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Mineral Deposits
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
Typical granites contain about 8 wt% aluminum. Chemical weathering, such as described above, can increase the aluminum concentration to between 25 and 30 wt%—a concentration factor of three to four. Thus, a warm climate and lots of water can transform normal granite into a reddish aluminum-rich soil, like the soil shown in Figure 13.13. This aluminum-rich soil is called laterite. Laterites commonly lithify partly, or completely, to become a rock, and some geologists use the term laterite as both a soil name and a rock name. Lateritic rocks that are particularly enriched in aluminum, like the deposit shown in Figure 13.13, are called bauxite. Thus, laterites and bauxites are the residue left behind after chemical weathering of granite. And, in bauxite, the aluminum that was originally in orthoclase and albite is in aluminum hydroxide minerals, including primarily boehmite, diaspore, and gibbsite.
Research on selective grinding behaviors of bauxite
Published in Wang Yuehan, Ge Shirong, Guo Guangli, Mining Science and Technology, 2004
Wanzhong Yin, Yuexin Han, Xinchao Wei, Zhitao Yuan, Fujia Yu
It is feasible to carry out selective grinding for the typical diaspore type bauxite of China because of its characteristic. Firstly, diaspore with hardness of 6.5–7 is the main aluminum-bearing minerals in the bauxite, while the main silicon-bearing minerals are kaolinite, illite, pyrophyllite etc., whose hardness is smaller than 3 normally. It means there is distinct hardness difference between aluminum-bearing and silicon-bearing minerals. Secondly, Wu Guoliang et al. (Wu et al. 2000) carried out conventional bench grinding experiments for diaspore and kaolinite, which showed that the difference in generation rate of −75 µm product is very big for diaspore and kaolinite. Zhang Guoxiang et al. (Zhang et al. 1982) carried out experimental research for comminution properties of diaspore, kaolinite and limonite. It was shown that the grindability order, from difficult to easy, under longer grinding time, is diaspore > limonite > kaolinite. To make comparison, the content of new produced −75 µm fraction of kaolinite is higher than that of diaspore and limonite. It was proved that desilication by selective comminution was effective through trial test of actual ore. Finally, Liang Anzhen et al. (Liang & Li 1982) carried out selective comminution experiments with the materials of Pinguo Nadou Bauxite Mine with A/S 5.61. After the materials were ground selectively, A/S of +0.037 mm coarse size fraction reached to 9.76, and the yield was 46.49%. The former Soviet Union (Li & Chen 1979) carried out selective grinding experiment with bochmit of A/S 9.3 in run-of-mine. A/S of +0.044 mm concentrate is 6.20 with the recovery of alumina 73.8%.
Comparison and evaluation of alumino-silicate samples as a dual source of alumina and potash values
Published in Canadian Metallurgical Quarterly, 2023
The variation in the aluminum extraction from the silicate rocks with milling time is shown in Figure 5c. As expected, the extraction values showed an increasing trend with time which saturated on prolonged milling. The mica and sericite samples yielded better Al extraction (75-80%) than diaspore and feldspar (40-45%). The better response of mica and sericite can be attributed to the amenable muscovite phase contributing a major fraction of aluminum in the feed. Mohr's hardness of the muscovite is 2-2.5, whereas diaspore and microcline have approximately 7 and 5, respectively. The variation in the potassium extraction with milling time is shown in Figure 5d. A similar trend was observed in the samples as aluminum. However, it was observed that the diaspore yielded better extraction values compared to mica and sericite. The maximum potassium extraction of 71% was achieved after 8 h milling in diaspore. The better response of the mica and diaspore samples can be attributed to the amorphization of the muscovite phase, which is the only contributor to potassium values in both samples.
Overview On Extraction and Separation of Rare Earth Elements from Red Mud: Focus on Scandium
Published in Mineral Processing and Extractive Metallurgy Review, 2018
Ata Akcil, Nazym Akhmadiyeva, Rinat Abdulvaliyev, Pratima Meshram
The mineralogical composition of red mud includes aluminum oxide (boehmite, diaspore), ferrous minerals (hematite, goethite, and limonite), rutile, anatase, pyrite, calcite, and dolomite. Apart from that, the new phases formed during the Bayer process, i.e., sodalite, gibbsite also forms the mineralogical composition of red mud.
Selective adsorption of lead(II) from aqueous solution
Published in Environmental Technology, 2022
Viet Anh Hoang, Syouhei Nishihama, Kazuharu Yoshizuka
Efficient separation methods for the hazardous metals from water environment are still an active issue, according to the increase in stringent regulations for such metals. Many separation techniques have been reported for the removal of Pb(II), such as precipitation [5], ion exchange [6,7], adsorption [8–10] and membrane separation [11]. Adsorption has been gaining more attention due to low cost, efficiency and high selectivity [10]. Various studies have been performed for the adsorption of Pb(II) using various adsorbents, such as activated carbon [2], chelating resins [6,12], cation exchange resin [13], carbon nanotube [14], waterworks sludge [15], magnetite [16,17], hematite [18], zero-valent iron [19] and goethite [9,10,20]. Chelating resins are particularly useful, due to high adsorption capacity and regeneration ability. Liu et al. and Dinu et al. have synthesized iminodiacetic acid (IDA) chelating resin for the removal of Pb(II) and several heavy metals from aqueous solution. The IDA chelating resin has high adsorption capacity for Pb(II), Cu(II), Zn(II) and Cd(II) [6,12]. However, the chelating resins are quite expensive, due to difficulty of synthesis, and adsorption rate was very low [6,12]. Goethite, which is a natural oxyhydroxide, has an isostructural with diaspore which is based on hexagonal close packing and consists of a large amount of reactive surface hydroxyl sites. Mohamed et al. and Rahimi et al. have prepared goethite via precipitation technique and have investigated the adsorption performance of Pb(II) from aqueous solution. Goethite was proved to be effective for the removal of Pb(II), although the selective adsorption of Pb(II) from contaminated water was not revealed [9,20]. Magnetite, a ferrite compound with a cubic inverse spinel structure, has been also recently paid attention. Wang et al. have reported that the effective removal of Pb(II) by magnetite nanoparticles could be achieved, due to high specific surface area and the presence of hydroxyl groups as reactive sites [17]. Yana et al. have prepared magnetite nanoparticle via chemical co-precipitation technique and have revealed the magnetite nanoparticles possess high affinity for Pb(II) [16]. Although the adsorption of Pb(II) from water environment has been studied, using magnetite, goethite and chelating resin, as mentioned above, almost all of the reported works are for a single Pb(II) solution, but not for multi-components system. The adsorption of Pb(II) from multi-components system is required to develop the separation process of Pb(II) from polluted water environment [6]. Accordingly, the low-cost adsorbent with high selectivity for Pb(II) is required. In addition, based on our literature survey, only limited publications have focused on chromatographic separation for the adsorption of Pb(II) from the multi-components system.