Deselenization of caustic solution with high alkalinity by synthetic Ca-Al-Cl-LDHs
In industrial production,copper anode slime is the main raw material for selenium extraction.Alkali metallurgy is an effective method and an important development direction for the treatment of anode slime.The bottleneck of large-scale treatment is the effective separation and enrichment of selenium in strong alkaline leaching solution.To extract the selenium in the caustic leachate with high alkalinity,this study synthesized the Ca-Al-Cl layered double hydroxides(Ca-Al-Cl-LDHs)with a formula of Ca2Al(OH)6Cl·2H2O by three different co-precipitation sequences of the CaCl2 and AlCl3 solution in the NaOH solution.A plate-like and fine crystal morphology was observed by the scanning electron microscope.The X-ray diffraction spectra and Fouriertransform infrared spectra further confirmed a layered double hydroxide structure of hexagonal crystal with the typical mineral phases and functional groups.The forward feeding samples exhibited the best adsorption capacity of Se(Ⅵ).The factor experiments concerning diverse adsorption temperatures,adsorbent dosages and alkali concentrations then revealed a favorable adsorption process with low temperatures,low NaOH concentration and high adsorbent dosage,where a significant desorption by the decomposition of LDHs at above 70℃ was also observed.The pseudo-second-order kinetic was better fitted and the adsorption isotherm found that the maximum adsorption amount(qm)of Se(Ⅵ)of Ca-Al-Cl-LDH at 50℃reached 248.18 mg g-1.These results suggest the Ca-Al-Cl-LDH can act as a promising adsorbent for highly efficient deselenization.
Copper anode slime Coprecipitation Ca-Al-Cl-LDHs Selenium adsorption
Shaodong Xu Dong Li Xueyi Guo
School of Metallurgy and Environment,Central South University,Changsha 410083,China
国内会议
厦门
英文
78-87
2019-04-24（万方平台首次上网日期，不代表论文的发表时间）