Tauride Carbonate Platform Bauxite Deposits (Turkey) as an Alternative Source for Gallium

<p>Mediterranean type karstic bauxite deposits are considered as the primary source for aluminum (Al) production in Europe. During the Al production, Gallium (Ga) is extracted from the so called Bayer-liquor during the processing of bauxite to alumina. Ga, a rare metal, is widely used in modern chemistry and electronic industry. During the past decades, the worldwide demand for Ga has been continuously increasing. In Turkey, karstic bauxite deposits are generally found with shallow marine carbonate rocks which were deposited during Mesozoic period and located in Tauride Carbonate platform. Most of these karstic bauxite deposits can be hosted considerable Ga enrichments, with other immobile elements such as rare earth elements (REE), titanium (Ti), lithium (Li), and iron (Fe). This work focuses on the revealing of the potential Ga enrichments in bauxides from different deposits of Turkey (Mortaş-Doğankuzu, Konya; Küçükkoraş, Karaman; Acıelma-Yoğunoluk, Kahramanmaraş bauxite deposits). Geochemical data of major and trace elements of studied bauxite deposits show that these deposits have significant Ga enrichments (up to 72.6 ppm), as well as the REE (up to 580 ppm), Ti (up to 1.8%), and Li (up to 428 ppm) enrichments. In addition, the Ga enrichments show strong positive correlation with heavy rare earth elements (HREE) and moderate positive correlation with Al, Fe, Ti, Li and Sn elements. In this context, it can be concluded that the most probable source for Ga is rock forming aluminosilicates of the source rock due to the substitution with Al<sup>3+</sup> and Fe<sup>3+</sup>. During weathering process Ga exhibiting immobile behavior much like Al and Fe. Gallium is than incorporated into Al-bearing phases and thus enriched in the bauxite. Presence of Li content can be also interpreted as a contribution from micaceous source such as meta-carbonate rocks of Tauride platform. Moreover, geochemical association between Ga, Ti, Li, tin (Sn) and HREE can be explained by the redox and pH conditions causing other ions seperated from shallow environments.</p>

The Analysis of Bayer Liquor by SPME-GC-MS of Derivatized Organic Poisons

The aim of this article was the gas chromatography–mass spectrometry (GC-MS) analysis oforganic matter from a residual liquor sample (S.C. Alum S.A., Tulcea), extracted by the solid-phasemicroextraction method (SPMA) and derivatized with N-(tert-butyldimethylsilyl)-Nmethyltrifluoroacetamide(MTBSTFA) as the silylating agent. [...]

Hydrothermal Resource-saving Processes in Complex Processing of Bauxite and Red Mud

The Bayer bauxite residue (red mud, RM) is environmentally hostile and hazardous to human health. Red mud can be viewed as an important and promising source of scandium, yttrium, zirconium and other elements rather than a solid waste. Due to a high content of iron in bauxites and especially in RM, the conversion of hematite into magnetite in Bayer liquor plays a key role in the exploration of a cleaner technology of alumina production. Thus, RM and raw bauxite were used for hydrothermal digestion in an original one-stage method of magnetite production during co-recovery of alumina. The yield of alumina reaches 80% from RM and more from bauxites during digestion with addition of lime and Fe(II) or Fe . The saturation magnetization of a bulk sample of magnetized bauxite is 40.5 emu/g, two orders of magnitude higher than that of a raw red mud sample. Moreover, magnetite containing a residue has a high crystallinity, which contributes to better deposition and magnetic separation in the development of an overall flowsheet for RM utilization. Keywords: Red mud, bauxite, hydrothermal treatment; enrichment, extraction, magnetization, hematite, magnetite, rare elements

Flower-like boehmite nanopowders obtained at low temperature from Bayer liquor

Boehmite nanocrystalline powders were obtained by neutralization of Bayer liquor at 70?C with addition of glucose. Temperature of the neutralization induced formation of the flower-like morphology of the nanopowders. XRD and FTIR results confirmed that the single phase boehmite is formed without any other impurities. Calcination at 500?C led to the formation of transition -alumina with the retention of the flower-like morphology. Both as-synthesised and calcined powders possessed high specific surface area with mesopores between 3-6 nm in diameter. Relatively low temperature of neutralization as well as the use of low cost and ecologically friendly glucose as a surfactant are very promising for the possible application in the industrial production of alumina nanopowders.