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Structural and Functional Prototypes
Published in Debasish Sarkar, Ceramic Processing, 2019
Sangeeta Adhikari, Debasish Sarkar
Another ceramic that can be used as grinding media is zirconium silicate, which has a strong molecular bond, formed due to a reaction between zirconia and silica. It produces wear-resistant materials with high density. These are fabricated by spray granulation followed by iso-pressing or compact pressing. The green bodies obtained after pressing are sintered in a kiln to obtain a non-porous and tough working surface. This is extremely suitable for milling slurries with low to intermediate density, and it minimizes contamination during milling [11]. Grinding balls of ceria-doped zirconium oxide are mostly used to refine metals such as gold and silver. The major specificity is the content of tetragonal zirconia polycrystalline, which makes it a tighter, and tougher material exhibiting high strength with high wear resistance. These are even stronger than zirconium silicate balls as the difference in hardness is huge. The physical characteristics of these grinding media is presented in Table 10.1.
Silica-free zirconia from zircon mineral by thermal plasma processing
Published in Materials and Manufacturing Processes, 2021
S. Manikandan, A. Kuberan, S. Yugeswaran, P.V. Ananthapadmanabhan, K. Navaneetha Pandiyaraj, X. Sahaya Shajan, P. Balraju
Zircon or zirconium silicate (ZrSiO4) is the major source for production of zirconium oxide (ZrO2) and zirconium (Zr) metal. Ceramic zirconia is being widely used as refractories and as glazing materials due to its unique thermo physical properties in high temperature environments. Due to its biocompatibility and mechanical properties it is an imperative biomaterial for implant applications. Further, zirconia is also used in a wide range of structural applications and emerging engineering applications. Pure zirconium metal and its alloys find applications in the nuclear industry.[1–4] ZrSiO4 is separated from other mineral impurities by standard ore dressing and ore concentration processes and then processed to produce ZrO2. Different kinds of metallurgical processes and chemical routes have been developed to produce ZrO2 from ZrSiO4.[5–8]Among them, high temperature digestion of ZrSiO4 with alkali, followed by separation of ZrO2 after leaching the sodium silicate is one of the promising approaches to recover ZrO2 from ZrSiO4. Meantime, consumption of large quantity of chemical effluents and production of high amount of sodium oxide as a by-product are the major environmental issues, which have to be addressed properly. Hence, there is a demand for alternative methods to recover ZrO2 from zircon mineral in an eco-friendly and cost-effective manner.[9]