| Using zinc-bearing dust sludge from a steel plant in Shanxi as raw material,through the synthesis of choline chloride-urea（Ch Cl-2Urea DES）and choline chloride-malonic acid（Ch Cl-MA DES）deep eutectic solvents.The experiments and kinetic study were carried out,which is of great significance for realizing the clean separation and efficient recovery of the dust sludge.The results of Laser particle size,etc.analysis of the dust sludge show that the average particle size is 47.86μm;zinc content is 12.98%,main zinc-bearing is zincite.The melting points of Ch Cl-2Urea DES and Ch Cl-MA DES are 13.0 and 14.5°C;the surface tensions at 25°C are 75.60 and 85.68 m N·m-1;the electrical conductivity is1.80 and 0.35 m S·cm-1.The viscosity and density of both decreased with the increase of temperature,and the former was more obvious.No new substances were formed in the two DESs,and the generation of hydrogen bonds was an important reason for the lowering of the melting point.The Ch Cl-2Urea DES leaching showed that the zinc leaching efficiency reached86.87%when 15:1,400 rpm,90°C and 600 min.The results of Ch Cl-MA DES showed zinc leaching efficiency reached 96.58%when 8:1,300 rpm,60°C and 120 min.The two leaching systems on the zinc leaching efficiency show that:the order of leaching factors for Ch Cl-2Urea DES is time>temperature>liquid-solid ratio>stirring rate;and Ch Cl-MA DES is temperature>liquid-solid ratio>time>stirring rate.The analysis and detection results of the leaching residue showed that most of the zinc in the residue was leached and other elements did not change significantly,which indicated that the two EDSs have special solubility for zinc,and the ability of Ch Cl-MA DES is stronger.The kinetic of dust sludge by Ch Cl-MA DES shows that the leaching of zinc conforms to the shrinking core model,the reaction is controlled by interfacial mass transfer and solid film diffusion,and the apparent activation energy is 35.92 k J·mol-1.Figure 48;Table 24;Reference 118... |
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