ISO 4278-1977 PDF

Full title and description

ISO 4278:1977 — Sodium fluoride for industrial use — Determination of carbonate content — Gravimetric method. This International Standard specifies a gravimetric analytical procedure for measuring the carbonate content (expressed as Na2CO3) in sodium fluoride intended for industrial use.

Abstract

The standard describes a gravimetric method applicable to sodium fluoride products with carbonate contents greater than 0.02 % (m/m). The procedure releases carbon dioxide from a test portion by acidification and heating, entrains the CO2 in a stream of air, absorbs it in weighed absorption tubes containing soda‑asbestos, and determines carbonate content by weighing the uptake. An erratum to the published text was issued after initial publication.

General information

• Status: Withdrawn (withdrawal stage recorded by ISO).
• Publication date: November 1977 (First edition: 1977-11-01).
• Publisher: International Organization for Standardization (ISO).
• ICS / categories: 71.060.50 (Analytical chemistry / Inorganic substances).
• Edition / version: Edition 1 (1977).
• Number of pages: 6 pages.

(ISO bibliographic and lifecycle details as recorded by ISO/TC and the ISO catalogue.)

Scope

Specifies a gravimetric determination of carbonate in sodium fluoride for industrial use; intended for samples where carbonate (reported as sodium carbonate) exceeds 0.02 % by mass. The method covers apparatus, reagents, sample preparation, procedure (acidification/heating, CO2 entrainment and absorption) and calculation of carbonate content.

Key topics and requirements

• Analytical principle: release of CO2 by acidification and heating of a test portion, entrainment of CO2 in an air stream and absorption in pre‑weighed tubes for gravimetric determination.
• Applicability: intended for industrial sodium fluoride with carbonate content > 0.02 % (m/m).
• Apparatus: specified distillation/absorption assembly including a 250 ml flask with plunging adaptor, absorption tubes charged with soda‑asbestos and auxiliary absorption tubes for moisture/impurities.
• Reagents and calibration: defined reagents and blank corrections; gravimetric weighing procedure and calculation steps are provided in the text.
• Published erratum: corrections to minor wording and clause details were published as an erratum after initial release.
• Lifecycle note: the standard has been recorded as withdrawn in the ISO catalogue (withdrawal stage). Users should confirm alternative methods or more recent standards for routine analysis.

Typical use and users

Primary users include industrial chemistry laboratories, quality control and production laboratories in companies handling sodium fluoride (e.g., producers of fluorides, metal‑processing industries using fluoride fluxes), and testing/inspection bodies that historically required carbonate determination in sodium fluoride. Analytical chemists and laboratory technicians performing gravimetric inorganic analyses would apply the procedure when this method is required by a specification.

Related standards

ISO 4278 sits among other ISO standards for fluorides and related materials (examples from the same numeric block include ISO 4279:1977 and ISO 4280:1977). The method references sample preparation standards such as ISO 3428 (preparation and preservation of test samples for sodium fluoride). Note: several standards in this group have been subject to withdrawal or replacement—verify the current status of any related method before use.

Keywords

sodium fluoride; carbonate; Na2CO3; gravimetric method; carbon dioxide absorption; soda‑asbestos; analytical chemistry; ISO 4278:1977.

FAQ

Q: What is this standard?

A: ISO 4278:1977 is an International Standard that specified a gravimetric method for determining the carbonate content of sodium fluoride intended for industrial use.

Q: What does it cover?

A: It covers the scope, principle, apparatus, reagents, step‑by‑step procedure (acidification, heating, CO2 entrainment and absorption), and calculation for reporting carbonate content expressed as sodium carbonate for samples with carbonate > 0.02 % (m/m). An erratum was published to correct editorial/wording issues.

Q: Who typically uses it?

A: Analytical chemists, laboratory technicians, and quality-control personnel in industries producing or using sodium fluoride — plus testing and inspection laboratories — historically used this method when specified by product requirements or contracts.

Q: Is it current or superseded?

A: ISO 4278:1977 is recorded as withdrawn in the ISO catalogue. Public listings indicate it was withdrawn and is not shown as having a direct replacement; users should consult current ISO catalogues or national standards bodies for any more recent or alternative methods.

Q: Is it part of a series?

A: It belongs numerically to a group of ISO methods addressing analysis of fluorides, cryolite and related materials (ISO 4279, ISO 4280, ISO 4281, etc.), many of which were prepared by ISO technical committees dealing with chemistry and materials for aluminium production. Verify the status of adjacent standards for current applicability.

Q: What are the key keywords?

A: Key terms include sodium fluoride, carbonate, Na2CO3, gravimetric analysis, carbon dioxide absorption, soda‑asbestos, analytical procedure, and ISO 4278:1977.