Vermiculite


Also found in: Dictionary, Thesaurus, Wikipedia.
Related to Vermiculite: Vermiculite Concrete

vermiculite

[vər′mik·yə‚līt]
(mineralogy)
(Mg,Fe,Al)3(Al,Si)4O10(OH)2·4H2O A clay mineral constituent similar to chlorite and montmorillonite, and consisting of trioctahedral mica sheets separated by double water layers; sometimes used as a textural material in painting, or as an aggregate in certain plaster formulations used in sculpture.

Vermiculite

A generic name for treated minerals which are used for insulation and fire protection, often as an aggregate in plaster or concrete.

Vermiculite

 

a mineral of the hydromica group with a schistous structure and additional interlaminate molecular water. Upon heating, small vermiform rods are formed from the layers of vermiculite. Chemical composition corresponds approximately to the formula Mgx(Mg, Fe)3 x[AlSi3 O10] · (OH)2 · 4H2O. It crystallizes in a monoclinic system and forms laminated aggregates or large laminated crystals of a golden yellow or brown color. Hardness on the mineralogical scale, 1-1.5; density, 2400-2700 kg/m3. It is not susceptible to pulverization and is similar to graphite in lubricating qualities.

When heated to a temperature of 900-1000° C, vermiculite swells (as a result of flaking of particles under the influence of evaporating interlaminate water), with an increase in volume of 15-20 times. Interlayers of air arising between the scaly layers of the mineral cause low density and high heat-and sound-insulating properties of exfoliated vermiculite. Vermiculite is a product of secondary change in dark micas (biotite and phlogopite). Commercial deposits of vermiculite in the USSR are known on the Kola Peninsula (Murmansk Oblast) and in the Urals (Cheliabinsk Oblast); and abroad, in the USA (Montana, Colorado, Wyoming, North Carolina, and Georgia) and in western Australia. Vermiculite is used in construction for the manufacture of heat-insulating products, sound-absorbing materials, lightweight concrete, and plastering solutions; as a filler in rubber, plastic, paints, chemical pesticides; in the manufacture of antifriction materials; and in agriculture, to improve soil structure.

vermiculite

A natural mica expanded by heat(i.e., exfoliated) to form lightweight thermal insulating
References in periodicals archive ?
After exposure, the larvae were removed from the UP and transferred to plastic cups containing vermiculite with different proportions of neem seed cake (NSC) as follows: control (vermiculite only), 5% (5mL NSC plus 95mL vermiculite), 10% (10mL NSC plus 90mL vermiculite), 15% (15mL NSC plus 85mL vermiculite), 20% (20mL NSC plus 80mL vermiculite), 25% (25mL NSC plus 7mL vermiculite), and 30% (30mL NSC plus 70mL vermiculite).
Endophytic bacterial inoculants that were formulated as dry form in vermiculite and coir dust-based carriers were prepared by re-suspending bacterial pellet of UPMB3 and UPMP3 in 1 L sterile LB medium and mixed thoroughly with either 100 g of vermiculite or coir dust carriers.
The germination test was performed in substrates paper towel (organized in the shape of rolls), on blotting paper, burial in sand, burial in vermiculite, Plantmax[R] and Bioplant[R], at the constant temperatures of 25, 30 and 35[degrees]C and alternated temperatures of 20-30[degrees]C, in four replications with 235 seeds, sown in gerbox, with dimensions of 0.
The substitutions of Si by Al in tetrahedral sheet predominate in vermiculite.
8[degrees]2 0 on heating to 550[degrees]C, which is indicates that the peak was due to a mixed layer mineral of vermiculite illite.
In this work, nanocomposites of rigid polyurethane foam with exfoliated, unmodified vermiculite are synthesized.
It was soon discovered that the vermiculite deposit was contaminated with asbestos.
Armed with cash capital and an ongoing perpetual cash royalty as a result of the sale of its Namekara Vermiculite Mine to Rio Tinto for US$5 million, IBI is capitalizing on its strengths and advantageous positioning within Uganda.
Potting--Prepared planting mixtures usually consist of vermiculite, peat moss and fertilizer plus small amounts of sterile soil.
Now, a study finds that even 16 years after the vermiculite mine closed, area trees hold substantial amounts of asbestos, rendering them hazardous to a separate group of workers.