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Toxic Responses of the Lung
Published in Stephen K. Hall, Joana Chakraborty, Randall J. Ruch, Chemical Exposure and Toxic Responses, 2020
The pyroxene group forms chains of (Si2O4)4− units bound together by covalent oxygen bonds. The commercially mined pyroxenes are spodumene and wollastonite. Spodumene, a comparatively rare mineral, is one of the commercial sources of lithium. Wollastonite is used in the ceramic industry, as a replacement for nonfibrous materials in brake linings, as an insulation for electronic equipment and thermal insulation such as mineral wool, and many other uses, There is no known disease associated with exposure.
Metamorphic Rocks
Published in Dexter Perkins, Kevin R. Henke, Adam C. Simon, Lance D. Yarbrough, Earth Materials, 2019
Dexter Perkins, Kevin R. Henke, Adam C. Simon, Lance D. Yarbrough
Figure 10.1 shows a rock from the Willsboro Mine in New York. The large white crystals are lathes of the mineral wollastonite up to 1.5 centimeters in length. The wine-red crystals are garnet, in some places several millimeters in longest dimension. And the small dark green crystals are millimeter-scale diopside. Society uses wollastonite in ceramics, plastics, paints, and for other purposes once served by asbestos. The Willsboro Mine has produced a great deal of wollastonite in the past, but operations shut down in the early 1980s. However, the nearby Lewis Mine is producing more than 60,000 tons of wollastonite, equivalent to 10% of world production, every year.
Effects of Nano-materials on Different Properties of Wood-Composite Materials
Published in Zhongqi He, Bio-based Wood Adhesives, 2017
Hamid R. Taghiyari, Jack Norton, Mehdi Tajvidi
Although the addition of nanosilver and nanocopper were reported to be significantly effective in reducing the growth of wood-deteriorating fungi and improving hardness in particleboard panels, the panel manufacturing industry in Iran did not show much interest to use these metal nanoparticles in their production program for two main reasons: the high cost of preparing silver or copper at nano-scale and the associated cost of applying these expensive metals during the manufacturing process. Therefore, researchers investigated other materials that are cheaper than silver or copper, as well as being abundant in many countries. Wollastonite is a calcium inosilicate mineral (CaSiO3) that may contain small amounts of iron, magnesium, and manganese substituting for calcium. Its color is usually white and its thermal conductivity coefficient is high (Taghiyari et al., 2013a). It is abundant in many countries, including the US, Brazil, China, and Iran. The mineral wollastonite was found to be effective in reducing the effects of certain pathogens, including fungi (Aitken, 2010; Karimi et al., 2013). It is also nontoxic to humans or wildlife. Whilst there was no clear evidence to indicate wollastonite presented a health hazard, long term exposure to wollastonite dust was investigated (Huuskonen et al., 1983a; Maxim and McConnell, 2005). It was reported that the long term health effects due to inhalation of wollastonite appeared to be negligible because no correlation of serum angiotensin-covering enzymes in wollastonite workers with slight pulmonary fibrosis was found (Huuskonen et al., 1983b). Wollastonite gel or powder can be easily applied in the wood- composite manufacturing industry as an IPT, either mixed with the resin or sprayed on wood fibers and particles, and is not considered to be a serious hazard to human health or wildlife (Karimi et al., 2013).
Sustainable ceramics derived from solid wastes: a review
Published in Journal of Asian Ceramic Societies, 2020
Wollastonite (CaSiO3) is the most widely studied calcium silicate mineral. It has some widespread properties such as low thermal conductivity, low dielectric constant and loss, chemical inertness, corrosion resistance, low thermal expansion, fluxing properties, and whiteness [144]. These characteristics of CaSiO3 are made them highly useful in ceramic industries, including metallurgical, paints, plastics, constructions, chemicals, and medicals [145,146]. The ceramic industries are consumed nearly 30–40% of wollastonite worldwide to advances the various performance parameters of ceramics. Therefore, the world demand for this mineral is steadily expanding. But, wollastonite is not available for so many countries, and large deposit mines have not been surveyed yet. Thus, many studies have been performed to synthesize synthetic wollastonite from low-cost waste ingredients through different synthesis techniques. The name of the wastes with process parameters to synthesis wollastonite is tabulated in Table 5.
