Recovery and Utilization of Lead in Lead–Containing Waste Residue from Electrolytic Manganese Production

Abstract

As a metallurgical and chemical raw material, electrolytic manganese is an important strategic resource. However, with the rapid development of the electrolytic manganese industry, the correct disposal of anode slime has become a serious problem. The purpose of this experiment was to reduce the occupation of land resources by the lead–containing waste residue of electrolytic manganese, reduce the pollution caused by the lead–containing waste residue to the environment and provide a reference for the research on the treatment technology and resource utilization of lead–containing waste residue in China. In this experiment, a special process was studied for the composition characteristics of lead–containing waste residues produced by electrolytic manganese. The acid leaching–enrichment–membrane electrolysis process was used to recover the lead in the lead–containing waste residues of electrolytic manganese and to recover the acid, so as to maximize the utilization of resources. In this experiment, the pretreated lead–containing waste residue was leached, enriched and concentrated, and then the enriched Pb2+ solution was used as cathode solution and dilute nitric acid as anode solution to recover lead by membrane electrolysis. The membrane electrolysis experiment uses lead plate as cathode, selects the best anion exchange membrane and anodic electrolysis material, and then takes lead recovery, acid recovery, current efficiency, voltage and power consumption as investigation indexes to explore and analyze the influence of many factors such as Pb2+ concentration and current density on the experiment, so as to determine the best membrane electrolysis process parameters. The optimum process parameters of lead recovery by membrane electrolysis were determined as follows: Pb2+ concentration was 40 g/L, current density was 30 mA/cm2, reaction temperature was 60 °C, cathodic pH value was 4.0, anodic HNO3 concentration was 0.5 mol/L, and cathodic ammonium nitrate concentration was 50 g/L. Under the optimal conditions, the current efficiency was 85.6%, the acid recovery was 73.03%, the lead recovery was 99.2%, the voltage was 3.8 V, and the power consumption was 1148.4 kW·h·t−1. Through the three steps of acid leaching–enrichment–membrane electrolysis, 78.53% of the Pb2+ in the original lead–containing waste residue can be recovered in the form of metal lead element, and the HNO3 recovered in the anode chamber can also be used again in the acid leaching process, which can not only solve the problem of environmental pollution caused by lead–containing waste residue but also achieve the recovery and utilization of resources, with good social and economic benefits.