ISO 5976:2025

International
Standard
ISO 5976
First edition
Rare earth — Determination of loss
2025-10
on ignition in rare earth products —
Gravimetric method
Terres rares — Détermination de la perte au feu dans les produits
à base de terres rares — Méthode gravimétrique
Reference number
© ISO 2025
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Published in Switzerland
ii
Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Principle . 2
5 Apparatus . 2
6 Sampling . 2
7 Procedure . 2
7.1 General .2
7.2 Test portion .2
7.3 Preparation of crucible with lid .3
7.4 Determination of the loss on ignition (LOI) .3
7.5 Parallel test .3
8 Calculation and expression of results . 3
8.1 Calculation of loss on ignition (LOI) .3
8.2 Precision . . .4
9 Test report . 5
Annex A (informative) Interlaboratory test results . 6
Bibliography . 8

iii
Foreword
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This document was prepared by Technical Committee ISO/TC 298, Rare earth.
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iv
Introduction
Determination of loss on ignition (LOI) is widely used as a method to detect the content of such substances
as water, carbon dioxide and sulfur dioxide in rare earth oxides, carbonates and oxalates. It is usually a
preliminary step for chemical composition analysis or physical performance inspection of rare earth
analytes. A scientific and standardized LOI testing method minimizes deviation between sample results
across laboratories, improves consistency and comparability of interlaboratory data, reduces potential
trade disputes and facilitates fair trade of rare earth products.
Rare earth oxides can contain one rare earth element or more than one rare earth element (mixed rare-
earth elements). Typical mixed rare earth oxides are praseodymium-neodymium oxide, lanthanum-cerium
oxide, yttrium-europium oxide and lanthanum-cerium-praseodymium-neodymium oxide.
Similar to rare earth oxides, rare earth carbonates and rare earth oxalates can also include individual and
mixed rare earth elements.
This document provides a determination method for LOI for such analytes as rare earth oxides, carbonates
and oxalates and can be used by rare earth producers, consumers, traders as well as other relevant
stakeholders.
v
International Standard ISO 5976:2025(en)
Rare earth — Determination of loss on ignition in rare earth
products — Gravimetric method
WARNING — The use of this document may involve hazardous materials, operations and equipment.
It does not purport to address all of the safety problems associated with its use. It is the responsibility
of the user of this document to establish appropriate health and safety practices and determine the
applicability of regulatory limitations prior to use.
1 Scope
This document specifies a gravimetric method for the determination of the loss on ignition (LOI) in solid
rare earth oxides, carbonates and oxalates.
This document is applicable to the determination of the LOI in the range from 0,10 % to 15,00 % in rare
earth oxides, from 25,00 % to 80,00 % in rare earth carbonates, and from 35,00 % to 75,00 % in rare earth
oxalates.
2 Normative references
The following documents are referred to in the text in such a way that some or all their content constitutes
requirements of this document. For dated references, only the edition cited applies. For undated references,
the latest edition of the referenced document (including any amendments) applies.
ISO 5725-2, Accuracy (trueness and precision) of measurement methods and results — Part 2: Basic method for
the determination of repeatability and reproducibility of a standard measurement method
ISO 22444-1, Rare
...