Extraction Of Gold And Platinum By Two-phase System Involving Nitrogen-containing Ionic Liquid

At present,the demand for precious metals represented by gold and platinum is gradually increasing in the industry,which puts forward higher requirements for the precious metal extraction field.In order to further optimize the precious metal extraction process,reduce the industrial pretreatment input,and develop a substitute for the traditional liquid-liquid extraction.In the new extraction process,three nitrogen-containing ionic liquids were synthesized in this paper,and the effects of salt effect,salt application and solid phase extraction were studied.Through the physicochemical properties of ionic liquid A336-P204 + inorganic salt system and the exploration of Pt(?)extraction,the influence mechanism of different ions and the influence law of each ion were found,and[HBBIm]Br-chloroform to Au(?)was attempted by inorganic salt ions to assist in stripping.Based on the problem of liquid-liquid extraction system ionic liquid loss and organic solvent pollution research,we will develop solid phase extraction system as the research focus,and focus on the preparation of solid phase extraction material and extraction effect test.The research of this paper mainly includes three section:(1)Exploring the physical property data of high-ion-rate systems in which inorganic salts participate in the construction and the mechanism and conditions for the extraction of platinum Pt(IV).It was first determined that[PtCl6]2-was achieved by anion exchange during the extraction process,[PtCl6]2-instead of[P204]-in the ionic liquid,and[A336]+ in a ratio of 2:1 Combines to form the extract[A336]2PtCl6.Under the optimal extraction conditions,the extraction rate of Pt(?)was nearly 99%.Subsequently,inorganic salt ions are separately added:sulfate ion,hydrogen phosphate ion and chloride ion.All three have no effect on the extraction process.However,bromide and nitrate ions have obvious inhibitory effects on the extraction of Pt(?)by A336-P204.For this phenomenon,we confirmed through the Hofmeister series that nitrate ions and bromide ions promote the hydration of A336-P204,making it easier to combine with water to form hydrogen bonds,making A336-P204 easy to dissolve into water.Unable to achieve extraction.In addition,we explain that the increase of ion rate will weaken the interaction between[A336]+ and[PtCl6]2-,which will also reduce the extraction rate of Pt(IV).This work predicted the ion effect of the Hofmeister sequence and further verified the mechanism of the ion-extraction system.(2)The effect of inorganic salt ions on the extraction of Au(?)by[HBBIm]Br-chloroform system was explored,and the application value of this effect was explored.We chose an imidazole ionic liquid[HBBIm]Br,which may be extracted by anion exchange,as an extractant,and studied its extraction conditions for gold Au(?)in[HBBIm]Br-chloroform liquid-liquid system,and verified us.Guess about its extraction mechanism.Then,we selected the same five common inorganic salts as in the previous part,and selected the most important one of the system,NaBr,by experiment.Finally,we tried the reverse extraction with NaBr and gradually converted the negative effects into positive influence.(3)The preparation of imidazole functionalized activated carbon material and its extraction of Au(?)under acidic conditions were realized.Based on the shortcomings of liquid-liquid extraction,we have tried to use an inexpensive and readily available activated carbon powder instead of an organic solvent as a carrier for ionic liquids to prepare an imidazole-based ionic liquid-modified functionalized activated carbon extraction material.The materials were used in the extraction of gold Au(?).Fourier transform infrared spectroscopy,Raman,elemental analysis and other analytical methods were used to characterize the material.At the same time,the nitrogen adsorption-desorption experiment was carried out to verify the structural stability of the material before and after treatment.The material has a maximum extraction rate of 98.8%for Au(?),and the anion exchange mechanism has also been verified.Considering that this extraction process can also be regarded as an adsorption process,we verified by experiments that the adsorption extraction of gold Au(?)by AC-[SiPMim]Cl is in accordance with the Langmuir isotherm adsorption model,which indicates that the extraction The adsorption process is a single layer adsorption and also indicates that the extractant is a single layer load on the surface of the activated carbon.In order to further study the extraction process of Au(?)from the functionalized materials,the thermodynamics and kinetics of the process were investigated.It was confirmed that the extraction process is an endothermic spontaneous reaction,which has certain reference value for the industrial application.