Milling

The soil sample needs to be very fine before it can be measured. Therefore we use the Fritsch ball
mill that grinds the soil to a particle size smaller than 0.1 mm and makes the soil fully homogeneous.

1. Start Fritsch mill and turn on the control panel by pulling it towards you.
2. Press “open” and take the first pot out. Open the pot: inside there should be 10 balls and a silicone ring.

3. Pour the vial sample in the pot and close it. The black handles of the lid should fit perfectly in the pot. Lower the pot in Fritsch and push the red button, the pot will fall in place. Then push the black knob on the lid to push the pot further down. Lower the black hooks to keep the pot in place during the milling.

4. Press 2, the Frisch will turn and place the second pot in front of you.

5. Take the second pot out, fill it with the next sample, close it and put in back in.

Menu settings for the Fritsch ball mill should be as follows:

Speed: 500 rpm, Timer: 180 sec, Pause: 00 sec, Cycles: 01/01, Reverse: Off

Always mill 2 SAMPLES at the same time. Always mill with 10 BALLS per pot. Doing otherwise will DAMAGE the Fritsch mill.

6. Press Start and mill for 3 minutes

7. After 3 minutes, the mill stops automatically, press Open and take the first pot out. Use the funnel and the sieve to pour the sample back into the initial vial (use the scraper for the remains of the sample).

8. Repeat the procedure with the second pot.

Cleaning:

Always clean the pots before milling a new sample. Soil from a previous sample can decrease the accuracy of the soil analysis. Clean balls, scraper, funnel and sieve with water and dry them with a paper towel.

Always leave the Fritsch clean at the end of the day. Use cleaning sand if available to clean the pot: pour 30ml of the cleaning sand in the pots, close them, place them in the Fritsch following the previous procedure, and mill both pots full of sand for 3 minutes. Then clean both pots with dry paper towels and throw the used sand
away.