The Ionic State of Molybdenum in Sulfuric Uterine Solutions of Rhenium Sorption and its Extraction

results of studies of the forms of finding and methods of extracting molybdenum from acidic solutions with a high concentration of sulfuric acid are presented. Ion-exchange resins of various modifications were tested to determine the most effective for molybdenum during its sorption from a sulfuric acid solution.

Ionic State of Molybdenum in Sulfuric Uterine Solutions of Rhenium Sorption and its Extraction

The results of studies of the forms of finding and methods of extracting molybdenum from acidic solutions with a high concentration of sulfuric acid are presented. Ion-exchange resins of various modifications were tested to determine the most effective for molybdenum during its sorption from a sulfuric acid solution.

Citric Acid as an Alternative to Sulfuric Acid for the Hard-Anodizing of AA6061

Hard-anodized is a widely used method in the aeronautical sector to improve aluminum alloys abrasion and corrosion resistance. Aim of this work was to characterize the mechanical properties and resistance hard-anodized aluminum 6061 in citric acid solution as a replacement sulfuric acid solution were investigated. Aluminum alloy 6061 was used as the base material to produce the hard anodizing; this process was carried out in a citric and sulfuric acid solution, applying current densities 3 and 4.5 A/cm2 and subsequently exposed to 3.5 wt. % NaCl solution. Microstructure and mechanical properties of the anodizing material were characterized by scanning electron microscopy (SEM) and Vickers microhardness (HV). Corrosion behavior of the hard-anodized material it was carried out with electrochemical techniques as cyclic potentiodynamic polarization (CPP) and electrochemical impedance spectroscopy (EIS) respectively. Results obtained indicated that all samples anodized in citric acid solution showed negative hysteresis and lower corrosion current density (1 × 10−10 A/cm2), indicating generalized corrosion on the material surface. EIS results show that anodizing in citric acid solution and a current density of 4.5 A/dm2 provides better corrosion protection than a sulfuric acid solution.