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Prediction of Acid Mine Drainage Formation
Published in Geoffrey S. Simate, Sehliselo Ndlovu, Acid Mine Drainage, 2021
James Manchisi, Sehliselo Ndlovu
However, the use of total sulphur (mainly a sum of sulphate and sulphide species) to estimate AP in mine wastes is considered as a conservative approach because not all forms of sulphur produce acid (Morin and Hutt, 2001). For example, the sulphate form of sulphur or simply sulphate-sulphur in gypsum, anhydrite and barite minerals does not generate acid, but sulphate in jarosite, alunite and melanterite is acid generating. The sulphide form of sulphur or sulphide-sulphur that generate acid occurs mainly in iron sulphide minerals (pyrite, pyrrhotite, arsenopyrite) and chalcopyrite, but chalcocite and covellite yield less acid than pyrite while sphalerite and galena may not yield acid at all (refer to Chapter 3 as well). Furthermore, organic sulphur (in coal mines) does not produce net acidity (Price, 2009; Jones et al., 2016). Thus, the use of total sulphur may overestimate the AP in a sample. For these reasons, the modified ABA (or Sobek) method uses sulphide-sulphur rather than total sulphur in Equation 2.1 to estimate AP (Coastech Research, Inc., 1989).
Multicomponent Transport Through Soil Subjected to Coal Pile Runoff Under Steady Saturated Flow
Published in Robert F. Keefer, Kenneth S. Sajwan, Trace Elements in Coal and Coal Combustion Residues, 2020
M. A. Anderson, P. M. Bertsch, L. W. Zelazny
Sodium breakthrough was rapid and sharp (Figure 5: Na), quickly returning to a concentration near that of the influent (Table 1), and provides an interesting contrast to that of K. Both Na and K are relatively minor components of the exchange phase of the samples (Table 5), and are monovalent. Yet the K peak for all samples is retarded and also greatly broadened relative to Na (Figure 5). Considerable research has established, however, that a number of 2:1 clay minerals have a high selectivity for K over other common soil cations.31 Due to its low hydration energy and size, which allows it to fit easily into hexagonal holes within Si tetrahedral layers,31 K can participate in fixation reactions with certain 2:1 phyllosilicate minerals (e.g., vermiculite) found within these materials (Table 4). The observed retardation of K relative to Na thus may be a result of K sorption to these highly K-selective sites, though precipitation within an alunite or jarosite phase can not be discounted.
Humidity Sensor Based on Alum–Fly Ash Composite
Published in Amit Sachdeva, Pramod Kumar Singh, Hee Woo Rhee, Composite Materials, 2021
Amit Sachdeva, Shri Prakash Pandey, Pramod K. Singh
The most common alum is the double sulfate of potassium and aluminum, K2Al2(SO4)4.24H2O, a white crystalline powder that is readily soluble in water. It is used in curing animal skins. Other alums are used in papermaking and to fix dyes in the textile industry. The raw material of manufacture of common alums is alum rock, composed chiefly of alunite or alum stone. Alum is also made from alum shale, which is either allowed to decompose by exposure, or roasted. During the process, free sulfuric acid is formed, which acts upon the clay, producing aluminum sulfate, which is then dissolved out. Potassium sulfate or ammonium sulfate is added to the solution to produce potash alum or ammonia alum.
Identifying hydrothermally altered rocks using ASTER satellite imageries in Eastern Anti-Atlas of Morocco: a case study from Imiter silver mine
Published in International Journal of Image and Data Fusion, 2022
Youssef Atif, Abderrahmane Soulaimani, Atman Ait lamqadem, Amin Beiranvand Pour, Biswajeet Pradhan, El Aouad Nouamane, Kharis Abdelali, Aidy M Muslim, Mohammad Shawkat Hossain
Crosta technique verified the presence of alteration zones that have been mapped using band ratio method in the study area. The spatial distribution of iron oxide/hydroxides, argillic, phyllic and propylitic zones were specifically mapped using Crosta technique (see Figure 7). Argillic and phyllic alterations show almost identical spatial distribution, while propylitic zone show wider surface distribution and high level of mixing with argillic and phyllic alterations (see Figure 8). The occurrence of these alteration zones is also identified in the Imiter silver mining zone. The n-dimensional analysis technique showed the presence of haematite/goethite, muscovite/illite, chorite/epidote, jarosite and kaolinite/alunite in the study area (see Figure 9). Fraction images derived from MTMF algorithm show the sub-pixel abundance of the alteration minerals (see Figure 10). High-to-moderate abundance of the alteration minerals is detected in the Imiter mining zone (Baroudi et al. 1999). High abundance of the alteration minerals is found in the alteration zones that delimited by band ratio and Crosta techniques.
Removal and immobilization of arsenic from wastewater via arsenonatroalunite formation
Published in Environmental Technology, 2022
Zhongqiu Luo, Weihong Mu, Xintao Zhou, Zhuo Chen
The alunite supergroup is classified as two distinct phases, the jarosite-type phase and natroalunite-type phase, which can exhibit different immobilization performance for heavy metals. Some studies have conducted on the immobilization of Pb, Zn, Cu, and Cr through formation of jarosite-type precipitation, such as PbFe3(SO4)2(OH)6, Pb(Fe,Zn)3(SO4)2(OH)6, Pb(Fe,Cu)3(SO4)2(OH)6, and KFe3(SO4,CrO4)2(OH)6, respectively [5,6]. Arsenic, a common pollutant with extremely high toxic in industrial wastewater, has also been immobilized by arsenate (AsO4)-for-sulfate (SO4) substitution in jarosite-type compounds (AFe3(SO4)2(OH)6) [7,8]. The degree of AsO4-for-SO4 substitution could reach 4 wt.% in the potassium jarosite (KFe3(SO4)2(OH)6) and 1.5 wt.% in a sodium jarosite structure (NaFe3(SO4)2(OH)6), respectively. However, the jarosite-type (AFe3(SO4)2(OH)6) phases are easy to dissolve when exposed to anaerobic conditions, which can lead to the leaching of arsenic to cause secondary contamination.
Roasting of pyrophyllite for application in aluminoborosilicate glass production
Published in Geosystem Engineering, 2020
Joobeom Seo, Sangbae Kim, In-Kook Bae, Wantae Kim
XRD analyses of the raw pyrophyllite (Py) and the roasted pyrophyllite (RPy) show distinct mineralogical differences (Figure 2). Py is composed of aluminium-bearing minerals, in this case pyrophyllite, dickite, diaspore, and alunite, and quartz. On the other hand, RPy is composed of alumino silicate and quartz, indicating an alternation the pyrophyllite due to the roasting process. The roasting of Py was carried out at 1150 °C for dehydroxylation to reduce the ignition loss and thermal transformation to results different crushing behavior (Li et al., 2014). The chemical compositions of Py and RPy analyzed by XRF confirm the dehydroxylation of pyrophyllite upon the roasting (Table 2).