BS ISO 20978:2020
Liming material. Determination of neutralizing value. Titrimetric methods
| Standard number: | BS ISO 20978:2020 |
| Pages: | 24 |
| Released: | 2020-05-18 |
| ISBN: | 978 0 580 92740 9 |
| Status: | Standard |
BS ISO 20978:2020
This standard BS ISO 20978:2020 Liming material. Determination of neutralizing value. Titrimetric methods is classified in these ICS categories:
- 65.080 Fertilizers
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.
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.
The methods described in ISO 6598 and ISO 7497 can be used for the determination of P 2O 5 content. Further information on P analyses is given in References [ 5] and [ 6].
Carbonate consumes H + and removes acidity in solution with subsequent dissociation to H 2O and CO 2. 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.