Study On Analysis Of The Trace Organophosphorous Extractants In Nickel Electrolyte

In hydrometallurgy,the organophosphorous extractants such as Cyanex272,P204 and P507 are the common acidic extractants for the separation of cobalt and nickel.Above of acidic extractants with strong polar,strong chelate power with metallic ion and largo water solubility are the main residual organic components in electrolyte.These residual organic compounds could be accumulated in electrobath and will make a strong impact on current efficiency and the nucleus formation of nickel in nickel electroanalysis process.As a result, there are some blowholes leaving on nickel sheet surface and decreases possessive ratio of market,moreover,results in waste in energy and resources.So it is very important to develop the qualitative and quantitative analysis methods for the residual organic components in electrolyte to resolve the above problem.In addition,the developed methods also can be used to investigate the variety and concentration level of organic components in electrolyte to find the influence factors to the appearance quality of products.Therefore,it is also significant to improve the use efficiency in resources and energy.This study focuses on the methods development of organophosphorous extractants analysis in nickel electrolyte including sample precontration methods and GC analysis methods.In organophosphorous extractants analysis,liquid-liquid extraction(LLE) combined gas chromatography analysis was mainly used at present.But the LLE has many disadvantages such as tedious operation,small concentrated multiple,using more organic solvent,causing environmental pollution and harming human health etc.Compared with conventional LLE,solid phase extraction(SPE) offers some advantages including cleaner extract,less solvent handing,lower manual labar,easy be automated etc,therefore this paper used SPE to preconcentrate the organophosphorous extractants from electrolyte.In addition, the conditions of silylation reaction were optimized in the derivative analysis of gas chromatography to improve the accuracy of the analytical method.There are six chapters in this dissertation:Chapter 1:Firstly,the background and significance of paper were set forth;Secondly,the analytical methods of organophosphorous extractants in nickel electrolyte were reviewed; Finally,the ideas and contents of study were outlined.Chapter 2:The principles,operation,application domain of SPE and the derivative anal),tical methods of gas chromatography were reviewed.Chapter 3:The purification and purity identification of industrial organophosphorous extractants were studied because of standards lack.The industrial Cyanex272 was purified through the method of cupric salt crystallization and the 99.2%purity of bis-(2,4, 4-trimethylpentyl) phosphinic acid(BTMPPA) was obtained.In addition,the purity of industrial Cyanex272,P204,P507 and BTMPPA,were determined by potentiometric titrations and the results were 86.27%,97.38%,93.23%,99.2%,respectively.Chapter 4:In this study,the qualitative and quantitative derivative analytical methods of gas chromatography for the analysis of organophosphorous extractants were established and silylation was adopted to reduce the boiling points of organophosphorous extractants, meanwhile,the silylation condition was optimized.In addition,the influence of excess derivatising agents was investigated and eliminated.Chapter 5:The SPE was firstly applied to the enrichment of organophosphorous extractants from nickel electrolyte.Two kind of pretreatment methods,one is enriching BTMPPPA from nickel electrolyte of undissolved anode technics and other is enriching P204 and P507 from nickel electrolyte of dissolved anode technics were established.The study results show that ENVI-18 cartridge has a good adsorption effects to organophosphorous extraetants in three kinds of tested absorbents.Moreover,the orthogonal test design was used to optimize the SPE operation condition.The SPE recoveries of BTMPPA,P204 and P507 were 68.80%,68.14%, 73.10%respectively and the relative standard deviations(RSD) were between 4.8%and 10.22 %,which indicate that the accuracy and precision of SPE were satisfactory.Chapter 6:Conclusion,innovation,shortage and suggestions.In this paper,the SPE was successfully applied to the pretreatment of organophosphorous extraetants from nickel electrolyte and a good accuracy and precision were obtained to satisfy the need of trace analysis.Furthermore,the derivative analytical methods of gas chromatography for the analysis of ganophosphorous extractants in nickel electrolyte of undissolved and dissolved anode technics were established,respectively.In addition,the purification and purity identification of industrial organophosphorous extractants were also studied to overeom,e the lack of standards.The developed off-line SPE methods will be a useful instruction for the on-line SPE operation.