Research On 3D Printing Microfluidic Extraction Amplification Device And Its Extraction Performance

In the field of solvent extraction in hydrometallurgy,the common extraction equipment in industry,such as mixing clarifier,extraction tower,centrifugal extractor and so on,often have the problems of large area,long extraction reaction time,high consumption of extractant,and even potential safety hazards.In recent years,microfluid extraction technology has developed rapidly,and various microreactors have been used for solvent extraction.Take relevant scientific research in the field.The physical size of the effective channel or chamber of microreactor is reduced to micron level,which makes the gradient of physical quantities between fluids such as temperature,pressure,concentration and density increase sharply,which leads to a great increase of heat and mass transfer impetus,a few orders of magnitude increase of heat transfer coefficient and a few orders of magnitude decrease of mass transfer reaction time.Aiming at how to apply microfluidic technology to solvent extraction field better,a series of microfluidic extraction reactors were designed and manufactured by using 3D printing technology.The advantages of 3D printing were utilized to replicate and increase the mixing channels of microfluidic extraction reactors at very low cost.This method could not only inherit the advantages of high single-stage extraction efficiency of microfluidic extraction reactors,but also expand the capacity of microfluidic extraction reactor.In this paper,the related experiments of one single-channel microreactor?called Y-type single-channel microreactor?and three multi-channel microreactors?42-channel microreactor A and B,78-channel microreactor C,referred to as micro-reactor A,B and C respectively?are involved.In this paper,experiments were carried out on indium-iron system and platinum-palladium-rhodium system,which are difficult to separate and complex in solvent extraction industry.When the volume fraction of extractant P204 is 30%,the pH value of initial water phase is 0.7,and the contact time of oil-water two phases in mixed microchannels is 15 s,the extraction rate of In3+can reach 98.15%.At this time,the extraction rate of Fe3+is only 3.07%,and the separation coefficient of indium and iron is 1592.9,which is five times that of the conventional extraction method.Expanded experiments were carried out in microreactor A with mixed channels.It was found that the flow pattern of mixed fluids in microreactor changed from slug flow to trickle flow as the inlet flow rate increased to a certain extent?approximate flow rate V 21ml/min?.With the further increase of flow rate,the extraction rate of In3+increased because of the better mixing efficiency of trickle flow pattern,and the extraction rate of Fe3+increased because of the connection of trickle flow pattern.The contact time is too short and decreases,which makes the separation coefficient of indium and iron increase sharply with the increase of flow rate.For example,when the treatment capacity reaches 6L/h and the two-phase contact time is only 0.64s,the separation coefficient of indium and iron can reach 262.5.This phenomenon not only increases the extraction rate of In3+but also increases the treatment capacity of microreactor.In order to further expand the reaction and test the adaptability of microreactor to different systems,microreactors A,B which have 42 mixed-channel and microreactor C which has 78 mixed-channel were used to extract platinum,palladium from solution and separate rhodium.The results showed that the separation coefficient of?_Pt/Rh reached the maximum 104.8 and?Pd/Rh 127.9 when the flow rate was 192.5 ml/min,which exceeded45.7 and 65.3 levels of single-stage extraction in stirred tank of extraction workshop,respectively.When the flow rate was 210 ml/min,i.e.the treatment capacity was 12.6 L/h,the average contact time of two phases in the microreactor B and C was less than 1 s,and the platinum ion extraction rate could reach to 1 s.The extraction rate of palladium ion can reach about 80%with the increase of flow rate.The extraction rate of rhodium ion is only about 3%.The separation effect is better than that of stirred tank used in extraction workshop for 12 minutes.In summary,the design of microreactor by means of 3D printing and the application of microfluidic technology in the field of solvent extraction in metallurgy can play an important role in effectively shortening the reaction equilibrium time,reducing the cost of equipment manufacturing,increasing the capacity of Microreactor and improving the environment of solvent extraction in hydrometallurgy.As a new technology,microfluidic technology has great potential for development.It meets the basic requirements of basic research and development of advanced high precision,short flow and continuous Metallurgical new type reactor in the national medium and long term scientific and Technological Development plan.