ISO 20978:2020
2020-05
Abstract
This document specifies two methods for the determination of the neutralizing value (NV) of liming materials.
Method A is applicable to all liming materials except silicate liming materials.
NOTE 1 Examples of hard liming materials are limestone and dolomite. Examples of soft liming materials are chalk, marl and burnt lime.
Method B is applicable to all liming materials.
Neither method correctly takes into account the potential neutralizing value of material containing more than 3 % P2O5. For a more accurate agronomic assessment of products containing more than 3 % P2O5, EN 14984[8] is used to determine the liming efficiency.
NOTE 2 The methods described in ISO 6598 and ISO 7497 can be used for the determination of P2O5 content. Further information on P analyses is given in References [5] and [6].
NOTE 3 Carbonate consumes H+ and removes acidity in solution with subsequent dissociation to H2O and CO2. Forms of orthophosphate can consume H+ but are not dissociated to molecular forms that remove acidity. The acidity is back titrated with alkali causing an underestimation of NV.
General information
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Status: PublishedPublication date: 2020-05Stage: International Standard published [60.60]
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Edition: 1Number of pages: 15
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Technical Committee :ISO/TC 134ICS :65.080
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