about 0.3 parts of an alkali metal acetate, formate or propionate; and iii. from about 0.008 to about 0.003 parts of acetic, formic or propionic acid; b. the copper complexing agent is 3,5-dimethyl tetrahydro-1,3,5,2H-thiadiazine-2-thione and the agent is added in an amount of from about 0.003 to about 0.02 parts by weight per 25 parts by weight of said aqueous medium; and said indicator compound is xylenol orange and is added in an amount of from about 0.0015 to about 0.006 parts by weight per 25 parts by weight of said aqueous medium.
Claim 9
Dependent Claim 13 words
A method according to claim 9 wherein the aqueous medium is filtered initially.
Claim 10
Dependent Claim 19 words
A method according to claim 9 wherein the aqueous medium is a sample taken from a cooling water system.
Claim 11
Dependent Claim 13 words
A method according to claim 11 wherein the aqueous medium is filtered initially.
Claim 12
Dependent Claim 27 words
A method according to claim 9 wherein the color intensity is ascertained by comparison with the color intensity of standard solutions which respectively represent known zinc concentrations.
Claim 13
Dependent Claim 13 words
A method according to claim 13 wherein the aqueous medium is filtered initially.

References Cited (Backward Citations)

US2583891A Cited
US3479152A Cited

USPTO Annuity & Maintenance Windows

Annuity Stage Window Opens Payment Deadline Surcharge Period Until Estimated Fee Status
3.5 Years (Year 4) 1975-12-19 1976-06-19 1976-12-19 $2000.00 Window Closed / Lapsed
7.5 Years (Year 8) 1979-12-19 1980-06-19 1980-12-19 $3760.00 Window Closed / Lapsed
11.5 Years (Year 12) 1983-12-19 1984-06-19 1984-12-19 $7700.00 Window Closed / Lapsed

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