(NAS Colloquium) Geology, Mineralogy, and Human Welfare (1999) / Chapter Skim
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La Roca Magica, Uses of Natural Zeolites in Agriculture and Industry
La Roca Magica, Uses of Natural Zeolites in Agriculture and Industry
Pages 3463-3470
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From page 3463... ...
The discovery of natural zeolites 40 years ago as large, widespread, mineable, near-monomineralic deposits in tuffaceous sedimentary rocks in the western United States and other countries opened another chapter in the book of useful industrial minerals whose exciting surface and structural properties have been exploited in industrial, agricultural, environmental, and biological technology. Like talc, diatomite, wollastonite, chrysotile, vermiculite, and bentonite, zeolite minerals possess attractive adsorption, cation-exchange, dehydration-rehydration, and catalysis properties, which contribute directly to their use in pozzolanic cement; as lightweight aggregates; in the drying of acid-gases; in the separation of oxygen from air; in the removal of NH3 from drinking water and municipal wastewater; in the extraction of Cs and Sr from nuclear wastes and the mitigation of radioactive fallout; as dietary supplements to improve animal production; as soil amendments to improve cation-exchange capacities (CEC)
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From page 3464... ...
This preference for larger cations, including NH4+, was ex ploited for removing NH4-N from municipal sewage effluent and has been extended to agricultural and aquacultural appli cations (1, 2~. Clinoptilolite and natural chabazite have also been used to extract Cs and Sr from nuclear wastes and fallout.
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From page 3465... ...
In Cuba, mortars for ferrocement boats and lightweight aggregate for hollow prestressed concrete slabs contain indigenous clinoptilolite (13, 144. The mortars have compressive strengths of '55.0 MPa; the ferrocement boats can withstand marine environments.
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From page 3466... ...
Mordenite and chabazite, for example, can withstand the rigors of continuous cycling in acid environments and have been used to remove water and carbon dioxide from sour natural gas. Union Carbide Corporation (now UOP Corporation, Tarrytown, NY)
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From page 3467... ...
, and vegetables currently are supplied to Moscow in the winter from greenhouses that use zeoponic synthetic soils. By using a treated Bulgarian clinoptilolite product, cabbage and radishes have been grown aboard the Russian space station Mir (79~.
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From page 3468... ...
Zeolite cation exchange removes NH4+ from recirculating hatchery waters produced by the decomposition of excrement and/or unused food, much as NH4+ is removed from municipal sewage effluent (83-85J. Phillipsite from the Neapolitan Yellow Tuff was used to remove NH4+ from the effluent from saline water in shrimp-culture tanks (86~.
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From page 3469... ...
In the future, mineral scientists investigating the use of natural zeolites (or of any of the industrial minerals mentioned above) must become more proficient in surface chemistry, cation exchange, biological reactivity, and colloid chemistry if they are to continue to Proc.
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From page 3470... ...
M.S. thesis (Mew Mexico State Univ., Las Crucas, NM)
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