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Market Potential Assessment of Gypsum Industry
Published in Manjit Singh, Gypsum & Gypsum Products, 2023
Crude vermiculite contains innumerable microscopic droplets of moisture between its lamiae, and, when particles of it are subjected to high temperatures, the moisture in these is converted to stream, and the particles caused to exfoliate (expand) up to fifteen times their original thickness into cellular accordion-like granules with myriad air cells. This characteristic gives exfoliated vermiculite its excellent insulating properties and is responsible for its very light weight.
Mining operations in the Northern Territory of Australia
Published in Tad S. Golosinski, Mining in the New Millennium Challenges and Opportunities, 2020
The mine is owned by Australian Vermiculite Industries Limited. In 1998/99 Mud Tank produced over 10,000 tones of vermiculite from 42,000 tones of ore. Vermiculite is widely used in the construction and agriculture industries.
Inorganic Polymers
Published in Charles E. Carraher, Carraher's Polymer Chemistry, 2017
Vermiculites are formed by the decomposition of mica. They contain layers of water and magnesium ions in place of potassium ions. When heated to 800–1100°C, vermiculite expands because of the conversion of water to gas. The expanded vermiculite has low-thermal conductivity and density and is used as a thermal and sound barrier and as an aggregate in lightweight concrete. It is also used as a moisture-retaining soil conditioner in agriculture.
The effect of vermiculite and quartz in porous concrete on reducing storm-runoff pollution
Published in ISH Journal of Hydraulic Engineering, 2021
Armin Azad, Sayed-Farhad Mousavi, Hojat Karami, Saeed Farzin, Vijay P. Singh
Vermiculite (MgFe3+ Al)3 [(OH) 2 – Al1.25 Si2.75 O10]. Mg0.33 (H2O)4 is a collection of minerals with a laminar texture and a relatively low hardness (about 1.5 in the Mohs scale). Raw vermiculite is less used and a deliberately consumed expandable. Vermiculite is used in agriculture as a moisture adsorbent and porous agent in the soil due to its porous structure. Further, this mineral is used in building materials for production of light concrete, because of its low specific weight (about 450 kg/m3). On the other hand, vermiculite has a very high thermal resistance (about 1100°C), which is used as an insulator for steam boilers and making furnaces. It is noted that this mineral is chemically neutral and is an appropriate insulator for heat, sound, and electricity (Carbajo et al. 2015). In recent years, many studies have been carried out on the use of vermiculite to improve runoff and domestic and industrial wastewaters (Dizadji et al. 2013; Hashem et al. 2015; Prakash et al. 2017). The vermiculite, used in this study, was expanded using a rotary oven at 560°C, and its textures were expanded up to 23 times, along their schistosity. Chemical analysis of used vermiculite is presented in Table 1.
Experimental analysis and modeling of the thermal conductivities for a novel building material providing environmental transformation
Published in Energy Sources, Part A: Recovery, Utilization, and Environmental Effects, 2020
Fatih Koçyiğit, Fatih Ünal, Şermin Koçyiğit
Vermiculite is a clay mineral with volumes of magnesium-aluminum-iron silicate, which is obtained from volcanic magma sources and formed by natural wear of the mica. When vermiculites are heated to high temperatures 900–1000°C very quickly, expanded vermiculites with a bulk density of 56–192 kg/m3 can be obtained due to the sudden evaporation of water between their layers (Li, Yang, and Zok 2013). Vermiculite mineral has a mica-like lamella structure that expands rapidly when heated to produce a light material. Expanded vermiculite has very low density, good thermal and acoustic insulation properties. It is also a chemically inert and fire-resistant material. Because of these properties, it is preferred as a light aggregate for thermal insulation applications (Koksal et al. 2012; Okada et al. 2008; Peletskii and Shur 2007; Suvorov and Skurikhin 2002, 2003). Vermiculite was obtained from Demircilik vermiculite quarry (in Yıldızeli, Sivas, Turkey). The expanded vermiculite was obtained by heating the raw vermiculite for 20 s at 800°C. The expanded vermiculite was initially subjected to pretreatments such as drying, milling and sieving. In this study, raw materials with a particle size of smaller than 200 μm were used for production.
Catharanthus roseus potential for phyto-stabilizing metals in sewage sludge
Published in Journal of Environmental Science and Health, Part A, 2020
Érica S. Barbosa, Ane P. Cacique, Gevany P. de Pinho, Flaviano O. Silvério
It can also be seen from Table 2 that the nine metals were quantified and monitored in the sludge:vermiculite mixture and the As, Ba, Cd, Cr, Ni, Pb, and Se concentrations were very similar to the sewage sludge. This result showed that vermiculite does not release toxic metals into the system, acting as a soil conditioner and aiding in water retention in the system.[18]