Zeolite Answer

Natural Zeolites

Natural zeolites were formed by the chemical reaction of volcanic ash and alkaline salt water. This chemical reaction gives natural zeolites an open three-dimensional honeycomb and porous structure. The mined zeolite ore is dried, crushed, and screened to meet USGA particle size specifications. Different natural zeolite deposits can have quite different chemical and physical characteristics. A high quality natural zeolite has a high CEC, low clay, low sodium, and high potassium.

A portion of the potassium in the natural zeolite lattice is available to the plant – more on that in a later note. A & L Laboratories determined the soluble potash by the AOAC ammonium oxalate method. The State of Florida allows ZEO to claim EcoSand as a source for potash. The infiltration rate, pore space, and water holding capacity are similar for the various zeolite and calcined clay amendments. Tifton Physical Soil Testing Laboratory determined the properties of the sand and the mixes.

On a custom basis, EcoSand can be loaded with the nutrients that the customer specifies. The zeolite can be loaded with soluble nitrogen; thus, the nitrogen will be slowly cation exchanged into the soil.

Calcined Clays

Calcined clays are produced by heating montmorillonite clays at high enough temperatures to drive out most of the water. This heating converts the clay to a hard porous material. Calcined clays with higher water content usually have higher CEC’s. The three producers of the commercially used calcined clays are located in the northern Mississippi area.

Compared to natural zeolites, the commercial calcined clays have lower CEC’s.

Cation Exchange Capacity

The standard soil laboratory cation exchange capacity test gives a good indication of the CEC of one amendment versus another. The test’s short exchange time (30 to 60 minutes) causes the natural zeolites CEC results to be lower than actual.

For more accurate zeolite CEC’s, the extraction part of the test should be allowed to continue overnight. The CEC results of the calcined clays are not affected by this short exchange time. There can be large differences in results due to lab methods and techniques.

Zeo, Inc.

Related posts:

1. Zeolite Mineral History & Properties