ISO DIS 20978

Description / Abstract: This ISO Standard 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.

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, determine the liming efficiency according to EN 14984 [8].

NOTE The methods described in ISO 6598 [1] and ISO 7497 [2] can be used for the determination of P₂O₅ content. Further information on P analyses is given in bibliography [3] [4].

NOTE 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.