Research On Migration Behavior Of Lead In Electrolytic Manganese Anode Slime

In the production of electrolytic manganese,it produced a kind of anode slime that contain lead,which main composition is electrolytic manganese dioxide and lead at the anode area.This research focused on the migration behavior of lead in the electrolytic manganese anode slime pretreated by grinding,washing and roasting and leached by complex acetic acid ammonium to explore the influence of factors in the leaching system on the leaching rate of lead,and made a series of research on migration regularity and explored the recycling process of lead ion in the leaching solution.The main experimental results are as follows.Firsty,This study used XRF and FAAS to analyze element content in anode slime roasted at 750 ? and 950 ? in nitrogen atmosphere and air atmosphere.The results showed that the anode slime mainly had Mn,Pb,Ca,Se,Sr and some other elements,manganese content was 47% on average,lead was 7.55% on average.From the comparative analysis of TG-DTA analysis under air atmosphere and nitrogen atmosphere,the temperature node of the transformation of MnO₂ to Mn₂O₃ in nitrogen atmosphere was less than 50 ? to the air atmosphere,and time node was less than 5 min,the main material of the anode slime in nitrogen atmosphere under roasting temperature in 750 ?was Mn₂O₃.SEM-EDS analysis to the anode slime under roasting temperature in 750 ?and 950 ?,indicated that the anode slime under roasting temperature in 750 ? formed a ball system,connected into mesh.the anode slime under roasting temperature in 950 ?formed a typical colloidal system,existing as a kind of dense "mineral" phase,it is harder to edulcoration.EDS analysis showed that the main material is manganese oxide and Pb is the mainly impurity.This paper respectively discussesed the influence of roasting temperature,types of leaching agent,leaching agent concentration,leaching time,liquid-solid ratio and leaching temperature to migration electrolytic of lead ion of electrolytic manganese anode slime.The experimental results showed that the anode slime in nitrogen atmosphere under roasting temperature in 750 ?was beneficial to the leaching of lead ion,the migration rate of lead ion in the leaching liquid NH₄Ac was faster than HAc,Na Ac under the action of the NH₄⁺,the contacting opportunities between the Pb²⁺ in anode slime particle and Ac-in leaching liquid was increased when the concentration of NH₄Ac was 2mol/L,and increase the efficiency of the migration of lead,and the optimum leaching time was 0.5 h,liquid-solid ratio is 8:1;the leaching temperature promoted the leaching rate of lead ion,and the migration behavior of lead ion conformed to the linear rule y=ke-a E-0bx,k is leaching reaction rate and increased with the increase of temperature.Changed the initial concentration of lead ion in the leaching liquid under the optimum process conditions,it presented a negative impact between the initial concentration of lead ion and lead ion migration.According to the preliminary experimental results infered the mechanism model of the migration of lead in electrolytic manganese anode slime after pretreatment: Firsty,leaching agent permeate to the inside of electrolytic manganese anode slime and made electrolytic manganese anode slime wetting;Secondly,the lead combined with leaching agent;Thirdly,the diffusion of the lead from internal impurities to the surface of electrolytic manganese anode slime and from the surface of electrolytic manganese anode slime to the body of leaching liquid.And explored out that the temperature was higher,the the rate of the leaching of lead ion was faster and the K was the greater.From the wholeprocess to remove the impurity of the anode slime that migration routes have three types:10% of the total was transferred from the surface of the anode slime particle,85% of the total was transferred from the internal crack of the anode slime particle,5% of the total was transferred from lattice of the manganese oxide of the anode slime.Finally,this research explored the recycling process of lead ion in the leaching liquid.Quantitative drop 98% sulfuric acid into the leach liquor when the lead ion concentration was biger than or equal to 0.005mol/L,the lead recovery rate is 99%.Used the cation exchange resin method to enrich the lead of the leach liquor when the lead ion concentration was litter than 0.005mol/L,the rate of the enrichment is 99%,droped 98%sulfuric acid into the eluent of the cation exchange resin to recover the lead sulfate.