Because of its high moisture content, the sample becomes kneaded during grinding and the output of small ground fragments use to be quite low. The moisture content also causes a sticking of sample at the lower end of the crushing jaws, for this, a couple of grams still remains inside of the grinding chamber after a total grinding time of 40 minutes.
By using the Jaw Crusher PULVERISETTE 1 Model II with its wider grinding chamber, we are guessing that it might take about 25-30 minutes to grinding the complete sample of 2 kg.
Several other kinds of clay samples have shown, that dry material is way faster to grind. We recommend a pre drying of sample before grinding with a jaw crusher.