ISO 2124-1972 PDF

Full title and description

ISO 2124:1972 — Sodium and potassium silicates for industrial use — Determination of silica content — Titrimetric method. This short method specifies a titrimetric procedure for determining silica (SiO2) in industrial sodium and potassium silicate products by chemical insolubilization and titration of excess acid.

Abstract

The method neutralizes the alkalinity of a dissolved test portion in the presence of methyl red, adds sodium fluoride to convert silicic acid into an insoluble silicic compound, treats the mixture with a measured excess of standardized hydrochloric acid (with ethanol for dilution), filters off the insoluble silica compound, and titrates the excess HCl in the filtrate with standard NaOH (methyl red indicator). The procedure is presented in a concise two-page format in the original ISO publication.

General information

• Status: Withdrawn (International Standard).
• Publication date: June 1972 (Edition 1).
• Publisher: International Organization for Standardization (ISO).
• ICS / categories: 71.060.50 (Salts, inorganic chemicals).
• Edition / version: Edition 1 (1972).
• Number of pages: 2 pages (concise test method).

Scope

Specifies a titrimetric procedure for the determination of silica content in industrial sodium and potassium silicates. Intended for routine laboratory quality-control testing of liquid and soluble silicate products where a titrimetric insolubilization approach is appropriate. The method addresses sample dissolution, reagent addition (including NaF), formation and separation of an insoluble silicic compound, and back-titration of excess acid.

Key topics and requirements

• Principle: insolubilization of silicic acid (using fluoride) followed by filtration and titration of excess acid.
• Reagents and indicators: standardized hydrochloric acid, sodium fluoride (NaF), standard sodium hydroxide, methyl red as indicator, ethanol for dilution.
• Sample handling: dissolution of the test portion and control of alkalinity prior to insolubilization.
• Analytical steps: controlled addition of reagents, filtration/collection of insoluble silica compound, blank determination, and calculation of silica content from titration results.
• Reporting: silica content expressed as mass percentage (SiO2) using the titrimetric calculations defined in the method.

Typical use and users

Quality-control and analytical laboratories in manufacturers of sodium and potassium silicates, chemical suppliers, formulation plants (e.g., detergents, adhesives, construction chemicals), and regulatory or third‑party testing bodies. The method is suitable where a rapid titrimetric approach is preferred over gravimetric or spectrometric alternatives.

Related standards

Relevant and neighboring ISO standards covering test methods and calculations for silicates and related determinations include ISO 2122:1972 (preparation of solutions and determination of matter insoluble in water), ISO 1690:1976 (gravimetric determination of silica by insolubilization — alternative gravimetric procedure), ISO 1692:1976 (determination of total alkalinity), ISO 1689:1976 (calculation of SiO2/Na2O or SiO2/K2O ratios), and other ISO methods for silica determination in alkalis and related materials. Note that ISO 2124 itself is withdrawn; laboratories frequently use ISO 1690 or other contemporary methods where appropriate.

Keywords

sodium silicate, potassium silicate, silica determination, SiO2, titrimetric method, insolubilization, sodium fluoride, methyl red, ISO 2124, industrial silicates, quality control.

FAQ

Q: What is this standard?

A: ISO 2124:1972 is an ISO test method titled "Sodium and potassium silicates for industrial use — Determination of silica content — Titrimetric method," published in June 1972. It is a concise (2-page) analytical procedure.

Q: What does it cover?

A: It covers a titrimetric procedure based on neutralization, addition of sodium fluoride to form an insoluble silicic compound, filtration of that compound, and back-titration of excess hydrochloric acid with sodium hydroxide using methyl red as indicator; used to quantify SiO2 in industrial silicates.

Q: Who typically uses it?

A: Chemical and QC laboratories at manufacturers and suppliers of sodium/potassium silicates, formulation plants (detergent, construction chemicals, adhesives), and testing bodies performing routine compositional analysis.

Q: Is it current or superseded?

A: ISO 2124:1972 has been withdrawn (ISO record shows the standard is withdrawn; national catalogues indicate withdrawal action in 2002). Users should consult current ISO methods for silica determination (for example ISO 1690:1976 for a gravimetric insolubilization method and other more recent analytical standards) when selecting an up‑to‑date procedure.

Q: Is it part of a series?

A: Yes — ISO 2124 was published alongside a set of ISO methods addressing sodium and potassium silicates (e.g., ISO 2122, ISO 2123) and is conceptually related to later ISO documents (ISO 1689, ISO 1690, ISO 1692, ISO 1688) that address other analytical determinations and calculations for silicates.

Q: What are the key keywords?

A: SiO2, silica content, sodium silicate, potassium silicate, titrimetric, insolubilization, sodium fluoride, methyl red, hydrochloric acid, back‑titration.