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Evolution in the protection of clay-based mortars
Published in Jan Kubica, Arkadiusz Kwiecień, Łukasz Bednarz, Brick and Block Masonry - From Historical to Sustainable Masonry, 2020
In all cases, the manufactured specimens were of 40×40×160 mm dimensions for each series of mortars. The clay used was extracted from the island of Crete and has been characterized using XRD analysis, particle size distribution and chemical analysis. The specific gravity of the dry material is 1.96 g/cm3 (ASTM-C188-95) while the color determination using Munsell charts is 5Y,7/1, light grey. The XRD analysis indicated that the soil particles consisted of quartz, calcite, calcium aluminum hydroxide, cancrinite and a small percentage of muscovite, while a high content of calcium oxide of 25% was reported by the results of the chemical analysis (Table 3). More information on the analysis of the binder, as well as the XRD charts can be found on a previous research paper of the authors (Karozou et al. 2019).
Precipitation and Crystallization Processes in Reprocessing, Plutonium Separation, Purification, and Finishing, Chemical Recovery, and Waste Treatment
Published in Reid A. Peterson, Engineering Separations Unit Operations for Nuclear Processing, 2019
Calvin H. Delegard, Reid A. Peterson
The evaporative processes crystallize the sodium salts contained in the waste solutions, and the imposed alkaline conditions precipitate polyvalent metal ions as their (hydr)oxides, the most prominent of which are gibbsite (Al(OH)3) boehmite (AlOOH), from gibbsite dehydration (see the following section), and hematite (Fe2O3). Sodium aluminosilicates such as cancrinite and sodalite, NaAlSiO4 ∙ xNaX ∙ yH2O, where X is a nitrate or other anion, also are present in both Hanford and Savannah River Site tank wastes. The salts largely are composed of NaNO3 because the Pu and U recovery processes occurred in HNO3, and the waste made alkaline with sodium carbonate (Na2CO3) and NaOH. Other solid salts crystallized in the sites’ tank wastes include Na2CO3, sodium carbonate monohydrate (Na2CO3 ∙ H2O) sodium fluoride phosphate, natrophosphate or (Na7F(PO4)2 ∙ 19H2O) and sodium diuranate (Na2U2O7) (Hobbs and Coleman 1994; Wilmarth et al. 2000; Herting et al. 2015; Reynolds et al. 2013; Peterson et al. 2018).
Applications and case studies
Published in Caijun Shi, Pavel V. Krivenko, Della Roy, Alkali-Activated Cements and Concretes, 2003
Caijun Shi, Pavel V. Krivenko, Della Roy
The hydroceramic waste forms are then autoclaved at 90°C or 190°C, then a dense matrix having sufficient strength to withstand the rigours of stacking in a repository environment is formed. But best of all, the matrix is extremely insoluble. The primary load-limiting characteristic of the hydroceramic waste forms is that cancrinite (or sodalite) represents maximal waste loading; i.e., no more than 25% of the formulation’s sodium can be in forms other than hydroxide, silicate or aluminate.
An overview of the mineralogical characterization and treatment strategies of Bauxite residues for their sustainable management
Published in Mineral Processing and Extractive Metallurgy Review, 2023
Adèle Dramou, Lev O. Filippov, Ndue Kanari, Eric Allain, Sekou Traoré, Inna V. Filippova
The process consists of injecting gaseous CO2 into an aqueous phase of BR to form H2CO3 which then interacts with compounds responsible for the alkalinity (NaOH, Na8(Al6Si6O24)Cl2, AlNa12SiO5 etc.). The interaction leads to the formation of carbonate and bicarbonate responsible for the reduction of the pH below 10 (Khaitan, Dzomback and Lowry 2009). The products of the Bayer process, such as cancrinite (Na6Ca2CO3, Al6Si6O24 · 2H2O) and sodalite (Na8(Al6Si6O24)Cl2) dissociate into sodium aluminate (NaAlO2), sodium silicate (Na₂SiO₃) and sodium aluminosilicate ((Na2O.Al2O3.SiO2) (Agrawal, Rayapudi and Dhawan 2008).
Production of red mud based nanofibers and their potential in arsenate removal from waste water
Published in Journal of Dispersion Science and Technology, 2022
Zeynep Çetinkaya, Volkan Kalem
RM can be considered as a secondary raw material with its suitable components for industrial use. Hematite, sodium aluminosilicate hydrate, cancrinite, sodalite, and diaspore are the main minerals in RM. On the other hand, the alkaline structure of RM causes environmental problems and storage difficulty.[15] RM is an important waste in the production of aluminum, with high concentration of hematite and other minerals, thus promoting further research accordingly. Although various processes have been developed for the removal of RM residue, there has been no practical application yet. Most of the processes used are related to the aluminum industry. RM is widely used in industries such as construction-building, chemistry, agriculture, and ceramics.[16] The recovery of precious metals in the RM is also an important application area.[16,17]
Lightweight composite from fly ash geopolymer and glass foam
Published in Journal of Sustainable Cement-Based Materials, 2021
Ferenc Kristály, Roland Szabó, Ferenc Mádai, Ákos Debreczeni, Gábor Mucsi
According to ATR-FTIR results, hydration state of geopolymer alumino-silicate material (800 to 1000cm−1) and adsorbed/interchangeable H2O (2300 to 3400cm−1) is variable between the samples (Figure 11). These variations and differences can be interpreted in terms of sample specific reactions. As we increase the GB ratio, the ratio of liquid/fly ash also increases, producing stronger geopolymerization. Quartz, mullite and cristobalite are observed only as a shoulder (1000–1200cm−1) on the large band of amorphous alumino-silicate material (900–1000), which is also different from the large band characteristic for fly ash [57]. The range 1300 to 1700 is characteristic for hydrated minerals (zeolites, cancrinite, cancrisilite) but also carbonate minerals, like thermonatrite as we have detected in our earlier research [58]. Characteristic peaks are summarized in Table 4.