cen:proj:80064

prCEN/TS 17685-3 "Earthworks — Chemical tests — Part 3: Determination of carbonate content in soils" cen:proj:80064

Scope

The aim of this standard is to describe a test to find the carbonate content of a soil sample using a Bernard or a Dietrich-Frulling calcimeter.
This method is based on the decomposition of carbonates by the action of hydrochloric acid, and measure of gaseous carbon dioxide CO2 generated, according to the following reaction, in which M is the cation that accompanies carbonate, usually Ca 2+ or Mg2+: 𝑀𝐶𝑂3+ 2𝐻𝐶𝑙 →𝑀𝐶𝑙2+𝐶𝑂2 (𝑔)+𝐻2𝑂
Ambient pressure and temperature have an influence on the volume of CO2 gas produced in the reaction, so it is necessary a calibration test of the calcimeter with a known amount of pure calcium carbonate (CaCO3).
In this method is assumed that all carbonates present in the sample are calcium carbonates. Therefore, if a soil sample contains non-calcium carbonates, the result obtained with this standard may differ from the total carbonate content of the sample.