🔥 Chlorine in hard coal, brown coal and coke — combustion with Eschka mixture, determination by the Volhard method, the Mohr method or potentiometric titration with an ion-selective electrode; PN-ISO 587:2000

Petrochemistry PN-ISO 587

Overview

WHAT THE STANDARD COVERS. Scope from the PKN card of PN-ISO 587:2000, in full (our translation): "A method for the determination of the chlorine content of hard coal, brown coal and coke using Eschka mixture is given. The principle of the method, the combustion procedure and the performance of the determination by the Volhard and Mohr methods and by the method of potentiometric titration using an ion-selective electrode are described. The reagents, the apparatus, the preparation of the test sample and the calculation of results are also given" (no full stop on the card). Scope of ISO 587:2020 according to the evs.ee catalogue, in full: "This document specifies a method of determining the chlorine content of hard coal, brown coals and lignites, and coke using Eschka mixture." We did not have the text of either edition — we do not know the composition of the Eschka mixture according to the standard, the temperature and time of combustion or the course of any of the three determinations.

STATUS (as of 08.10.2026). The PKN card of PN-ISO 587:2000 (Polish version) does not have the label "Withdrawn": title "Solid fuels -- Determination of chlorine content using Eschka mixture" (our translation), publication 24-02-2000, 12 pages, price group F, Mining Sector, KT 220 Natural Solid Fuels, "Introduces: ISO 587:1997 [IDT]", ICS 73.040 and 75.160.10, without the fields "Replaces" and "Replaced by". PKN search, term "ISO 587" (08.10.2026): among the first 100 items only this standard has the number 587. evs.ee catalogue: ISO 587:2020 has been in force since 05.08.2020 and replaced ISO 587:1997. The Polish standard therefore corresponds to the ISO edition from before 2020; we do not know how the 2020 edition differs from that of 1997 — apart from the title, which says "Coal and coke" instead of "Solid mineral fuels".

HOW MANY LABORATORIES AND IN WHAT FORM (copy of the accreditation scope database and current PCA documents, read on 08.10.2026). Number 587 appears in 20 records at 12 laboratories; in the current PCA documents (issues from 29.11.2024 to 22.09.2026) — in 18 entries at the same laboratories (at AB 313 each entry is written in Polish and in English); none of them is suspended. The difference comes from AB 550: in the database copy it has 3 records (also solid recovered fuel and waste), and in the current PCA document (issue 33 of 22.09.2026) — one row, for hard coal and brown coal, coke and processed solid fuels. Notations: "PN-ISO 587:2000" — AB 005, AB 103, AB 869, AB 300 (at the same laboratory also "PN ISO 587:2000" and "PN ISO-587:2000 pkt. 7.2.1"), AB 313 (with procedures IPPS-24 version 02 of 30.05.2022 and IPPS-27 version 01 of 18.02.2026); with clause 7.2.1 — AB 079, AB 550, AB 687 and AB 981; with clause 7.2.2 — AB 1089; "PN-ISO 587 p. 7.2.3." — AB 054; "PN-ISO 587:2000 z wyłączeniem pkt. 7.2.2; 7.2.3" (excluding clauses 7.2.2; 7.2.3) — AB 1913. The PKN card lists three ways of determination (Volhard, Mohr, potentiometry with an ion-selective electrode), but does not give clause numbers; the only link between a clause and a technique in the scopes is AB 054: "p. 7.2.3" and "potentiometric titration method". "Laboratories" tab: "PN-ISO 587" shows all 12 laboratories; the term "ISO 587" shows none.

