Lithium Recovery From Geothermal Water With LMO By Electrochemical Method

In view of the lithium recovery from the low-concentration geothermal water in Tibet,a series of experiments on the electrode materials(LiMn2O4,LMO),the modification as well as the lithium recovery process from geothermal water have been studied systematically.The main conclusions are located in the following:(1)The effect of the source solution composition,recovery concentration and voltage as well as desorption/adsorption performance of the LMO-MO(λ-MnO2)electrode were investigated by electrochemical method.The optimal experimental conditions are:200 mg·L-1 Na+ solution as recovery solution and 0.8 V as desorption voltage.The desorption capacity of LMO graphite electrode can reach 27.16 mg·g-1 and the adsorption capacity can reach 11.80 mg·g-1.(2)In order to improve the performance of LMO electrode,electrode plate modification was investigated.① The LMO artificial wood porous electrode was successfully synthesized from resorcinol,formaldehyde and silica sol et al.The desorption experiment at 0.8 V was carried out.The results showed that the desorption capacity of the electrode was 5.56 mg·g-1,which is three times that of ordinary LMO graphite electrode with a poor adsorption capacity.② The effect of pore size and coating time on the desorption/adsorption performance of LMO-MO porous graphite electrode was investigated.The results showed that the desorption capacity of LMO porous graphite electrode decreases with the increase of coating time.With the increase of pore size,the delithiation quality of LMO porous graphite electrode is increased.The desorption performance of the 2 mm pore LMO graphite plate coated with three times is good,and the adsorption capacity reaches 28.17 mg·g-1.With the increase of coating times,the adsorption performance of MO porous graphite electrode shows a general attenuation trend,but the adsorption performance of the MO porous graphite electrode is greatly improved.The adsorption performance of the 1 mm pore MO graphite electrode coated with three times is the best,which is six times of the ordinary non-porous MO graphite electrode.(3)In order to improve the performance of the LMO electrode,the droped influence of Co,Cr and Zr in LMO material was investigated.LMO(blank,Co,Cr and Zr)powders were successfully synthesized with LiOH·H2O,MnCO3,Co2O3,Cr2O3 and ZrO2,and a series of characterizations were carried out.LMO(blank,Co,Cr and Zr)electrode plates were fabricated using ordinary graphite plates as carriers.Single desorption experiments on LMO(blank,Co,Cr and Zr)electrode plates at 0.8 V showed that metal doping reduced the desorption capacity of LMO electrode,but cyclic adsorption experiments showed that metal Zr can improve the cycle performance of the LMO electrode.