ISO 3431:1976 PDF

Name: ISO 3431:1976 — Sodium fluoride primarily used for the production of aluminium — Determination of soluble sulphates content — Turbidimetric method
SKU: ISO 3431:1976
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Sodium fluoride primarily used for the production of aluminium — Determination of soluble sulphates content — Turbidimetric method

Название (английский):

ISO 3431:1976

Sodium fluoride primarily used for the production of aluminium — Determination of soluble sulphates content — Turbidimetric method

Статус документа:: Действующий
Формат:: Электронный (PDF)
Количество страниц:: 3
Дата публикации:: 1 июля 1976 г.
Издание:: ISO IS 3431 edition 1 version 1
ICS:: 71.100.10

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Описание (английский):

Applicable to products having SO4 contents of more than 0.05 % (m/m). Covers the dissolution of the test portion in hydrochloric acid and evaporation in hydrochloric acid solution for drying. Dissolution of the residue in a hydrochloric acid solution. Measurement of the turbidity obtained by precipitation, under specified conditions, of barium sulphate using a spectrophotometer at a wavelength of about 470 nm or a photoelectric absorptiometer.

Abstract

Похожие стандарты

Стандарты, упомянутые в описании

Overview

ISO 3431:1976 specifies a turbidimetric method for determining the content of soluble sulphates (SO4) in sodium fluoride primarily used for aluminium production. The standard applies to products with soluble sulphate contents greater than 0.05% (m/m). The procedure precipitates sulphate as barium sulphate (BaSO4) and measures the resulting turbidity using a spectrophotometer or photoelectric absorptiometer at a wavelength of about 470 nm.

Key topics and technical requirements

Scope: Analytical method for soluble sulphates in industrial sodium fluoride used in aluminium manufacture; applicable when SO4 > 0.05% (m/m).

Sample preparation: Test portion is dissolved in hydrochloric acid, evaporated to dryness in hydrochloric acid solution, and the residue re-dissolved in hydrochloric acid solution (references ISO 3428 for sampling/drying).

Reagents and materials:

Hydrochloric acid (approx. 38% / ~12 N and ~1 N solutions)
Calibrated barium chloride dihydrate (specified particle size)
Standard sulphuric acid solution (equivalent to 0.200 g SO4 per litre)
Glycerine and an acidic sodium chloride solution (240 g/L)

Turbidimetric reaction:

Precipitation of BaSO4 by adding a measured amount of BaCl2 to aliquots of the prepared sample solution
Manual agitation for 1 minute (two turns per second), then letting the suspension rest for 20 minutes at 20 ± 2 °C

Measurement and calibration:

Turbidity measured at ~470 nm with matched cuvettes
Calibration curve constructed from standard SO4 solutions (blank corrections and compensation solution required)
If turbidity exceeds calibration range, dilution and re‑analysis with appropriate compensation are specified

Results expression: Sulphate content reported as mg or percentage (m/m) SO4 based on calibration and blank corrections; test report must list method reference, results and any deviations.

Applications and users

Industrial quality control in aluminium production where sodium fluoride is used as a flux or raw material

Chemical and analytical laboratories responsible for incoming material inspection and specification compliance

Producers and suppliers of sodium fluoride who must certify soluble sulphate levels

Regulatory and standards bodies checking conformity to ISO requirements

Keywords: ISO 3431, sodium fluoride, soluble sulphates, turbidimetric method, BaSO4 precipitation, spectrophotometer, aluminium production, analytical method.

Related standards

ISO 3428 - Preparation and storage of samples for testing

ISO 3429 - Iron determination (related analyses)

ISO 3430 - Silica determination

ISO 3566 - Chloride determination, turbidimetric method

ISO 4278 - Carbonate determination (gravimetric)

ISO 2831 / 2832 / 2833 - Other sodium fluoride test methods and properties

ISO 3431:1976 PDF

Abstract

Похожие стандарты

Overview

Key topics and technical requirements

Applications and users

Related standards

Технические детали

ISO 3428:1976

Sodium fluoride for industrial use — Preparation and storage of test samples

ISO 3429:1976

Sodium fluoride primarily used for the production of aluminium — Determination of iron content — 1,10- Phenan…

ISO 3430:1976

Sodium fluoride primarily used for the production of aluminium — Determination of silica content — Reduced mo…

ISO 3566:1976

Sodium fluoride primarily used for the production of aluminium — Determination of chlorides content — Turbidi…

ISO 4278:1977

Sodium fluoride for industrial use — Determination of carbonate content — Gravimetric method

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