Study of physical and dielectric properties of bio-waste-derived synthetic wollastonite
Published in Journal of Asian Ceramic Societies, 2018
Wollastonite is a calcium silicate mineral with the chemical formula CaSiO3. According to its crystal structure, it is among the pyroxenoid group of inorganic materials containing infinite chains of [SiO4] tetrahedral [1]. The chain motif in wollastonite is formed by two apex-to-apex combination tetrahedra, one of which is a tetrahedron with a corner parallel to the Si–O chain direction. The Si–O chains are co-ordinated to Ca [2]. It has a polymorphic structure, the most common triclinic or monoclinic phase is a low-temperature phase, i.e. β-CaSiO3 (para wollastonite), and the other is a high-temperature phase, i.e. α-CaSiO3 (pseudo wollastonite) [3]. Some properties of wollastonite, i.e. its low dielectric constant, low dielectric loss, low volatile content, high brightness, whiteness, low shrinkage, low thermal expansion, low moisture absorption, thermal stability and fluxing properties, are highly useful for industrial applications [4]. The use of wollastonite by the ceramics industry to obtain ceramics with better performance parameters is increasing rapidly, improving sales results worldwide by 30%–40%. It also offers useful applications for other industries, such as applications as a metallurgical flux for welding, as an additive in paints, as plastics to improve tensile and flexural strength, as a material for civil construction, and as a medical material for artificial bones and dental roots [5,6]. World demand for wollastonite is therefore steadily expanding.
The effect of titanium oxide and hydroxyapatite on the mechanical properties of wollastonite
Published in Cogent Engineering, 2019
D. Ragurajan, M. Satgunam, M. Golieskardi, U. Sankar, Angela Min Hwei Ng
Bone-related diseases as well as injuries have become quite frequent in recent times. Due to strenuous activities, bones are under a lot of stress, especially load-bearing bones such as the femur and tibia, and as a result the bone fractures and the surrounding tissues are damaged. This has lead to researchers attempting to develop a biomaterial which is capable of imitating a real bone particularly in terms of durability and reliability (Garcia, Miranzo, & Sainz, 2018). Biomaterials, however, are unable to partake in the biological processes which are responsible for bone formation and remodelling (Copp & Shim, 1963). The selection of a biomaterial is crucial in determining the outcome of the biological events that take place such as signalling molecules, growth factors and cell migration onto the site of injury (Freyman, Yannas, & Gibson, 2001). Currently, metals have been largely utilized for bone replacements. Over time, the properties of the metal implant may deteriorate as metals may support too much load and eventually experience failure. Besides that, metals may also degrade after a period of time due to its surroundings, which in turn causes the release of metal ions into the human body which may lead to side effects such as toxicity and allergic reactions. Wollastonite is seen as a promising biomaterial due to its properties such as biocompatibility with human cells, compatibility with hard tissues as well as not being toxic (Lin et al., 2005; Magallanes-Perdomo et al., 2010; Risbud, Saheb, Jog, & Bhonde, 2001; Tamimi et al., 2008; Zhang, Molenda, Fournelle, Murphy, & Sahai, 2010). Wollastonite exists in two mineral forms; α-wollastonite (high temperature) and β-wollastonite (low temperature) (Shukur, Al-Majeed, & Obied, 2014; Teixeira et al., 2014). According to researchers, the release of ions from calcium silicates could promote gene expression and aid in the efficiency of insulin-like growth factor (IGF) which is related to cell proliferation. Generally, wollastonite exhibits good mechanical properties such as hardness and compressive strength. However, according to previous studies, it was found that the high dissolution rate of wollastonite proves to be a drawback as it hinders the biomaterial’s use in clinical applications (Aly, Mohammed, Al-Meer, Elsaid, & Barakat, 2016; Liu & Ding, 2002a). Addition of other biomaterials to wollastonite could hinder this problem. In this study, TiO2/CaSiO3/HA composites were prepared and characterized by means of physical and mechanical properties.