In the present investigation, Al-5Zn-2.5Mg - 1.6Cu -xSn (x = 0.0, 0.2, 0.4, 0.6, 0.8, and 1.0 wt. %) alloys were fabricated using melting and casting technique. The microstructures of the alloys were studied using optical, scanning electronic microscope/EDS and X-ray diffraction. The corrosion behaviour was performed using electrochemical measurements and immersion tests while the wear behaviour was carried out by pin-on-disc technique. The findings revealed that incorporating Sn to the Al-5Zn-2.5Mg alloy improved its corrosion and wear resistance due to refining the grains. The corrosion potentials shifted from -884 to -943,-955, -996,-1008 and -1012 mV (Ag / AgCl), while the coefficient of friction declined from 0.69 to 0.62 , 0.51 , 0.34, 0.29 and 0.22 with increment of Sn content from 0.0 to 0.2, 0.4. 0.6, 0.8 and 1.0 wt%, respectively. On the other hand, the results illustrated that the wear rate diminished from 4.42 *10 -3 to 1.47 * 10 -3 (mm3/Nm) with increasing Sn from 0.0 to 1.0 wt%. Furthermore, the findings showed that increment of Sn content stimulated the uniform corrosion on the surface of alloys.

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Gibbsite-bearing shale ore, South Western Sinai, Egypt has been identified as containing physically adsorbed rare earth elements (REEs). The investigated material mainly contains an average rare earth elements (REEs) concentration of 6350 ppm. In spite of low grade compared to other rare earth elements (REEs) sources, the low mining cost and the ease of exploitation make it a promising source of rare earth elements (REEs). In this study, experiments were conducted to investigate desorption of rare earth elements (REEs) via ion-exchange mechanism using monovalent electrolyte solution of ammonium sulfate. All laboratory experiments were conducted at ambient temperature by using a batch leaching technique. The impact process factors that affect the leaching of rare earth elements (REEs) such as the ionic strength of (NH 4 ) 2 SO 4 , the solution's pH, liquid/solid (L/S) ratio and the reaction contact time have been optimized. Rare earth elements (REEs) maximum leaching efficiency of 93.8% was achieved with combination of 0.5 M (NH 4 ) 2 SO 4 , 30 minutes contact time, L/S ratio of 3:1 at pH 5. The selectivity of REEs has been enhanced and improved as a result of the fast-leaching rate and the ease of the ion exchange process. The simplicity with which REEs can be desorbed from gibbsite surface by ion exchange is due to that the rare earth cations are more hydrated than NH 4 + monovalent cation which results in attachment of NH 4 + to gibbsite surface and desorption of rare earth cations to the liquid phase.

In this paper, Egyptian zircon was decomposed through the alkali fusion process to obtain the insoluble product (sodium zirconate) for developing the performance of Al alloy. For this purpose, Egyptian zircon was mixed with NaOH at specific ratios on the stainless steel crucible for starting the opening process. Several parameters such as NaOH /Zircon ratios, fusion temperature, and fusion time were investigated to obtain the optimum conditions to prepare sodium zirconate. Next the Al alloy was melted and sodium zirconate particles were added while stirring. Characterization of zircon opening products was performed by X-ray Diffraction, Scanning Electron Microscopy, and Energy Distributed X-ray. Also, the effect of insoluble product of the zircon opening product on the performance of Al alloy was evaluated via hardness and wear resistance tests. The results demonstrate that the optimum alkali fusion parameters to obtain high recovery of sodium zirconate were as follows; 1.5 NaOH/ZrSiO4 ratio, 650 •C as fusion temperature, and 3 hr as fusion time. On the other hand, adding 5% of sodium zirconate to Al molten metal leads to increasing in the hardness value and the wear resistance over than the value of Al alloy.

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