WHAT THE LABORATORIES TEST (PCA documents). Quantity: chlorine content; technique — titrimetric (most of them), potentiometric titration (AB 054, AB 313), "Eschka method" (AB 103). Subject: hard coal and coke; AB 103 and AB 550 — also brown coal, semi-coke and processed solid fuels; AB 313 — also petroleum coke (IPPS-27); AB 869 — combustible waste (alternative fuel) with the code 19 12 10; AB 1913 — in three separate entries hard coal and coke (0.02–1.00 %), solid recovered fuel (0.02–5.00 %) and solid biomass (0.02–0.50 %). Ranges in %: from 0.003 (AB 313: 0.003–0.740 coal, 0.003–0.163 coke, 0.006–0.205 petroleum coke) to 5.00 (AB 1913, recovered fuel); the others: 0.005–1.00 (AB 687), 0.01–1.00 (AB 1089), 0.01–1.0 (AB 550), 0.02–1.00 (AB 300, clause 7.2.1), 0.03–0.24 and 0.04–0.15 (AB 300), 0.03–0.50 (AB 079), 0.03–1.50 (AB 103), 0.04–0.65 (AB 981), 0.050–1.50 (AB 054), 0.07–2.00 (AB 005), 0.10–2.00 (AB 869).

WHERE A SEEMINGLY CORRECT RESULT IS EASY TO GET. First — a subject outside the standard: the scope covers hard coal, brown coal and coke; solid recovered fuels (AB 869, AB 1913) and biomass (AB 1913) are outside it — for solid recovered fuels there is PN-EN 15408, and for solid biofuels PN-EN ISO 16994 (both described in separate entries of this database), so a result according to PN-ISO 587 for such a sample is a result obtained by a method outside the scope of the standard. Second — which final determination: the standard has three ways of determining chlorine after combustion; the report should state which one was used, because the scopes of the laboratories indicate different clauses (7.2.1, 7.2.2, 7.2.3) or none. Third — the edition: PN-ISO 587:2000 is ISO 587:1997, and ISO is in force today in the 2020 edition; a laboratory and a client citing "ISO 587" without a year are referring to a different document than the Polish standard. Fourth — searching: two notations at AB 300 ("PN ISO 587", "PN ISO-587") do not begin with "PN-ISO 587", and only the third one is visible in the tab.

WHAT WE DO NOT GIVE. We did not have the text of the standard — we do not give the composition or the amount of Eschka mixture, the temperature, time and vessels of combustion, the method of extraction, the titration reagents, the electrode, the formulae, the limits of quantification or the precision; we do not assign the Volhard and Mohr methods to clauses 7.2.1 and 7.2.2.

Method principle

The fuel sample is burned mixed with Eschka mixture, and the chlorine bound in the sinter is determined in one of the three ways described in the standard: the Volhard method, the Mohr method or potentiometric titration with an ion-selective electrode (PKN card). Scope: hard coal, brown coal, coke. WE DO NOT GIVE the parameters of combustion and of the determinations — we did not have the text of the standard.

Applications

• Hard coal, brown coal and coke — chlorine content; in the current accreditation scopes of 12 laboratories
• Petroleum coke (AB 313, with procedure IPPS-27) and processed solid fuels (AB 103, AB 550) — according to the scopes of the laboratories
• Fuels from waste (AB 869, AB 1913) and biomass (AB 1913) — outside the scope of the standard; for them PN-EN 15408 and PN-EN ISO 16994

Key parameters

Standard

Standard number

PN-ISO 587:2000 (wersja polska; wprowadza ISO 587:1997 [IDT])

Title (PL)

Paliwa stałe — Oznaczanie zawartości chloru z zastosowaniem mieszaniny Eschki

Title (EN)

Solid mineral fuels — Determination of chlorine using Eschka mixture (title of ISO 587:1997; 2020 edition: Coal and coke — Determination of chlorine using Eschka mixture)

Step-by-step procedure

1. Sample

   Preparation of the test sample according to the standard (PKN card); WE DO NOT GIVE details.

2. Combustion

   Combustion of the sample with Eschka mixture (PKN card); WE DO NOT GIVE the temperature and time.

3. Determination

   Determination of chlorine by the Volhard method, the Mohr method or potentiometric titration with an ion-selective electrode; state in the report the way used.

4. Result

   Chlorine content in percent; WE DO NOT GIVE the formula. PN-ISO 587:2000 current (status of PKN cards as of 08.10.2026).

Required equipment and apparatus

Reagents, media and consumables

Health and safety (OHS)

• Work with a furnace and hot crucibles — gloves, tongs, face shield
• TECHNICAL NOTE: the standard covers hard coal, brown coal and coke — not solid recovered fuels or biomass (for them PN-EN 15408 and PN-EN ISO 16994)

Frequently asked questions