Study On Hydrometallurgical Process For Treating Lead Anode Slime Bearing Bismuth And Kinetics Of Replace Bismuth By Sheet Iron

Abstract:Lead anode slime contains precious metals and other valuable metals such as bismuth,lead,antimony,copper and so on.Comprehensively recovery of all kinds of valuable metals is very important in the research of metallurgical process.A factory anode slime bearing high silver and bismuth, also containing Pb,Ag,Bi,Cu and Sb,needed to get crude bismuth and comprehensive recovery of valuable metals.Select hydrometallurgical process to treat the anode slime.The thesis sleet the process of Two stage leaching-hydrolysis-replacement of bismuth by iron" To recovery of Cu、Bi and Ag、Pb.The first of the process is leaching of copper with sulfuric acid and then leaching of bismuth with hydrochloric acid. lead and silver are enriched in the leaching slag. Studied on the relationship between the leaching rate and the leaching temperature, time, ratio of liquid to solid(Quality), dosage of acid and oxidant.Theleaching rate(Liquid) of copper is above96%,and The leaching rate(Slag) of bismuth and antimony are all above99%.The lead-silver slag containing Pb26.34%,Ag36.61%,the direct yield of Pb and Ag is high,are97.49%and99.24%respectively.The process is cycle leaching, washing water and washing acid are returned to the next leaching, which greatly reduced the amount of wastewater, and good for environmental protection.The powder copper is obtained by replacing of copper sulfate by iron powder,and the grade of sponge copper is66.92%,and the direct recovery of Cu is about95%.After replacement,the solution using limestone to precipitate Fe2+and SbO32-, then the pH of the solution is7,standards, and can be reused or discharged.The solution of Bi and Sb can be treeted by hydrolysis processing, using5mol/L ammonia to get to rid of Sb,through the analysis of Cl-and the concentration of metal ions in the solution, using a mathematical formulas to calculate the required amount of aqueous ammonia added.Themathematical model formula is The operating process is fine and high reliability,’which is superior to the traditional experience of operation.Then compared two different kinds of methods to get sponge bismuth powder,The first method is traditional iron powder replacement and the second method is replaced by sheet iron under micro-current.Using traditional process iron powder to replace sponge powder bismuth, the grade of bismuth powder is78.81%,and the direct yield of bismuth>95%.but the grade of bismuth is low.The grade of sponge powder bismuth is90%or more,which is replaced by sheet iron.The sheet iron as the anode and the graphite as the cathode,the current density is5×10-3A/cm2,the temperature is40℃.the waste water also using limestone to precipitate Fe2+and SbO32-, then the pH of the soLution is7, standards and can be reused or discharged.Electrochemical analysis showed that the role of micro-current promote replacement process,and the obtained sponge powder bismuth is high grade, fewer impurities, in particular, the lead content was significantly reduced.the replacement process studies have shown that, the replacement process meets one reaction rate law, activation energy Ea=13.72kJ/mol,and the reaction is diffusion-controlled.The reaction rate equation is...