Chlorine fluxing for removal of magnesium from molten aluminum: Part I. Laboratory-scale measurements of reaction rates and bubble behavior

Abstract

Chlorine fluxing is widely used in the aluminum industry for the removal of magnesium from molten aluminum. Typically, it consists of bubbling a nitrogen/chlorine or argon/chlorine mixture into the melt. This Part I of a two-part article describes laboratory-scale experiments on the kinetics of the reactions and emissions during chlorine fluxing for magnesium removal. Bubble frequency, size, and residence time were measured by a two-microphone detection system, which lead to an estimate of the melt-gas interfacial area. Emissions were found to be low, provided the melt temperature was above the melting point of magnesium chloride and provided the magnesium content was above a critical level. Experimental results suggested the chlorine supply to be the rate-determining factor above this critical level and magnesium mass transport to be the rate-determining factor below the critical level.

Removal and Recycling of Antimony from Liquid Copper by Using CuCl-CaO Fluxes at 1423 K

“…The chlorination refining by chlorination reaction is effective for the recycling of aluminum scrap [7] and refining of crude lead. Moreover, the chlorination reaction with chlorine gas or chloride is also used for the treatment of waste such as the dust from metal industry.…”

Mechanisms of Oxidation and Vaporization of Antimony from Liquid Copper with CuCl–CaO Fluxes

“…Since SbOCl was confirmed in flux as shown in Fig. 4, the antimony may vaporize as SbOCl into gas phase as well as Sb 4 Figure 7 shows the XRD patterns of collected dusts from the vaporization of these two fluxes. The XRD peaks for antimony chloride and antimony oxychlorides were observed, which suggests the vaporization of Sb from flux as chloride and oxychloride.…”

“…4,5) For the recycling of copper scrap, Tsukihashi and Hatta, 6) and Iwasaki and Tsukihashi 7) reported that the partition ratios of Fe and Pb between CuClbased flux and liquid copper increased with increasing the content of Na 2 CO 3 , CaO or BaO in CuCl flux at 1 473 K, and a part of removed Fe and Pb vaporized to gas phase. Mochida and Mikuni 8) also reported that the concentration of Fe, Pb, Zn or Sn in copper largely decreased with time by using Ar-10%Cl 2 mixture at 1 473 K. Therefore, the chlorination reaction is effective for the removal of impurities from liquid copper.…”

Removal of Antimony from Liquid Copper by Using CuCl–Na2CO3 Fluxes at 1423 K

“…7,8) For the recycling of copper scrap by chlorination reaction, Tsukihashi and Hatta, 9) and Iwasaki and Tsukihashi 10) reported that the partition ratios of Fe and Pb between CuClbased flux and liquid copper at 1 473 K increased with adding Na 2 CO 3 , CaO or BaO to CuCl flux, and the concentrations of Fe and Pb in liquid copper largely decreased with time by using only CuCl flux. Mochida and Mikuni 11) also reported that the concentration of Fe, Pb, Zn or Sn in copper largely decreased with time by using Ar-10%Cl 2 gas mixture at 1 473 K, and the loss of Cu as CuCl was about 8 %.…”