Zeolites belong to a family of naturally occurring volcanic minerals with unique physical and chemical characteristics. There are over forty-eight varieties of natural zeolite minerals with similar structures and molecular makeup, each with its own particular attributes – some subtle and some more obvious. learn more
“Natural zeolites (i.e., those found in volcanogenic sedimentary rocks) have been and are being used as building stone, as lightweight aggregate and pozzolans in cements and concretes, as filler in paper, in the take-up of Cs and Sr from nuclear waste and fallout, as soil amendments in agronomy and horticulture, in the removal of ammonia from municipal, industrial, and agricultural waste and drinking waters, as energy exchangers in solar refrigerators, as dietary supplements in animal diets, as consumer deodorizers, in pet litters, in taking up ammonia from animal manures, and as ammonia filters in kidney-dialysis units.
From their use in construction during Roman times, to their role as hydroponic (zeoponic) substrate for growing plants on space missions, to their recent success in the healing of cuts and wounds, natural zeolites are now considered to be full-fledged mineral commodities, the use of which promise to expand even more in the future.”
(From a paper was presented at National Academy of Sciences colloquium "Geology, Mineralogy, and Human Welfare," held November 8-9, 1998 at the Arnold and Mabel Beckman Center in Irvine, CA.Colloquium Paper “La roca magica: Uses of natural zeolites in agriculture and industry” Frederick A. Mumpton )
Natural Zeolite Structure
Generally speaking, natural zeolites are hydrated aluminosilicates. They consist of an open, three-dimensional cage-like structure and a vast network of open channels extending throughout. Loosely bound, positively charged atoms called cations, are attached at the junctures of the negatively charged aluminosilicate lattice structure. The aluminosilicate framework provides exceptional strength and stability to the lattice structure.
The channels, typically 0.3 to 0.7 nanometers in diameter (3 to 7 angstroms, slightly larger than a water molecule), selectively screen molecules according to size and exchangeable cations. Molecules too large to pass through the entry channel are excluded, thus giving rise to the term “molecular sieve”.
The molecular structure, surface area, surface charge density, and cation exchange capacity (CEC) of each particular zeolite will determine its loading, shrinking, swelling and stability under various conditions.
Zeolites have a rigid, three-dimensional crystalline structure (similar to honeycomb) consisting of a network of interconnected tunnels and cages. Zeolites in general have high specific surface areas and their rigid framework limits shrinking and swelling.
Perhaps the most commercially valuable and dynamic property of zeolite is its cation exchange capacity (CEC). Cation exchange occurs when two or more positively charged compounds or elements exchange places on a negatively charged host. The most common exchangeable cations found in natural zeolite molecules are sodium, calcium, potassium, and magnesium, many of which are desirable in numerous biological and industrial processes.
The ability to release beneficial elements while capturing and binding other, often less desirable, materials makes zeolite an ideal media for the selective adsorbtion of certain elements and compounds from soil, water and air.
A classic example of cation exchange is the removal of ammonia from water and air. When a molecule of ammonia (NH3) is hydrated, the reaction produces ammonium (NH4+), which is readily exchanged for all or part of the calcium, potassium and magnesium cations contained in St. Cloud Zeolite and adsorbed on to its stable aluminosilicate lattice.
St. Cloud Zeolite - An Innovative Solution
How does cation exchange and the ability to effectively bind ammonia benefit you? One good example is when St. Cloud Zeolite is mixed into an animal’s feed.
St. Cloud Zeolite can exchange calcium for the ammonia naturally produced by the animal’s digestive process. St. Cloud Zeolite adsorbs the ammonia, which then passes with the zeolite through the animal’s lower digestive tract without reacting further. It not only reduces the amount of ammonia being released as a harmful gas, but also retains it in the manure as added nitrogen, thereby increasing the nutrient value of the manure for use as fertilizer.
Ammonia has the highest cation exchange capacity with clinoptilolite, which is the primary form of zeolite found at St. Cloud. St. Cloud Zeolite is widely accepted for use in the agricultural industry as both a soil amendment and as a feed additive.
Natural vs. Synthetic Zeolites
In addition to natural zeolites, synthetic zeolites are also in widespread use in a number of commercial and industrial applications today. Unlike naturally occurring zeolites, synthetic zeolites are manufactured in energy-intensive chemical processes and are significantly more expensive than natural zeolite.
Synthetic zeolites are also designed to meet ion-specific exchange requirements in highly discriminating applications. The synthetic zeolite lattice is generally manufactured with a silica to alumina ratio of 1 to 1 as compared to the 5 to 1 ratio of natural St. Cloud Zeolite. The enhanced silica to alumina ratio of the St. Cloud Zeolite serves to stabilize and strengthen the lattice, making it more durable particularly in mildly acidic environments and more versatile across a broad array of applications.
Industries & Applications
Industries that have implemented innovative approaches through the utilization of zeolite include both plant and animal agriculture, manufacturing, food preparation and preservation, water treatment and purification, turf and soil amendments, industrial flow agents, household uses and many others.
Take a good look at what St. Cloud Zeolite can do to lower your costs and increase your efficiency and profitability, while providing numerous other benefits. St. Cloud is the partner you need to help you get started.