Alkaline Sodium Glutamate System To Handle Low-grade Copper Oxide Ore

A new process of leaching copper oxide ore in the alkaline solution of sodium hydroxide containing monosodium glutamate has been investigated in view of the present situation of copper oxide ore in our country, which may supply a new method for metallurgistLeaching behaviors of basic cupric carbonate with monosodium glutamate were studied, and thermodynamics of Cu(Ⅱ) complex equilibrium in this system was studied by coordination chemistry fundamental. Varying the concentration of monosodium glutamate and pH value in the ranges of 0-3 mol/L and 5-14 respectively, the equilibrium thermodynamic diagrams were drawn, and the effects of monosodium glutamate concentration, pH value and free carbonate ion concentration on leaching of basic cupric carbonate were also studied. The comparison of theoretical calculation with experimental result shows that the absolute average value of relative error between them is 5.32%. From the results it is indicated that it is feasible to leach low grade cupric oxide ore with monosodium glutamate.The results of experiments about leaching the low grade cupric oxide ore from TangDan indicate that monosodium glutamate is a kind of feasible leaching reagents. The optimum conditions are as follows: concentration of monosodium glutamate 2mol/L, pH 9, temperature 80℃, reacting time 6 hours, ratio of liquid to solid 6:1. In the condition, the leaching rate of copper is 58.33%, while [Cu2+]T is 0.955g/L. Recycle leaching was carried out to increase the concentration of copper ion, which can only reach to 5.63 g/L after 10 times of being cycled.Adsorption thermodynamics and kinetics of copper(Ⅱ) on chelating resin D850 were studied to increase the concentration of copper ion in the leach liquor. The thermodynamic equilibrium functions of copper(Ⅱ) on chelating resin D850 in different temperatures determine AG<0, AH>0,△S>0, so the adsorption is spontaneous, endothermic and entropy increasing, which also indicates that chemisorption is the main process. Experimental data fitted well to the Langmuir model at all temperatures studied. And the decrease of free-energy and the increase of entropy are the driving force of copper(Ⅱ) on chelating resin D850. The kinetics results showed the process of ion adsorption is controlled by liquid film diffusion and particle diffusion. With the rising of concentration of OH-, adsorptive capacity of copper(II) on chelating resin D850 fell. When pH was 9 and concentration of copper(II) in solution was 14.45mmol/L, static adsorptive capacity of copper(II) on resin was 0.35mmol/g. Dynamic desorption results shows that 2 mol/L dilute sulphuric acid is a kind of good stripping agent of the loaded resin D850, and concentration of copper(II) in stripping solution can reach to 25g/L.