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This document specifies the method for the determination of the water-soluble chromium (VI) content of cement.
A reference method is described consisting of two stages, an extraction procedure and an analysis of the filtered extract. Guidance on other extraction procedures, suitable for screening tests, for factory production control or other purposes, is given but in case of dispute or failure to comply with a regulatory limit only the reference method is used. The reference method has alternatives whereby the filtered extract can be subjected to an oxidation step or not. The criteria by which the appropriate procedure is selected are set down. Other instrumental procedures can be used for the analysis of the filtered extract provided they are calibrated against the analysis of the filtered extract using the reference procedure. In the case of a dispute, only the reference method is used.
This document specifies, for the determination of water-soluble chromium (VI) in the filtered extract, the reference methods (colorimetric determination by diphenylcarbazide in acidic conditions) and another method for the determination of total water-soluble chromium (by inductively coupled plasma optical emission spectroscopy, ICP-OES).
The ICP-OES determines the total chromium content independently of the chemical species, i.e. whether it is present as chromium (III) or chromium (VI), for example. Experience has demonstrated that soluble chromium (VI) is predominantly present during the processing phase, such that, in most cases, the determination of total water-soluble chromium effectively reflects the chromium (VI) content. The water-soluble chromium (VI) content of cement can therefore be assessed conservatively using the method based on ICP-OES described in this document.
In the case of a dispute, only the reference methods are used. This document specifies a method that applies to cements.
NOTE 1 Annex A provides guidance on the possible application of this document to the determination of the water-soluble chromium (VI) content of cement-containing preparations.
NOTE 2 Annexes B and C provide information on other test procedures based on paste extraction and thus depart from the performance of cement in its normal conditions of use. They can be carried out with or without the oxidation process. It is important that users are aware that results using these methods might be significantly different to those obtained by the reference method. In the case of dispute or failure to comply with the regulatory limit, only the reference method is used.
NOTE 3 Annex D provides guidance on a method for determination of the excess reducing agent content of cement as used in the factory internal control system of some countries. It is important that manufacturers using such an internal control method assure themselves of the relevance of results in comparison with testing by the reference method.
Reģistrācijas numurs (WIID)
80960
Darbības sfēra
This document specifies the method for the determination of the water-soluble chromium (VI) content of cement.
A reference method is described consisting of two stages, an extraction procedure and an analysis of the filtered extract. Guidance on other extraction procedures, suitable for screening tests, for factory production control or other purposes, is given but in case of dispute or failure to comply with a regulatory limit only the reference method is used. The reference method has alternatives whereby the filtered extract can be subjected to an oxidation step or not. The criteria by which the appropriate procedure is selected are set down. Other instrumental procedures can be used for the analysis of the filtered extract provided they are calibrated against the analysis of the filtered extract using the reference procedure. In the case of a dispute, only the reference method is used.
This document specifies, for the determination of water-soluble chromium (VI) in the filtered extract, the reference methods (colorimetric determination by diphenylcarbazide in acidic conditions) and another method for the determination of total water-soluble chromium (by inductively coupled plasma optical emission spectroscopy, ICP-OES).
The ICP-OES determines the total chromium content independently of the chemical species, i.e. whether it is present as chromium (III) or chromium (VI), for example. Experience has demonstrated that soluble chromium (VI) is predominantly present during the processing phase, such that, in most cases, the determination of total water-soluble chromium effectively reflects the chromium (VI) content. The water-soluble chromium (VI) content of cement can therefore be assessed conservatively using the method based on ICP-OES described in this document.
In the case of a dispute, only the reference methods are used. This document specifies a method that applies to cements.
NOTE 1 Annex A provides guidance on the possible application of this document to the determination of the water-soluble chromium (VI) content of cement-containing preparations.
NOTE 2 Annexes B and C provide information on other test procedures based on paste extraction and thus depart from the performance of cement in its normal conditions of use. They can be carried out with or without the oxidation process. It is important that users are aware that results using these methods might be significantly different to those obtained by the reference method. In the case of dispute or failure to comply with the regulatory limit, only the reference method is used.
NOTE 3 Annex D provides guidance on a method for determination of the excess reducing agent content of cement as used in the factory internal control system of some countries. It is important that manufacturers using such an internal control method assure themselves of the relevance of results in comparison with testing by the reference method.
