Extraction of Gold from Alkaline Gold Leaching Solution by Tertiary Amine N235 and Phosphine Oxide
Extraction of gold from alkaline gold leaching solution by N235-TRPO synergistic system was studied. The effects of the concentrations of Tri-akylphosphine oxide(TRPO)and tertiary amine(N235), the initial pH, and the concentration of gold on the extraction of gold and the extraction isotherm were inspected. The ability of extracting other metal elements by this system had been investigated. The effect of alkali concentration on stripping of gold from loaded organic phase had also been studied. The experimental results indicate that the system consisting of 10% N235, 10% TRPO gave high extraction yield for gold along with the lesser extraction of silver and copper which are needed to recover. The gold extraction was over 94%, at pH=9~10 and the stripping of gold from loaded organic phase using 0.05mol/L NaOH can reach91.43%.
Study of the extraction of gold(III) in aqueous hydrochloric acid media by the phosphine oxide Cyanex 925
Abstract The extraction of gold(III) from hydrochloric acid solutions by means of the phosphine oxide Cyanex 925 was studied as a function of different variables: equilibration time, temperature, organic diluent, and concentration of gold, Cyanex 925, HCl, etc.; the system is selective with respect to the extraction of a number of metals. Gold(III) equilibrium loading isotherms were also obtained at 20°C. Experimental data were treated numerically showing that gold extraction can be explained assuming the formation of a complex with the general stoichiometry: HAuCl 4 L 2 , where L represents the extractant. For the extraction reaction log K ext o = 8.1. The stripping of gold from loaded organic phases can be achieved with water. Data on the extraction of HCl by Cyanex 925 are also presented.
Atmospheric drag effects on the KOMPSAT-1 satellite during geomagnetic superstorms
We examine the atmospheric drag on the low earth-orbiting satellite, KOMPSAT-1 in a sun-synchronous orbit at ~685-km altitude starting in 1999, during a 3-month (October-December) period in 2003. This 3-month interval includes the October 29-30 and November 20 magnetic superstorms and weak to moderate storms. We observed that the daily KOMPSAT-1 drag acceleration transiently responses to transient storm-time disturbances. That is, there is an one-to-one correspondence between the KOMPSAT-1 drag accelerations and the storm events. We find that the drag acceleration correlates strongly with the level of geomagnetic disturbance. This indicates that the trajectory of KOMPSAT-1 is significantly perturbed during extremely disturbed intervals because of atmospheric density increase. The main contributor to the density increase is Joule heating associated with the geomagnetic activity rather than the solar EUV radiation, as reported by previous studies. We suggest that understanding how the upper atmosphere responses to the geomagnetic-associated heating is important to predict space weather impacts on low earth-orbiting satellites.