Zeolite: A Stone Mineral

Zeolite was originally coined in the 18th century by a Swedish mineralogist christened Axel Fredrik Cronstedt, who revealed that heating a natural mineral that the stones began to progress about as the water evaporated. He called this substance zeolite because of the Greek utterances which means ‘stones that boils.’ Zeolites are microporous and commonly used as commercial adsorbents. Zeolites figure where volcanic rocks and ash deposits respond with Alkaline ground stream. These stone minerals are also crystallized in post depositional surroundings over periods varying from thousands to millions of years in minor marine basins. Zeolites are rarely pure and are contaminated to varying degrees by different forms of minerals, metals, quartz or other zeolite. Zeolite occurring in nature is eradicated from many vital profitable uses where reliability and clarity levels are of high-end and essential.

Moreover, Zeolites are largely used in industry for water purification, as catalysts, and in nuclear reprocessing. Their major use is in the manufacture of laundry detergents, medicine and in agriculture. In November 2010, there were 194 unique Zeolite frameworks have been identified, and over 40 naturally occurring Zeolite frameworks are known.

Sources

In Arkansas and New Mexico, people make use of conventional open pit mining techniques to acquire natural Zeolites. In mining process, the ore is crushed, dried, and milled. The milled ore may be air-classified as to particle size and shipped in bags or bulk. The crushed product may be carefully screened to eliminate fine material when a granular product is required, and some pelletized products are produced from fine material. The world’s yearly production of Zeolites is presently about 4 million tons. And in fact, the world leaders in supplying natural Zeolites are Eastern Europe, Western Europe, Australia, and Asia.

One of the vital processes used to carry out Zeolite synthesis is sol-gel processing. The silicalite sol formed by the hydrothermal method is very stable. Also the ease of scaling up this process makes it a preferred route for Zeolite synthesis.

Uses

Zeolites are widely used as ion-exchange beds in domestic and commercial water purification and softening. Zeolites have the capacity to provide precise and specific separation of gases including the removal of water from low-grade natural gas streams.

In Petrochemical Industry, Zeolites are widely used as catalysts in the petrochemical industry, like for example in fluid catalytic cracing and hydro-cracking. Furthermore, Zeolites confine molecules in small spaces, which causes changes in their structiure and reactivity. The hydrogen forms of Zeolites are strong solid state acids, and can facilitate a host of acid-catalyzed reactions, such as isomerisations and alkylation

In Nuclear Industry,  Zeolites have many uses in reprocessing methods, where their micro-porous ability to capture some ions while allowing others to pass freely allow many fission products to be efficiently removed from nuclear waste and permanently trapped. Fission products, the zeolite-waste combination can be hot pressed into an extremely durable ceramic form, closing the pores and trapping the waste in a solid stone block.

In heating and refrigeration, Zeolites can be used as solar thermal collectors and for adsorption refrigeration. The heat of adsorption and ability to hydrate and dehydrate while maintaining structural stability is exploited.

Detergents

The largest single use for Zeolite is the global laundry detergent market. This amounted to 1.44 million metric tons per year of anhydrous Zeolite in 1992.