China
Africa
Explore chapters and articles related to this topic
Characteristics of soils
Published in Yanrong Li, Handbook of Geotechnical Testing, 2019
The solid components in soils are formed by weathering, transportation and sedimentation of parent rocks. Soil-forming minerals can be classified into primary and secondary minerals according to the composition of the parent rock. The soil particles composed of primary minerals have the same properties as those of parent rocks and are usually formed by the physical weathering of parent rocks. The nature of soil particles is relatively stable, has no plasticity and is weak in absorbing water. Common primary minerals are quartz, feldspar, mica, hornblende and pyroxene. Soil particles composed of secondary minerals, whose material composition differs from that of parent rocks, are usually formed from the chemical weathering of parent rocks. Particle size is relatively small and exhibits unstable properties. Soil particles can absorb water. As a result of changes in water content, the volume of soil particles can easily expand or contract. The secondary minerals are mainly clay minerals, the most common being kaolinite, illite and montmorillonite. A small amount of organic matter and soluble salts also exist in soil. The test methods for properties of soil can be found in the specifications GB 50123-1999, BS 1377-3 and ASTM D 2974-14.
Plutonic 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
Secondary minerals include many alteration products of primary minerals. In felsic and intermediate rocks, for example, feldspars and micas commonly alter partially or wholly to epidote, chlorite, or clays. Many secondary minerals are hydrous, forming by reaction of primary minerals with water flowing through a rock. They may form by in situ alteration of an original mineral grain or in secondary veins. The photo in Figure 6.9 shows the Ruin Granite from near Globe, Arizona. The rock contains quartz (gray, but hard to see), orthoclase (pinkish), and plagioclase (white). Individual plagioclase grains are altering to light green secondary epidote; additional epidote is seen in secondary veins. Besides epidote and clays, other common hydrous minerals that form from feldspars include minerals of the zeolite group.
The Groundwater Geochemical System
Published in William J. Deutsch, Groundwater Geochemistry, 2020
In the natural geochemical system, fresh recharge water with few dissolved constituents and low concentrations contacts the subsurface material and interacts with the other phases of the system. Chemical reactions occur because the composition of the recharge water is not in equilibrium with the solid phases or the soil gases. Disequilibrium drives the reactions that dissolve gases and minerals into the water and changes the solution composition. New minerals may precipitate from water as the solution composition becomes saturated with the constituents of secondary minerals. These secondary minerals are weathering products of the dissolution of the primary minerals.
Experimental investigation of linear damping characteristics on granite and red sandstone under dynamic cyclic loading
Published in European Journal of Environmental and Civil Engineering, 2022
Haoteng Wang, Mingming He, Jiwei Zhu, Shuangfeng Guo, Yunsheng Chen, Ning Li
By observing the surrounding rock of the traffic tunnel under construction in the Qinling Mountains, it is found that red sandstone and granite occupy majority of the surrounding rock composition. Due to the typical rock characteristics, the impact of low-frequency and low-amplitude dynamic disturbances on granite and sandstone cannot be ignored. In this paper, therefore, sandstone and granite samples were selected as research objects. Red sandstone mainly contains feldspathic, gypsum and fine-grained sand granules. The granules of sand particle have a size of 0.1 to 0.4 mm, the elliptical shape, their abundance is 86%, and the voids are 14%. The single mineral granules in red sandstone are dominated by potassium feldspar (43% of mineral content). The main minerals of granite are quartz (15% mineral content), feldspar potassium (32% mineral content) and plagioclase (43% mineral content); the secondary mineral is biotite (6% mineral content). According to the ISRM test process and precautions, the rock samples were cut into cylinders 100 mm long and 50 mm in diameter. The evenness of the end faces was controlled to 0.02 mm (Figure 2). The porosity of granite was measured at 0.44%–0.46% and the porosity of sandstone was measured at 1.33%–1.36%. The wave velocity of sandstone was 2518–2596 m/s and the wave velocity of granite was 5010–5108 m/s (Table 1). These differences indicate that the granite distribution of mineral is evidently denser than sandstone.
