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Properties of Engineering Materials
Published in Leo Alting, Geoffrey Boothroyd, Manufacturing Engineering Processes, 2020
Leo Alting, Geoffrey Boothroyd
The hardness tests described above are based on one or another form of deformation, but as mentioned earlier, hardness can also be defined as resistance to being scratched. Here the Mohs hardness scale, which is based on an arrangement of 10 minerals in order of ascending hardness (talc 1, gypsum 2, calcite 3, fluorite 4, apatite 5, orthoclase 6, quartz 7, topaz 8, corundum 9, and diamond 10) is used. According to this scale, a given material should be able to scratch any material with a lower Mohs number. For example, glass has a hardness of 5.5; hardened steel, 6.5.
Evolution of a karstic groundwater system, Cave Hill, Augusta County, Virginia: A multi-disciplinary study
Published in Barry F. Beck, Felicity M. Pearson, Karst Geohazards, 2018
Samples of high-calcite content have a high specific gravity owing to a lack of pores. Specific gravity of these samples lies very close to 2.71, the known specific gravity for calcite. On the other hand, the specific gravity of samples of mostly insoluble material is significantly lower (2.0 to 2.4).
Rock Forming Minerals
Published in Aurèle Parriaux, Geology, 2018
Calcite is the essential mineral for the production of lime (calcination product of limestone). Mixed with clays, this calcination produces Portland cement (cement that can be used under water).
Mechanical and microstructural characteristics of cemented paste tailings modified with nano-calcium carbonate and cured under various thermal conditions
Published in International Journal of Mining, Reclamation and Environment, 2023
Othmane Benkirane, Sada Haruna, Mamadou Fall
Recent research work has been carried out to explore the use of nano materials to improve the properties (e.g. strength) of cementitious materials (e.g. concrete, mortar). Calcium carbonate nanoparticles (nano-CaCO3) is one of the admixtures that has been used in the concrete industry lately to improve its sustainability [10]. Calcite is the most stable form of calcium carbonate which can be found naturally in limestone among other minerals such as aragonite and vaterite [10]. Calcium carbonate powder is generally produced as a by-product in stone sawing factories with a typical particle size of 0.5 to 1 μm. Calcium carbonate can also be precipitated through the reaction of carbon dioxide and calcium hydroxide [11,12]. One of its advantages is that it can be produced directly in the cement plants by utilising the CO2 waste from cement production [13]. Also, a replacement of the cement by 2% of nano-CaCO3 has shown to reduce CO2 emission from cement production by 69% [11,14].
Selective Flotation of Scheelite from Calcite Using a Novel Reagent Scheme
Published in Mineral Processing and Extractive Metallurgy Review, 2022
Zhiyong Gao, Jian Deng, Wei Sun, Jianjun Wang, Yunfeng Liu, Fengping Xu, Qinghong Wang
Scheelite belongs to the tetragonal octahedral crystal structure (a = b = 5.25 Å, c = 11.40 Å, α = β = γ = 90.00 °), and (1 1 2) and (1 0 1) surfaces are its commonly exposed planes during crushing and grinding (Hu et al. 2012). Calcite has a trigonal rhombohedral crystal structure (a = b = 4.99 Å, c = 17.07 Å, α = β = 90.00°, γ = 120.00°), and its commonly exposed surface is (1 0 4) (Gao et al. 2017b; Gao et al. 2012). In addition, the Ca properties on the exposed surfaces of calcite and scheelite have been characterized in previous work, as summarized in Table 2. The Ca density on the calcite (1 0 4) surface is 8.22 µmol/m2, which is much higher than those (6.58 µmol/m2 and 5.06 µmol/m2) on scheelite (1 1 2) and (1 0 1) surfaces. This result suggests that more Ca active sites on calcite can interact with PBTCA.
Effect of calcite/activated carbon-based post-combustion CO2 capture system in a biodiesel-fueled CI engine—An experimental study
Published in Energy Sources, Part A: Recovery, Utilization, and Environmental Effects, 2019
Thiyagarajan Subramanian, Ankit Sonthalia, Edwin Geo Varuvel
In the present work, a chamber was designed with an outer shell diameter of 109 mm and lengthof 280 mm as shown in Figure 1. Four wire meshes were placed at equal intervals in the center compartment with length 100 mm. The design of the chamber was such that the back pressure could be minimized and adsorption could be maximized. The activated carbon or calcite was placed on these wire meshes. Activated carbon is a form of carbon which is processed with oxygen such that millions of tiny pores are formed in between carbon atoms which increase the surface area for adsorption (Conesa, Sakurai, and AntalJr 2000). It is produced from carbonaceous materials such as wood, nutshells, coal, and lignite (Hayashi et al. 2002). The activated carbon for the present work was purchased from a water treatment system-developing company. Calcite is found in sedimentary rocks, particularly limestone. It is formed from the shells of dead marine organisms. Studies (Arif et al. 2017; Bikkina 2011; Farokhpoor et al. 2013) show that calcite can be used to capture carbon and store for a long time; however, as per the authors’ knowledge, no study exists on its use in internal combustion engines for capturing CO2 emission.