Has anyone ever used this as amendment for the soil? It should be rich in Silica and Aluminium (I keep reading occasional Axel's reports about needs in Aluminium of madagasian palms), it has a great cation exchange capability and can prevent a to fast potassium leaching, absorbing as sponge the potassium itself and letting then palm roots tap it slowly. Besides it has the tendency to neutralize alkaline and acid soils plus that it absorbs from soil many toxins (so it cleans soil even from herbicides and other impurities to be found in irrigation water?).

The Aluminum and Silica won't be available to the plant, but the Zeolite itself is good for the soil because of the porosity and CEC. For these purposes though, charcoal is also very good, but likely much cheaper. Unless you have a source of very cheap/free Zeolite, I would just get powdered charcoal.