Research on microstructure of membrane-slime layer on lead-based anode surface in zinc hydrometallurgy by combining μ-XRF with mm-XRF

Abstract

In this paper, the synchrotron radiation μ-XRF and the mm-XRF method were used to emphatically study the composition, content and distribution of lead and manganese in anode slime on lead-based surface. The paper mainly explored the chemical features and the content evolution law of lead and manganese in the anode micro-zone of the anode surface, analyzed the corresponding relationship between the variation trend of lead and manganese contents and the thickness of micro-zone of the anode surface, scientifically determined the parameters of membrane preservation and slime removal by studying the quantitative layered structure of membrane-slime layer on the lead-based anode surface, and further verified the accuracy of the layered structure of membrane-slime layer through field slime removal experiment. The research results show that: (1) By using the respective advantages of μ-XRF and mm-XRF, and through in-situ study on the microstructure of anode slime by combining the two methods, it is revealed that there exists quantitative and fine layered structure of membrane-slime layer on the lead-based anode surface.(2) Through the research and analysis based on synchrotron radiation μ-XRF microprobe, the anode slime from the lead-based interface can be divided into membrane layer (high lead and dense), membrane-slime layer (intertwined high lead and low manganese and intertwined medium lead and high manganese) and slime layer (low lead and high manganese.(3) Further mm-XRF analysis of a large amount of data shows that the change rates of lead and manganese contents in anode slime from the lead-based interface vary significantly within the range of unit thickness; when the thickness is ＜1.0 mm, the lead content decreases most rapidly from 99% to 35%, and the lead content change value ΔPb is 64%/1 mm; when the thickness is 1.0–2.6 mm, the lead content change tends to be gentle, with a decrease from 35% to 10%, and ΔPb is 16%/1 mm; when the thickness is ＞2.6 mm, the lead content has no obvious change and fluctuates in a small range of about 10%. (4) Based on the above research, 2.6 mm on the lead-based surface can be determined as the limit thickness of anode membrane preservation and slime removal; the results of the membrane preservation and slime removal equipment developed on this basis show that compared with the manual slime removal results, the lead content of the anode surface after removing the slime by using membrane preservation and slime removal equipment drops from 80% to less than 10%.