ZEOLITE

The identification of Zeolite as a mineral dates to 1756, when Freiherr Axel Fredrick Cronstedt, a Swedish mineralogist, began collecting some "well-formed crystals" from a Copper mine in Sweden . He named the minerals "Zeolite" from the Greek words meaning "boiling stones", that is, because they could "froth" when heated to high temperatures (at about 200  oC ).

      Zeolites soon became recognized by geologists and mineralogists and have been used in varies application areas because of their attractive physical and chemical properties. The natural sedimentary Zeolites are considered as micro porous adsorbents, ion-exchangers and catalysts, which have various uses in industry, agriculture, and in environmental protection.

        Mineralogy and Crystal Chemistry of Zeolites:

        The general chemical formula for Zeolites is,

        Mx Dy [Alx+2y Sin- (x+2y)O2n].mH2O

        M: Na, K or other monovalent cations

        D: Mg, Ca, Si, Ba and other divalent cations.

     Framework atoms are enclosed by the square brackets. One important chemical parameter of every Zeolite is the fraction of SiO4 tetrahedra, R= Si: (Si+Al). R ranges from 0.5 o 0.87 and remains constant during most cation exchanges, whereas most or all nonframework ions are exchangeable. The number of water molecules indicates the pore volume and usually n/2<M

        This very open framework structure characterized by networks of channels or pores, gives the mineral a very large surface area. For instance, half a kilo of Zeolite powder has about the same surface area as a football field. The structure has a negative charge and with its large surface area has a high cation exchange capacity (CEC).

        The unique structure differ Zeolites from "other" aluminosilicate, due to the following special properties:

Gas absorption: the ability to selectively absorb specific gas molecules,

Water Absorption/Desorption: The ability to reversibly absorb water without any chemical or physical change in the Zeolite matrix,

Ion exchange: The ability to exchange inherent cations for other cations on a basis of ion selectivity.

Benefits of Zeolites

The high CEC makes Zeolite particularly efficient in holding and slow releasing the valuable nutrients to the plants, mainly ammonium nitrogen (NH4+), potassium (K+), magnesium (Mg+), calcium (Ca+) and other elements,

Improves the cation exchange capacity of soil resulting in less fertilizer requirement,

Promotes better plant growth by improving the value of fertilizer. Helps preventing the plant from burning, that can be caused by over use of fertilizer, by trapping and slowly releasing valuable nutrients when the plant needs them,

The water retention capability of Zeolites allows less irrigation,

Improves water quality and filtration in aquaculture,

Increase the biological activity of sewage treatment and improves the value of resultant sludge,

Reduces nutrient and fertilizer loss through heavy rains, leaching and irrigation, resulting in less environmental damage through water runoff,

This retained valuable nitrogen improves the quality of the resulting manures and sludge making them worthwhile in fertilizer,

Natural Zeolites make an excellent soil amendment, and are environmentally friendly for landfill dump sites (with the exception of Zeolite that has been used as a molecular sieve or filter medium for the removal of radioactive waste or the removal of heavy chemical toxins deemed hazardous by government regulations),

Zeolites are used to reduce offensive odours, especially ammonia from sewage, animal manure and wastewater situations,

Zeolites can be used in the removal of heavy metals from mining and metallurgical wastewaters. 

CLINOPTILOLITE

General Information

Clinoptilolite: Hydrated Sodium Potassium Calcium Aluminium Silicate.

General formula is;

(Na,K,Ca)2-3 Al3(Al,Si)2Si13 O36.12H2O

Class: Silicates

Group: Zeolites

Geometrical shape of Clinoptilolite

It is used as a chemical filter, chemical absorber and purifier and as mineral specimens.

Clinoptilolite is one of the useful natural Zeolites. It is used in many applications such as a chemical sieve, a gas absorber, a feed additive, a food additive, a fertilizer additive, a soil amendment, soil container, control agent and as a water filter for municipal and residential drinking water and aquariums. New technological improvements on the applications are being continued in many countries. Clinoptilolite is well conformed to these applications due to its large amount of pore space, high resistance to extreme temperatures and chemically neutral basic structure. Clinoptilolite has being used as an additive to animal feed. It absorbs toxins and microscopic parasites in the feed that are created by soil, and enhances food absorption in these animals; cows pigs, horses, chickens, etc. Clinoptilolite can easily absorb ammonia and other toxic gases from air and water, hence, can be used as a filter for cleanliness and for odour removal.

Scanning electron micrographs of tuff from Gördes, Manisa are illustrated below. X-ray powder diffraction studies indicate that this is almost pure Clinoptilolite.

In general, the monoclinic habit of Clinoptilolite is easily recognized in the scanning electron microscope.

Scanning electron micrograph of clinoptilolite tuff from Gördes, Manisa (The sample is taken from open pit mine of Enli Mining Corporation). (Crystalline structure of clinoptilolite tuff).

Some Physical Characteristics of Clinoptilolite

Colour:  white, colourless, pink, yellow, reddish, pale green and pale brown

Luster:  vitreous on the pinacoid face and on cleavage surfaces

Transparency: crystals vary from transparent to translucent

Crystal System: monoclinic, 2/m

Crystal Habits: include blocky or tabular crystals with good monoclinic crystal form more tabular and proportioned than heulandites. Also commonly found in acicular (needle thin) crystal sprays.

Cleavage:  perfect in one direction, parallel to the prominent pinacoid face.

Fracture:  uneven

Hardness: 3-4 may be softer on cleavage surfaces

Specific Gravity:  approximately 2.2 (very light)

Streak: white

Other Characteristics: can absorb a significant amount of water after drying and will retain its structure even if heated to almost the temperature of melted glass. 

Usage of Clinoptilolite over the world

Ø                   Pollution-Control:

Radioactive-waste disposal

Sewage-effluent treatment

Agricultural-wastewater treatment

Stack-gas clean up

Oil-spill clean up

Oxygen production  

Ø                   Energy-Conservation

Coal gasification

Natural gas purification

Solar energy use

Ø                   Agricultural Significance

Fertilizer uses

Herbicide and pesticide carriers

Animal nutrition

Animal-waste treatment

Aqua cultural applications

Ø                   Mining and Metallurgy

Exploration aids

Hydrometallurgical uses

Ø                   Construction uses

Ø                   Medical applications

Ø                 Miscellaneous

PRODUCTS

NATMIN...................................Animal feed additive, Covers EU feed lows(Contents minimum 85 % Clinoptilolite)

AGROCLINO...........................Fertilizer additive and soil amendment ,High C.E.C., water adsorption capacity,

CLINO CIM.............................Fertilizer additive and soil amendment, especially for grasses, golf courses, horticultural application High C.E.C., water adsorption capacity,

ZETA........................................Animal litter High C.E.C., ammonium adsorbent, odour and moisture removing,

FILTER CLINO....................Drinking and waste water treatment, High C.E.C., ammonium adsorbent, and heavy metal adsorbent, particle size is optional

CLINOTOPLILOLITE.......For current and other application, prepared for demands, special material