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Dissolved organic carbon (DOC) washing has been proved that it could remove heavy metals effectively from contaminated soil. Addition of Ca or Mg into an acid aqueous solution was known promoting the removal for heavy metals. The object of this study was employing mixture solutions prepared using CaCl_2(aq), MgCl_2(aq), and the liquid fertilizer for remediation of a soil severely contaminated with Cr (918 ppm), Cu (1015 ppm), Zn (1105 ppm), and Ni (529 ppm). Effect of Ca and Mg additions on the removal was examined. When soil washings were conducted using the Ca/Mg solutions, only content of Zn remained in soil favored the level of control standard. The DOC substantially elevated removal efficiency of metal during the washing. Two soil washes using a 4000 ppm DOC/0.1M CaCl₂/0.1M MgCl₂ solution with a of pH 2.0 at 25°C removed approximately 68%, 70%, 69%, and 9% of Cu, Ni, Zn, and Cr respectively. Combined action from the Ca²⁺, Mg²⁺, and proton replacements as well as the organic complexation brought the removal of metals to a maximum level.

In this paper, to investigate a compound casting process for creating Al coating layer for Mg alloy, a computational fluid dynamics (CFD) model is developed using the VOF method to simulate the molten Mg drop impact on the Al substrate at solid state. A spreading factor, which is the ratio to the varied diameter of the Mg droplet after impacting on the Al substrate and its initial diameter before the impact, is used to describe and measure the impact process generated by the Mg drop, which could be divided into several steps: spreading, retracting and oscillating, and equilibrium as final step. Some key parameters are investigated via parametric studies: impact velocities, initial diameters of drop, the temperature of the Al substrate, which have important influences on the quality of compound casting products. The spread diameter of the Mg drop increases when the impact velocity and initial diameter of drop increase. While the impact velocities and initial diameters of the drop are larger than critical values, the liquefied Mg may partially have bubbles. The higher the temperature of the Al substrate is, the larger the spread diameters could be obtained, though oscillating and equilibrium steps take more time to finish in the CFD simulations developed.