Investigation of gypsum dissolution under saturated and unsaturated water conditions

Batch and column experiments were carried out to study the dissolution of gypsum by water under saturated and unsaturated conditions. The experimental results were verified by calculations. Comparing the dissolution in batch and column experiments, which were performed with a water flow velocity of 0.015 cm/h, one has to conclude that under unsaturated conditions only the very small portion of 2.2% of the grain surface is chemically reactive. Experiment and calculation show that the gypsum release in the column is mainly determined by the flow velocity.