Wet High-Intensity Magnetic Separators (WHIMS) for Recovering Iron from Tailings Deposited in Dams
Published in Mineral Processing and Extractive Metallurgy Review, 2021
Rafaella Bicalho da Rocha, Érica Linhares Reis, José Pancrácio Ribeiro
To increase the global production of iron ore, countries that produce iron ore are beginning to use low-grade iron ores (Bartinik, Zabel and Hopstock 1975; Ramdohr 1980; King 2001; Li et al. 2010b; Chen et al. 2013; Pinheiro, Filho and Neves 2016; Ribeiro et al. 2017; Yang et al. 2018; Rasool and Lieberwirt 2018). In addition, they are beginning to use fines and slimes, which are traditionally sent to tailings dams to be stored indefinitely due to the inefficiency of the beneficiation process (Li et al. 2010a; Jena et al. 2015; Ozcan and Celik 2016; Tripathy et al. 2017). On average in Brazil, 33% of iron ore is rejected as tailings during beneficiation (Pinheiro, Filho and Neves 2016). However, disposal in tailing dams occupies large tracts of green space, such as forest land and farmland, polluting the environment nearby and presenting a risk of accidents and ruptures (Li et al. 2010a; Zhang et al. 2019). Therefore, it is important to develop new ways to recover more of the iron from iron ore tailings, which currently constitutes one of the most important secondary mineral resources (Mohanty, Nayak and Konar 2017; Uwadiale 1992; Wolff, Costa and Dutra 2010; Yang et al. 2018). The huge quantity of existing tailings, ongoing production of new tailings, and the latest accidents with iron ore tailings dams in Brazil have rendered the utilization of these resources an increasingly urgent topic.
Mineralogical and geochemical characterisation of kaolin deposit from Debre Tabor area northwestern, Ethiopia
Published in Applied Earth Science, 2021
Alemu Mesele, Teklay Gidey, Tilahun Weldemaryam, Wuletaw Mulualem, Tamrat Mekuria, Yahya Ali, Gizachew Mulugeta, Betelhem Tesfaye, Mulgeta Brihan
Considering textural and compositional variations in the rock samples five samples (Table 1) were selected for thin-section analysis. These samples were prepared and analysed at the central laboratory of Geological Survey of Ethiopia (GSE), Addis Ababa. From thin-section analysis, the primary and secondary mineral assemblages were identified using a transmitted light petrographic microscope at the geology department, University of Gondar. Quantitative and qualitative mineralogical examinations of variable kaolin minerals for 15 kaolin samples were done using X-ray Diffraction (XRD) at Adama Science and Technology University, Ethiopia (Table 1). The diffractometer was equipped with a copper tube and operated at 40 kV and 30 mA ranging from 10° to 80° of 2θ for about 1 h per sample. The qualitative phase determination was performed using the Match!3 software while quantitative mineralogy was determined by Rietveld refinement using FullProf Suite ToolBar (FP-Suite-TB) software. The physical tests included: specific gravity, bulk density, and grain size analysis were conducted on nine kaolin samples at the central laboratory of GSE (Table 1). Twenty samples (15 kaolin and 5 felsic rocks (tuff and trachyte)) were also selected for geochemical analysis (Table 1). These samples were submitted to Australia Laboratory Service, which is found in Ireland for major element analysis (using inductively coupled plasma-atomic emission spectrometer (ICP-AES)), and for trace element analysis (using inductively coupled plasma-mass spectrometer (ICP-MS)). About 0.20 g powder sample was mixed with lithium metaborate (LiBO2) flux at 1000°C. The resulting melt was cooled and dissolved in 100 ml of 4% HNO3 and 2% HCL solution. The final solution was aspirated into plasma through a pinhole-sized orifice in a pumped vacuum system and elemental concentrations were recorded by both analytical methods (ICP-MS and ICP-AES). The detection capacity of the methods ranging between 0.01% and 100% for major oxides and 0.01–10,000 ppm for trace elements.