Hot Soxhlet Sample Cleaning and Drying
Prior to any analyses, these samples must be cleaned of the fluids, oil and water present in the sample and to remove the salts. The process involves refluxing solvents in apparatus called “Soxhlets”.
Hot solvents boil in a round bottom flask. The clean solvent vapours rise and are condensed in the condenser. Warm solvent drips down in the sample chamber. The samples are soaked in warm solvents till the chamber is full of solvent when it automatically drains down in the lower round bottom flask. This ensures that the samples are soaked only in clean solvents at any point in time.
Hot solvents like Toluene and Methanol are refluxed in these soxhlets to selectively clean the samples of oil and water and salts.
Sometimes different chemicals are used for prevention of damage to the core.
Once the sample are cleaned, they are dried in either conventional or humidity ovens to be ready for analyses.
Chloroform – Methanol Mix if required can also be used.
Once the samples are cleaned, the samples are dried in a conventional oven. The oven has a maximum temperature of 150 deg C.
Temperature set is usually 110 deg C.
Temperature can be varied if lower boiling point solvents are used.
Special Handling for Samples Containing Sensitive Clays
Sensitive clays can be damaged if subjected to Hot Solvent cleaning and drying in a conventional oven.
Such samples are required to be cleaned in Cool Cleaning Soxhlets and drying in a Humidity Oven.
Difference in porosity measurements after drying with humidity oven and then after drying with conventional oven will determine the porosity lost due to clay.