Research On Microfluidic Extraction And Separation Of Copper, Iron And Zinc Ions

As a common metal,copper has been widely used in power electronics,light industry,construction,machinery,defense industry and other fields.With the rapid development of society and economy,China's demand for copper has increased rapidly,resulting in a shortage of high-grade copper resources in China.Therefore,effective treatment of low-grade copper ore and recovery of copper from secondary resources are significant for the stable development of the economy and society.In this work,the leaching solution containing low concentration copper is used as the research object.For the traditional process of solvent extraction and separation of copper and impurity elements such as iron and zinc,there are some problems such as long mass transfer distance,large consumption of extractant,easy emulsification and so on,research and development of new technologies for microfluidic solvent extraction of copper is presented.In this work,Y-type,T-type microchannel reactors and interdigitated microchannel reactor were applied to the traditional solvent extraction and separation of copper and iron,zinc.The effects of different parameters on the extraction and separation of copper and iron,zinc were revealed.The liquid-liquid two-phase flow patterns in the Y-type and T-type microchannel reactors were simulated,and the flow state of the organic phase and aqueous phase in the microchannel reactor was further revealed,which provided support for studying the extraction mechanism of the micro-channel reactor.The main research contents and conclusions are as follows:(1)Study on the extraction and separation of copper and iron,zinc in Y-type microchannel reactor.The results showed that the extraction rate of copper reached a maximum of 86.02%when the residence time was 0.783s.Compared with conventional extraction,it took at least 60 s to reach the same extraction rate.The separation coefficient of copper and iron and the separation coefficient of copper and zinc reached 465.53 and 1089.17,respectively,when the residence time was 0.783s in Y-type microchannel reactor.It was 5.4 times and 8.8 times the maximum value of conventional extraction.The overall volumetric mass transfer coefficient of copper in the Y-type microchannel reactor was 0.4937-3.3969 s-1.It is significantly higher than iron(0.0477-0.3173 s-1)and zinc(0.0395-0.2130 s-1).Compared with the overall volumetric mass transfer coefficient of copper in conventional extraction and Y-type microchannel reactors,it was found that the maximum of total volume mass transfer coefficient for copper increase 46.53 times.The results of stripping experiments showed that the copper stripping efficiency reached a maximum of 98.94%.(2)The extraction and separation of copper and iron,zinc in T-type microchannel reactor were crrried out.Under the optimal experimental parameters,the maximum extraction efficiency of copper reached 96.25%and the extraction rate of 0.29123 s-1 in the T-type microchannel reactor is significantly larger than the 0.11163 s-1 in conventional extraction.The maximum overall mass transfer coefficient of 0.772 s-1 in the T-type microchannel reactor is significantly larger than the 0.149 s-1 in conventional extraction.Numerical simulation of the pressure changes in the centerline of the microchannel indicated that the pressure drop in the T-type microchannel reactor was the Laplace pressure drop caused by the interfacial tension.The consistency of simulation and experimental for overall volumetric mass transfer coefficient results indicates the correctness of the model.(3)Study on extraction and separation of copper and iron,zinc in interdigitated microchannel reactor.The results showed that the extraction efficiency of copper was 84.05%when the contact time was 1.6×10-2 in the interdigitated microreactor,which is obviously better than the extraction efficiency of 77.72%in the conventional extraction of 60s.The separation factor copper/iron and copper/zinc(643.70 and 7416.69)were higher than 7 and 60 times of conventional extraction,respectively.Secondly,the extraction equilibrium isotherms of conventional extraction and interdigitated microreactor extraction were compared,it was found that the stages of extraction can be reduced in interdigitated microreactor.The value of overall volumetric mass transfer coefficients for copper in the interdigitated microreactor was increased by four orders of magnitude relative to conventional extraction.(4)Study on scale up and transplant of microfluidic solvent extraction.A microfluidic pilot extractor with a processing capacity of up to 60L/h was designed and manufactured.The effects of extraction of copper and extraction and separation of indium/iron were studied in the microfluidic pilot extractor.The results showed that the maximum extraction efficiency of copper was up to 99.5%,and the maximum extraction efficiency of indium was over 99%,and the separation coefficient of indium/iron was as high as 2727.47 in a microfluidic pilot extractor.In summary,compared with the conventional reactor,it has been found that the three kinds of microchannel reactor can achieve efficient separation of copper and impurity elements in a short period of time.Microfluidic solvent extraction technology will provide a new way for the high efficiency,integration and miniaturization of traditional solvent extraction technologies.