Optimization-of-Electrolytic-Refining-Processes-Advanced-Monitoring-of-Liquids-with-ED-XRF-AR25.pdf

1、OPTIMIZATION OF ELECTROLYTIC REFINING PROCESSES:ADVANCED MONITORING OF LIQUIDS WITH ED-XRFBeatrice Biagioni AMETEK SPECTROPlatamone Patrick,Matteo Zavatta,Simone Marsan-ARGOR-HERAEUS SA 2THE ELECTROLITYC REFINING Anodic Reactions(oxidation):Ag Ag+e-E=-0,80 V Cu Cu2+2e-E=-0,341 V Pd Pd2+2e-E=-0,95 V

2、Pt Pt2+2e-E=-1,20 V Au Au3+3e-E=-1,498 V 2 Cl-Cl2+2e-E=-1,36 V Cathodic reaction(reduction):Au3+3e-Au E=1,498 V 3THE ELECTROLITYC REFINING Chemical reactions:3Ag(s)+4H+(aq)+3Cl-(aq)+NO3-(aq)3AgCl(s)+NO(g)+2H2O(l)3Cu(s)+8H+(aq)+6Cl-(aq)+2NO3(aq)3CuCl2(aq)+2NO(g)+4H2O(l)Au(s)+4H+(aq)+4Cl-(aq)+NO3-(aq)

3、AuCl4-(aq)+NO(g)+2H2O(l)3Pd(s)+8H+(aq)+12Cl-(aq)+2NO3-(aq)3PdCl42-(aq)+2NO(g)+4H2O(l)3Pt(s)+8H+(aq)+12Cl-(aq)+2NO3-(aq)3PdCl42-(aq)+2NO(g)+4H2O(l)The main influence in the success of the process,so in the quality of the final product,are:the optimization of the electric parameters the quality of the

4、 anode(generally from 700 to 990)the quality of the electrolytic solution4MONITORING OF THE ELECTROLYTIC SOLUTIONThe monitoring of the electrolytic solution is really important,sometimes is possible to choose the working plant depending on the quality of the anode,to increase the life of the solutio

5、n,so reduce the consumption of reagents of the solution and to make the process more constant in the quality.Is necessary to monitor the quantity of the contaminants as Pt,Pd and Cu,that can deposit on the cathode instead of gold and the quantity of the gold itself,to maintain a minimum quantity to

6、foster the deposit.Preparation of the electrolytic solution:Au(s)+4H+(aq)+4Cl-(aq)+NO3-(aq)AuCl4-(aq)+NO(g)+2H2O(l)5MONITORING METHODS FOR REFINING BATHS High precision:Accurate measurement of specific ion concentrations.Non-destructive:Does not alter the sample during analysis.Versatility:Can be us