What Are Zeolites?

Zeolite is a mineral that was first discovered in 1756. Swedish mineralogist Cronstedt found a class of natural aluminosilicate ore that boils when burned, so he named it "zeolit" (Swedish). In Greek it means "lithos" (zeo). Since then, research on zeolites has continued.

In 1932, McBain proposed that "

It will not decompose if used and stored in accordance with the specifications. There are no known dangerous reactions to avoid oxides. Soluble in strong bases. Is a high silica zeolite. It has a unique pore structure, high catalytic activity and thermal stability, and acid resistance.

Zeolite is a general term for zeolite family minerals, which is an aqueous alkali or alkaline earth metal aluminosilicate mineral. More than 40 natural zeolites have been found all over the world, the most common of which are clinoptilolite, mordenite, chabazite, erionite, phillipsite, zeolite, zeolite, fluorite, and alumina. Extensive use has been made of clinoptilolite and mordenite. The zeolite family minerals have different crystal systems. Most of the crystals are fibrous, hairy, columnar, and a few are plate-like or short-column-shaped.

Zeolites have ion exchange properties, adsorption and separation properties, catalytic properties, stability, chemical reactivity, reversible dehydration properties, and electrical conductivity. Zeolites are mainly produced in the fissures or almonds of volcanic rocks and coexist with calcite, pith, and quartz; they are also produced in volcanic clastic sediments and hot spring sediments. ^[4]

There are more than 80 types of zeolites that have been found in nature.

First, clinoptilolite clinoptilolite in the dense structure of the rock is mostly in the form of radial plate aggregate microforms, and in the pore development, it can form plate crystals with intact or partially intact geometry, up to 20mm wide. The thickness is about 5mm, the ends are about 120 degrees, and some are diamond-shaped plates and slats. The EDX spectrum is Si, Al, Na, K, Ca.
Second, the morphology of mordenite SEM is fibrous, with filaments as straight or slightly curved, with a diameter of about 0.2mm and a length of up to several mm. It can be an autogenous mineral, but it is also seen on the outer edge of altered minerals. Fibrous mordenite gradually separates in a radial pattern. This mordenite should be a modified mineral. The main EDX spectra are Si, Al, Ca, and Na.
3. The SEM characteristic micromorphology of analite is tetragonal octahedron and various forms of polymorphs. The crystal planes are mostly 4 or 6 polygons. The crystal grains can be as large as tens of mm. The characteristic elements of EDX spectrum are Si, Al, Na There can be a small amount of Ca.
Fourth, chabazite SEM characteristic micromorphic short rhomboid column size can be from 1mm to a few mm, EDX spectrum is Si, Al, Ca, there can be a small amount of K, Na. ^[5]

Zeolite

The crystal structure of zeolite can be divided into three components: (1) aluminosilicate skeleton, (2) pores and voids containing exchangeable cations M in the skeleton, and (3) water molecules of latent phase, namely zeolite water.

The structure of zeolite is somewhat different from that of quartz and feldspar. The framework structure of quartz and feldspar is relatively tight, with a specific gravity of 2.6 ~ 2.7, while the framework structure of zeolite is relatively sparse, with a specific gravity of 2.0 ~ 2.2. The dehydrated cavity can be as large as 47%, such as chabazite, or even 50%, such as synthetic zeolite.

In the feldspar structure, metal cations are confined to the interstices of the crystal framework composed of O ions. Unless the crystals are destroyed, these metal cations are difficult to move freely. The exchange of Na or K by Ca must be performed simultaneously with the replacement of Si and Al, that is, the replacement in pairs, which will inevitably cause the change of the Si / AI ratio.

In the feldspar-like structure, metal cations are located in relatively open interconnected spaces with a specific gravity of 2.14 to 2.45. The cations can be exchanged with each other through the structural pathway without damaging the crystal framework. Sodalite and hydrophyllite were once considered zeolite family minerals.

In the zeolite structure, metal cations are located between pores or voids with large crystal structures and interconnected. Therefore, cations can exchange freely through the pores without affecting the crystal framework. Exchanges such as 2 (Na, K) (Ca ²⁺ ) are easy to occur in zeolites and not in feldspar of. This form of exchange may be an extreme form of ion exchange, limited to zeolites and similar minerals.

Zeolite's water molecules are generally loose and weakly related to framework ions and exchangeable metal cations. These water molecules can move and enter the pores more freely than cations. Under the tendency of heat, it can be detached and attached freely without affecting its skeleton structure. ^[6]

Zeolite

Let s talk about the cause: yes

Growth promoting performance

Some related studies have shown that zeolite as a feed additive can promote pig growth performance without negatively affecting pig health. Add 1% to 2% natural in feed

1. Used as feed additive for fish, shrimp and crab. Zeolite contains a variety of macro and trace elements necessary for the growth and development of fish, shrimp, and crab. These elements are mostly in the form of exchangeable ions and soluble bases, which are easier to be absorbed and used. At the same time, they have a variety of biological enzymes.

1. More than 40 natural zeolites have been found all over the world, the most common of which are clinoptilolite, mordenite, chabazite, erionite, phillipsite, zeolite, zeolite, fluorite, and analite. Extensive use has been made of clinoptilolite and mordenite. Zeolite is mainly produced in the fissures or almonds of volcanic rocks, coexists with calcite, pith, and quartz, and is also produced in volcanic clastic sediments and hot spring sediments, mainly using flotation, gravity separation, magnetic separation, etc .;

2. Sodium silicate aqueous solution, aluminum sulfate aqueous solution and tetrapropylammonium bromide (TPABr) are mixed, and the crystallization reaction is carried out at (165 ± 56) ° C and a stirring speed of 90 to 150 r / min for 48 hours, and then separated and washed 2. Drying to obtain the finished product (if the template agent is changed from tetrapropylammonium bromide to tetrabutylammonium bromide, ZSM-1l zeolite can be prepared). ^[8]

Zeolite Dangerous Goods Sign

XnHarmful harmful items

Zeolite Safety Terms

S36 Wear suitable protective clothing.

S2 Keep out of the reach of children.

S26 In case of contact with eyes, rinse immediately with plenty of water and seek medical advice. After accidentally contacting the eyes, immediately rinse with plenty of water and seek medical advice.

Zeolite risk term

R20 Harmful by inhalation. Harmful by inhalation.

R36 / 37 Irritating to eyes and respiratory system.

R36 / 37/38 Irritating to eyes, respiratory system and skin. Irritation to eyes, respiratory system and skin.