ISO/TC 33/WG 17 - Chemical analysis

This document describes methods for the determination of mineralogical phases often present as additives or reaction products in carbon containing or graphitic refractory products by X-ray Diffraction (XRD) using a Bragg-Brentano diffractometer. It includes details of sample preparation and general principles for qualitative and quantitative analysis of mineralogical phase composition. Quantitative determination of α-Si3N4, β-Si3N4, AlN, aluminium metal, Al4C3, silicon metal, boron carbide and BN are described. The problems encountered with some determinations are highlighted. Additional reduced species present in some refractories could include Al2O3⋅AlN solid solutions (so called Alons), Si3N4⋅SiO2 solid solutions and Si3N4⋅Al2O3 solid solutions (Sialons). The presence of some of these solid solution components will cause problems with both identification and quantification as they are not well-defined structures. NOTE For rationalisation of nitrogen containing phases, the total nitrogen content, analysed in accordance with EN 12698-1 is used.

This document specifies requirements for the preparation of fused beads for the chemical analysis of silicon carbide containing samples using X-ray fluorescence (XRF). The test methods described in this document are for silicon carbide and silicon carbide materials; however, the principles described can be applied to other reduced materials such as boron carbide, boron nitride, ferroalloys, sialons and silicon nitride using the modifications given in Annex A. Fused cast beads of the samples prepared in accordance with this document are analysed in accordance with ISO 12677.

ISO 22016:2015 specifies methods for the wet chemical analysis of refractory products and their raw materials with below 5 % (mass percentage) sulfur.

This part of ISO 14720 defines a method for the determination of sulfur in powdered and granular non-oxidic ceramic raw materials and materials, which are completely oxidized at a higher temperature in an oxygen atmosphere, e.g. carbon and graphite materials. For materials which are not completely oxidizable under these conditions, it is possible to determine sulfur that can be released under these conditions, e.g. the adherent sulfur. This part of ISO 14720 is applicable for materials with mass fractions of sulfur ≤ 10 % and mass fractions of ash For the lower detection limit of this method, a mass fraction of sulfur of 0,5 mg/kg in the case of inductively coupled plasma optical emission spectrometry (ICP/OES) and 5 mg/kg in the case of ion chromatography (IC) has to be considered as a recommended value.

ISO 14720-1:2013 defines a method for the determination of sulfur in powdered and granular non-oxidic ceramic raw materials and materials, such as silicon carbides, silicon nitrides, graphites, carbon blacks, cokes, carbon powders. If proved by the recovery rate, this method can also be applied for other non-metallic powdered and granular materials, e.g. silicon dioxide. ISO 14720-1:2013 is applicable for materials with mass fractions of sulfur from 0,005 % to 2 %. ISO 14720-1:2013 can also be applied for materials with higher mass fractions of sulfur after verification of the particular case.

ISO 14719:2011 specifies a spectral photometric method with 1,10-phenanthroline for the quantitative determination of Fe2+ and Fe3+ in oxidic raw and basic materials for ceramics, glass and glazes, e.g. feldspar, kaolinites, clay, limestone, quartz refractory materials. ISO 14719:2011 could be extended to other aluminosilicate materials, providing that uncertainty data is produced to support it. However, there might be problems in the decomposition of high-purity alumina and chrome ore samples. The method is not suitable for reduced materials, such as silicon carbide, graphite-magnesia, etc.

ISO 12677:2011 specifies a method for the chemical analysis of refractory and technical ceramic raw materials, intermediates and products, by means of the X-ray fluorescence (XRF) fused cast-bead method. Typical materials that can be analysed by ISO 12677:2011 are given in Clause 3. ISO 12677:2011 is not applicable to non-oxide materials, such as silicon carbides or nitrides, etc. The method is applicable to a wide range of materials containing a wide range of elements.

ISO 21068-3:2008 specifies methods for the determination of total nitrogen and nitrogen calculated as silicon nitride, total oxygen, and free metallic and oxidic components in silicon carbide raw materials and refractory products. It applies only to silicon carbide materials that are not bonded with nitrogen. Nitride-bonded silicon carbide refractories are covered in EN 12698-1.

ISO 21068-1:2008 gives definitions and specifies techniques for the preparation of samples for the chemical analysis of silicon-carbide-containing raw materials and refractory products.

