Carbonate content (%) is calculated as:
| Step | Action | |------|--------| | 1 | Dry the soil sample at 105°C to a constant mass. | | 2 | Crush soil to pass a No. 200 (75 µm) sieve. | | 3 | Weigh a specimen (typically 1–10 g, depending on expected carbonate content). | | 4 | Place specimen into the reaction vessel. | | 5 | Add HCl (without allowing contact until sealed) into a separate chamber or capsule within the vessel. | | 6 | Seal the gas-measuring apparatus. | | 7 | Tip the apparatus to allow acid to contact the soil. | | 8 | Record the maximum gas pressure or volume reading after reaction stabilizes (usually 1–2 minutes). | astm d 4373
| 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 | Carbonate content (%) is calculated as: | Step
[ \textCarbonate (%) = \frac\textCO_2 \text pressure/volume reading\textDry soil mass \times \textCalibration factor ] | | 3 | Weigh a specimen (typically
[ CaCO_3 + 2HCl \rightarrow CaCl_2 + H_2O + CO_2 \uparrow ]