Al-Cu-Mg alloys have been widely used as structural materials for the aerospace industry due to their high tensile strength, toughness and good processability [1][2][3][4][5] . The hardness and strength of Al-Cu-Mg alloys are low, and pitting corrosion, intergranular corrosion (IGC) and local corrosion always occur in Al-Cu-Mg alloys [6,7] , which limit their industrial applications. Therefore, improving the comprehensive properties of Al-Cu-Mg alloys has always been the focus of research.Numerous studies have shown that heat treatment can significantly enhance the properties of Al-Cu-Mg alloys [8][9][10] . The standard T6 process can improve the mechanical properties of Al-Cu-Mg alloys, but the improvement is limited. To further improve the mechanical properties of the alloy, Lumley et al. [11] proposed the secondary aging process. The secondary aging process means that the standard T6 process is interrupted for a period at a lower temperature. The secondary aging process is called the T6I4 or T6I6

Wastewater from scheelite flotation tailings slathered a lot of sodium silicate in the flotation process, a large number of silicate minerals residues remain in the wastewater, forming suspension bodies difficult to be naturally subsided. With high concentration of suspended substance and pH of 11 or more, this kind of wastewater belongs to unmanageable mine wastewater. Research shows that, pretreating the waste water with Sulfuric acid and calcium chloride, adjusting pH to 7-8 and adding polyacrylamide on flocculating-sedimentation combined can remove suspended solids effectively, offering theoretical basis for wastewater recycling and disposing mine wastewater, which is of great importance.

The corrosion behavior of ZnAl27 alloys in 35g/L NaCl solution has been studied by electrochemical and immersion corrosion tests. The effects of Cu and Sb on the Tafel curves, electrochemical parameters of free corrosion potential, linear polarisation resistance (LPR) and free corrosion current, of the ZnAl27 alloy have been investigated. The surface morphologies of the alloy after immersion corrosion tests have been observed through SEM. The results indicate that addition of proper Cu can improve its corrosion resistance of the alloy, or the free corrosion potential the corrosion current shift towards the positive and negative,respectively. However, excessive addition of Cu can deteriorate the corrosion resistance of the alloy. On the other hand, the corrosion resistance of the ZnAl27 alloy decreases with the increasing of Sb content.

At present, wet lime - gypsum flue gas desulfurization (FGD) technology is very common in the field of gas desulfurization technology. In addition, wet carbide slag - gypsum FGD and Magnesia FGD are also used. In the process of eliminating SO2, with the first two technology, the byproducts of desulfurization wastewater and gypsum will be produced; With Magnesia FGD, the byproducts of magnesium sulfite and magnesium will be produced. The way to utilize desulfurization wastewater, gypsum and magnesium comprehensively and to achieve circular economy is worth exploring.

To study the dynamic response rule of the western slope in Buzhaoba under explosion, a vibrational wave was imposed on the slope. The FLAC3D program was utilized to simulate the rule. The distribution of stress field and the response of velocity were analyzed after blasting. The simulation result shows that the compressive stress increase step by step with the increase of the depth of slope, and as the elevation increases, the particle velocity appears an amplification effect, and the slope is mainly affected by the self-weight stress, and the blasting has little effect on the slope.