Astm D 4373 //free\\ Guide

Or directly from a pre-established calibration curve using pure CaCO₃.

The method relies on the chemical reaction between carbonates present in the soil and hydrochloric acid (HCl). The reaction produces carbon dioxide (CO₂) gas.

[ CaCO_3 + 2HCl \rightarrow CaCl_2 + H_2O + CO_2 \uparrow ] astm d 4373

1. Title Standard Test Method for Rapid Determination of Carbonate Content of Soils

D4373 – 14 (or current active version: 2021) Or directly from a pre-established calibration curve using

| Sample ID | Dry Mass (g) | CO₂ Reading (mL) | CaCO₃ Equivalent (%) | |-----------|--------------|------------------|------------------------| | S-01 (CL) | 5.00 | 38.5 | 10.2 | | S-02 (GW) | 10.00 | 122.0 | 32.8 |

A calibrated manometric or volumetric device (typically a or similar gas-measuring apparatus) measures the pressure or volume of CO₂ evolved. This measurement is directly proportional to the CaCO₃ content, which is expressed as a percentage of the dry soil mass. [ CaCO_3 + 2HCl \rightarrow CaCl_2 + H_2O

[ \textCarbonate (%) = \frac\textCO_2 \text pressure/volume reading\textDry soil mass \times \textCalibration factor ]