Process Of Zinc Recovery From The Waste Anti-corrosion Coatings

As the increasingly shortage of Zinc resources, the recycling of the secondary resource become an important topic in the world. At present,the anti-corrosion coatings use widely, which will produce lots of abandoned paint. The abandoned paints contain a large number of Zinc, which not only cause serious harm to the ecological environment and human health when it place improperly, but also cause the lossing of the secondary resources. The abandoned paints are the important secondary resources of metal recycling, which will play a significant role in the country's sustainable development when people change them into harmless resources. At present, the study of recycling of secondary resources has become a hot topic in metallurgical industry.Taking the abandoned paint as the materials, the process metallurgy as the basis, combine with the property of the materials, the paper offer a technology of "acid leaching—extraction—electrolysis" to recycle the Zinc from the abandoned paint. The paper also make a systematicly research on the related basic theories about the technology. The technology has many advantages such as short process flows, less equipment investment, low energy consumption, less pollution, environmental friendly and high metal recycling. The process flows assess the feasibility of technology.Based on the experimental study, the paper offer the leaching technology, choose the best leaching agent and discuss the influence of the liquid-solid ratio, leaching time, leaching temperature, leaching agent concentration. The particular conditions are as follows: vitriol concentration 2mol/L, leaching time 2h, leaching temperature 25℃, liquid-solid ratio 15:1. The leading ratio of the Zinc can reach 62.36%.Based on leaching process, the experiment get Zinc from zinc leaching solution which take P204 as the extractant, 260 kerosene as diluent agent. During the research in experiment, the paper discuss some factors of pH value of aqueous phase, extraction time, organic phase composition, oil-water ratio, from which get the optimum extraction conditions. The specific conditions are as follows: aqueous phase pH value 4 , organic phase composition 20% P204 +80% kerosene, oil-water ratio 1:1, extraction time 15min. The extraction raito of Zinc can reach 45.49% in the optimum condition. The paper can get zinc sulfate solution accord with the electrolytic zinc during the process in extraction and back-extraction.