ISO 334-2020 PDF

Full title and description

ISO 334:2020 — Coal and coke — Determination of total sulfur — Eschka method. This International Standard specifies a reference laboratory method (the Eschka method) for determining the total sulfur content of hard coal, brown coals and lignites, and coke.

Abstract

This document specifies a reference method for determining the total sulfur content of hard coal, brown coals and lignites, and coke by the Eschka method. The procedure converts sulfur to sulfate during ignition with an Eschka mixture, followed by acid extraction and gravimetric determination of sulfate as barium sulfate (BaSO4). The method is intended as a reference against which alternative or instrumental methods can be validated.

General information

• Status: Published (current).
• Publication date: 5 August 2020 (Edition 4, published August 2020).
• Publisher: International Organization for Standardization (ISO).
• ICS / categories: 73.040 (Coals); 75.160.10 (Solid fuels).
• Edition / version: 4 (2020).
• Number of pages: 7.

Scope

ISO 334:2020 provides a reference laboratory procedure (Eschka method) for the determination of total sulfur in hard coal, brown coals (lignite) and coke. It is intended for routine and reference analyses where a gravimetric determination of total sulfur is required and for use when validating alternative analytical methods for sulfur in these solid fuels.

Key topics and requirements

• Principle: conversion of sulfur to sulfate by ignition with Eschka mixture, extraction with hydrochloric acid, and gravimetric determination of sulfate as barium sulfate (BaSO4).
• Eschka mixture composition and preparation: typically two parts light calcined magnesium oxide to one part anhydrous sodium (or potassium) carbonate, sieved to specified particle size.
• Test portion and sample preparation: reduction of sample to specified particle size (usually passing 212 µm) and selection of test portion mass according to expected sulfur content.
• Ignition conditions: controlled muffle-furnace ignition (nominally 800 °C ± 25 °C) in an oxidizing atmosphere with defined furnace and crucible requirements.
• Apparatus: muffle furnace, suitable crucibles (porcelain, silica, or other specified materials), Gooch or equivalent filtration crucibles, analytical balance with appropriate readability.
• Analytical steps: weighing and mixing sample with Eschka mixture, stepwise ignition schedule, acid extraction of residues, filtration and washing, neutralization, controlled precipitation with barium chloride, ignition/drying of BaSO4 and gravimetric weighing.
• Quality and validation: provision of repeatability/reproducibility information and recommendation that instrumental or alternative methods be validated against this reference method to demonstrate lack of bias.
• Applicability: intended for hard coal, brown coal/lignite and coke; procedural notes and limits for adapting test portion mass and conditions for different sulfur ranges.

Typical use and users

ISO 334:2020 is used by analytical laboratories, coal and coke producers, fuel testing facilities, buyers and sellers in the coal trade, environmental and regulatory laboratories, and research institutions. Typical uses include quality control of fuel consignments, contract verification, method validation for instrumental sulfur determinations, and reference testing where traceability to a gravimetric method is required.

Related standards

Standards commonly referenced alongside ISO 334 include earlier or complementary ISO methods for coal and coke analysis such as ISO 351 (high-temperature combustion methods for total sulfur), ISO 157 (determination of forms of sulfur), ISO 19579 (sulfur by IR spectrometry), ISO 17246 (proximate analysis), ISO 1928 (calorific value), ISO 1171 (ash), ISO 17247 (ultimate analysis) and ISO 29541 (instrumental determination of C, H, N). ISO 334:2020 replaces ISO 334:2013.

Keywords

coal, coke, total sulfur, Eschka method, Eschka mixture, barium sulfate, gravimetric determination, solid fuels, ISO/TC 27/SC 5, fuel analysis, reference method

FAQ

Q: What is this standard?

A: ISO 334:2020 is an International Standard that specifies the Eschka reference method for determining total sulfur in hard coal, brown coal (lignite) and coke.

Q: What does it cover?

A: It covers sample preparation, Eschka mixture composition, ignition and extraction procedures, precipitation and gravimetric determination of sulfate as BaSO4, apparatus and conditions, and provides guidance on test portion selection, repeatability/reproducibility and method validation.

Q: Who typically uses it?

A: Analytical laboratories, coal and coke producers, fuel traders, environmental and regulatory agencies, and research institutions that require a gravimetric reference method for total sulfur analysis or need to validate alternative/instrumental methods.

Q: Is it current or superseded?

A: ISO 334:2020 is the current (published) edition, Edition 4, published in August 2020. It replaces ISO 334:2013. The standard is subject to periodic review by ISO (standard review cycle information indicates review activity and potential future revision).

Q: Is it part of a series?

A: ISO 334 is part of the suite of ISO standards for analysis of coal and coke maintained by ISO/TC 27/SC 5. It complements related standards for proximate and ultimate analysis, forms of sulfur, and alternative sulfur determination methods.

Q: What are the key keywords?

A: Coal, coke, total sulfur, Eschka method, Eschka mixture, BaSO4, gravimetric, solid fuels, reference method.