The Resoure Utilization Of Fly Ash-Resin Extract Gallium And Desodium Of Red Mud By Lime Method

In the earth’s crust, the content of Gallium(Ga) is about1.5×10-3%, it is thewidely used but rarely raw metal elements. In the process of fly ash extract Al2O3withthe method of alkali lime sintering, about70%of Ga into sodium aluminate solutionalong with Al, so it has great value of extraction.In this experiment, simulate containing Ga extract liquor solution first, which inthe process of fly ash extract Al2O3with the method of alkali lime sintering, namelythe sodium aluminate solution. And then adsorb the simulation Ga solution with XRresin which containing amidoxime group. And some influence factors of the process,such as different temperature, time, stirring speed and other conditions are analyzedtheoretically to determine the optimum conditions of adsorption, meanwhile, theadsorption thermodynamics and adsorption kinetics of the resins are analyzedtheoretically, too. Then focus attention to the difficult desorption problem of saturatedresin, using different desorption solution on saturated resin elution to select the bestone and seeking the best desorption conditions, and using Fourier transform infraredspectrometer to probe the mechanism of absorption and desorption. Finally, extractingGa from the industrial sodium aluminate solution with above experimental data.(Thesodium aluminate solution is obtained from the CPI Shanxi Aluminum Co. Ltd. in thisexperiment)The optimal conditions of extracting of Ga are as follows: adsorption temperatureis15℃, adsorption time is50mim, stirring speed is300r·min-1, in the above conditions,the equilibrium adsorption resin on the simulation solution of Ga is up to15.7mg.g-1.The thermodynamic properties of extracting according with Langmuir isothermalequation, and the Lagergren pseudo-second order kinetic model gave a good correlation for the adsorption of Ga. The optimum desorption solution is the compoundsolution of NaOH and Na2S, the optimum desorption conditions are as follows:desorption concentration3mol·L-1NaOH and0.9mol·L-1Na2S; desorption temperatureis30℃desorption solution flow rate is10mL·h-1. FTIR spectroscopy results show thatamidoxime in the resin involved in the coordination reaction with GaO2-, because boththe amine and the oxime have residual arc on the electron pair, which can be chelationreacted with GaO2-. By extracted three times, the Ga concentration in desorptionsolution was1009.3mg·L-1, has reached the lowest Ga electrolytic concentration(1g·L-1), which can be directly electrolysed after further depurating to obtain thefinished Ga. Extracting Ga from sodium aluminate solution with this method is noneed to add anything, and no effect on the fly ash extract the main process of Al2O3.The red mud is solid waste discharg which from the process of fly ash extractAl2O3with the method of alkali lime sintering. The large number of fly ash red muddischarge has severely limited the development of the fly ash-aluminum-mentionindustry. So reusing fly ash red mud effectively can reduce pollution and turn wasteinto treasure.The experimental results show that main factors of desodium are: temperature>liquid-solid ratio> reaction time>([CaO]/[Na2O]). The optimum reaction conditions ofred mud desodium with single factor experiment and orthogonal experiment are asfollows: reaction time is130min, reaction temperature is90℃, liquid-solid ratio is6,[CaO]/[Na2O] is6, in this condition, the desodium rate is56.87%, sodium content infly ash red mud (Na2O, the same below) is from1.61%to0.46%, has reached theexpected1%, can be used to produce the Portland cement clinker, which is a lot ofdigestion.