The Synthesis And Application Of Thioglycolic Acid Gold

With the development of the times,Gold-plated has been widely used in many respects in our daily life,such as computer circuit board,Gold-plated needle on CPU,mobile phone's touch keys,etc.Cyanide containing compounds is widely used in gold production because of its good stability,long service life,low cost.However,after the 12th five-year plan,China is facing the industrial transformation and upgrading,every manufacturing industries is pursuiting the goal that called environmental friendly and the saving resources development model,With the nature of toxic and wastewater its difficult to handled,cyanide compound plating system has severely breached the trend of social development.Therefore,more and more enterprises begin to develop a non-cyanogen gold coating system.Nowadays,Sulfurous acid salt and Citrate gold plating system are the most important system in non-cyanide system.Although Gold citrate toxicity descended distinctly,safer and more convenient than Potassium aurous cyanide,it still a cyanide containing compounds and can cause damage to the environment.And sulfurous acid salt with unstable plating bath,plating effect is not good.Therefore,non cyanide need a stable alternative to the gold cyanide.In this paper,the aim of the experiment is to synthesize a gold compound containing sulfhydryl ligands.And to characterize the the complexes,change it to a non-cyanide working fluid that suit to gold-plating.In this paper,the specific content of test can be classified as follow:(1)Aurous thioglycolic acid was synthesized for the first time and there is no Literature recorded.With the infrared analysis,ultraviolet detection and the gold content analysis,We can deduce the compound 's formulation.By the thermogravimetric analyzer we studied the compound 's thermal stability.And the optimal technological conditions synthesis of aurous thioglycolic acid was obtained through orthogonal experiment.(2)The solubility of aurous thioglycolic acid has been tested.And get the system that the production can be dissolved.(3)The thioglycolic acid potassium salt was synthesized,and the stability was tested.(4)By plating test and orthogonal test we obtained the optimum process conditions plating.(5)Explored the recovery rate of different gold waste liquid.The results of the test indicated:(1)With the infrared analysis,ultraviolet detection and the gold content analysis and compared with the theoretical value we deduced that the product's molecular formula is AuSCH2COOH.(2)pH=2,the mass concentration ration of thioglycolic acid-gold is 3:l,the temperature is 30? are the optimum technological conditions for the synthesis of thioglycolic acid gold.(3)Compound stability test showed that decomposition temperature is 208.11?.Insoluble in other organic acid and alkali liquid,can react with alkali solution to produce water soluble salts.Testd the stability of thioglycolic acid gold potassium salt solution,the results showed when the pH is greater than 7 the solution's chemical properties is stability,no precipitation,suitable for the non-cyanide plating reaction.(4)The storage conditions of Non cyanide gold complexes solution is pH 9-10 and shading preservation.(5)The optimum conditions for gold plating:glod 2g/L,Voltage 0.6V,temperature is 50? and pH is 9.Under these conditions,the coating color and binding force are excellent.(6)The rate of recovery of chloride acid gold waste water is 90%,the rate of recovery of thioglycolic acid gold waste water is 86%,the rate of recovery of thiourea gold is 89%.The rate of recovery of chloroauric acid gold waste liquid is greater than the other two kinds of organic ligand complexes.The recovery rate of gold is lower if the gold concentration is lower.Conclusion showed that we synthesized a kind of non cyanide ligand complexes that can be suitable for gold-plating.It is expected to become a kind of environmentally friendly products.