ISO 21068-2:2008 specifies analytical techniques for the determination of change in mass by thermal treatment at specified temperatures, and methods for the determination of the total carbon content, free carbon, silicon carbide, silicon, total silica and free silica content of silicon-carbide-containing raw materials and refractory products.

ISO 21079-1:2008 specifies methods for the chemical analysis of AZS (alumina, zirconia, and silica) refractory products (containing 5 % to 45 % of ZrO2) and raw materials, using traditional ("wet") methods, inductively coupled plasma atomic emission (ICP-AE) spectrometry and flame atomic absorption (FAA) spectrometry. It covers apparatus, reagents and dissolution methods. ISO 21079-1:2008 is not applicable to MgO-based refractories. ISO 21079-1:2008 gives alternatives to the X-ray fluorescence (XRF) method given in ISO 12677.

ISO 21079-2:2008 specifies methods for the chemical analysis of AZS (alumina, zirconia, and silica) refractory products (containing 5 % to 45 % of ZrO2) and raw materials, using traditional ("wet") methods. ISO 21079-2:2008 is not applicable to MgO-based refractories. ISO 21079-2:2008 gives alternatives to the X-ray fluorescence (XRF) method given in ISO 12677.

ISO 21079-3:2008 specifies flame atomic absorption spectrophotometry (FAAS) and inductively coupled plasma emission spectrometry (ICP-AES) methods for the analysis of AZS (alumina, zirconia, and silica) refractory products (containing 5 % to 45 % of ZrO2) and raw materials. ISO 21079-3:2008 is not applicable to MgO-based refractories. ISO 21079-3:2008 gives alternatives to the X-ray fluorescence (XRF) method given in ISO 12677.

ISO 21078-1:2008 specifies methods of determining boron(III) oxide in refractory products and raw materials, in mass fractions of 0,01 % or greater. It is applicable to the determination of total boron(111) oxide in oxidic materials for ceramics, glass and glazes.

ISO 12677-3:2007 specifies inductively coupled plasma/atomic emission (ICP/AE) spectrometry and flame atomic absorption (FAA) spectrometry methods for the chemical analysis of aluminosilicate refractory products and raw materials. The methods are applicable to the determination of the following: silicon(IV) oxide (SiO2) aluminium oxide (Al2O3) iron(III) oxide (total iron oxide calculated as Fe2O3) titanium(IV) oxide (TiO2) manganese(II) oxide (MnO) calcium oxide (CaO) magnesium oxide (MgO) sodium oxide (Na2O) potassium oxide (K2O) chromium(III) oxide (Cr2O3) zirconium oxide (ZrO2) phosphorous(V) oxide (P2O5) This part of ISO 12677 gives alternatives to the X-ray flluorescence (XRF) method given in ISO 12677:2003

ISO 12677-2:2007 specifies traditional ("wet") methods for the chemical analysis of aluminosilicate refractory products and raw materials. The methods are applicable to the determination of the following: silicon(IV) oxide (SiO2) aluminium oxide (Al2O3) iron(III) oxide (total iron oxide calculated as Fe2O3) titanium(IV) oxide (TiO2) manganese(II) oxide (MnO) calcium oxide (CaO) magnesium oxide (MgO) sodium oxide (Na2O) potassium oxide (K2O) chromium(III) oxide (Cr2O3) zirconium oxide (ZrO2) phosphorous(V) oxide (P2O5) This part of ISO 12677 gives alternatives to the X-ray fluorescence (XRF) method given in ISO 12677:2003.

ISO 21587-1:2007 specifies reagents, dissolution and gravimetric silica analysis for the chemical analysis of aluminosilicate refractory products and raw materials. ISO 21587-1:2007 gives alternatives to the X-ray fluorescence (XRF) method given in ISO 12677:2003.

ISO 21078-2:2006 specifies procedures of chemical analysis for the determination of boron(III) oxide used as a binder component added to aluminosilicate refractories, using an acid extraction method. It is applicable for refractories containing less than 1 % (mass fraction) of boron(III) oxide.

ISO 12677:2003 specifies a method for chemical analysis of refractory products and materials, and technical ceramics composed of oxides, including the determination of oxide at levels between 0,01 % and 99 % by means of the XRF fused cast bead method.