1. Exp. # Chlorinating agent, i Mass of chlorinating agent i, w i / g Amount of element in the chlorinating agent j, M j / mol CuCl aCuCl 2 4.0280.030.06 bCuCl 2 5.9440.06 CuCl ( l ) PtCu ( s ) 0 -30 -20 -10 0 -30 -20 -10 -20 -10 log p Cl 2 log a Pt log a Cu PtCl 2 Cu-Pt-Cl system T = 873 K Pt ( s ) Cl 2 ( g ) Cu ( s ) New Separation and Recovery Process of Platinum Using Chlorinating Agents Chiyoko Horike and Toru H. Okabe* Graduate Student, Graduate School of Engineering, The University of Tokyo; *Institute of Industrial Science, The University of Tokyo, Introduction (Global scale, 2006) Typical recovery process Thermodynamic analysis Results and DiscussionConclusion Purpose of this study Development of a new process for an effective recovery of PGMs from scrap Mg － Pt compounds and Pt were reacted with a chlorinating agent (CuCl 2 or CuCl) at 873 K for 3 h. XRD analysis ・ Cl can be supplied by dissociation of chloride salts. ・ Mg can be chlorinated faster than Pt. ・ CuCl 2 is dissociated into Cl 2 and CuCl around 873 K. ・ Vapor pressure of CuCl is lower than 10 -4 atm. Experimental Demand & Supply Chlorination apparatus Synthesis of Mg － Pt compounds Stainless steel reaction vessel Ta crucible Pt plate Stainless steel plate Ti sponge TIG welding Stainless steel cover Mg block Pure Pt was reacted with molten Mg at 1173 K for 12 h. → Homogeneous Mg － Pt compounds were formed. (SEM, EDS, XRD) ① Compound formation under a highly reducing atmosphere → Pretreatment for selective and efficient dissolution of PGMs ② Chlorination → High dissolution efficiency → Smaller amounts of acids required for dissolution → Fast dissolution Chemical potential of chlorine ③ [PtCl 6 ] 2– Oxidation/Dissolution ② PtCl x Chlorination ① R － Pt ( R: reactive metal) p Cl 2 Pt t process Short dissolution time South Africa ： 165 t (69%) Automotive catalyst ： 131 t (55%) Russia ： 27 t (11%) North America ： 11 t (4%) Other Recovery from automotive catalyst ： 27 t (11%) Chemical ： 11 t (5%) Electrical ： 13 t (6%) Jewelry ： 50 t (21%) Other (a) Demand of Pt : 239 t(b) Supply of Pt : 240 t Mass of platinum, w Pt / t Demand Recovery Estimate Year World demand and recovery for Pt Waste solution Residue Scraps containing PGMs (M) Mg vapor treatment Mg － M compounds Chlorination MCl x Dissolution Solution containing PGMs PGMs recovery Pure PGMs Reactive metal (R) (R: Mg) Chlorinating agent (CuCl x ) (X = 1, 2) HCl aq. (M: Pt, etc.) This study Flowchart of the new process Vapor pressure of selected metals and chlorides Ellingham diagram Reciprocal temperature, 1000 T -1 / K -1 Vapor pressure, log p i (atm) Pt Cu CuCl FeCl 3 Mg 873 K673 K FeCl 2 MgCl 2 MgCl 2 ・ 6H 2 O # 25-0515 CuCl# 06-0344 Pt# 04-0802 1 cm Intensity, I (a.u.) Angle 2θ / degree Exp. # (a) Chlorination by CuCl 2 for Mg － Pt Exp. # (b) Chlorination by CuCl for Mg － Pt Intensity, I (a.u.) 1 cm Angle 2θ / degree Exp. #sample Chlorinating agent, i Composition of element k, C k (mass%)* MgPtCuCl － Mg － Pt － 13.667.000.0 － a Chlorinated Mg － Pt CuCl 2 10.747.604.8Bal. b Chlorinated Mg － Pt CuCl 2 07.136.117.0Bal. Composition analysis * Determined by ICP-AES analysis. The amount of Pt with an oxidation state of two was determined by calculation. Exp. # (a) 20%Pt Exp. # (b) 78%Pt Pt can form complex compounds. Standard Gibbs energy of formation, ΔG f ゜ / kJ ・ (mol ・ Cl 2 ) -1 Temperature, T / K PtCl 3 PtCl 2 CuCl 2 FeCl 3 FeCl 2 CuCl MgCl 2 673 K873 K ・ Reaction temperature was determined at 873 K. ・ CuCl 2 and CuCl were selected for the chlorinating agent. Potential diagram Weight measurement Ratio of weight, R Comparison of weight change Ratio of weight, R = w o,i / w f,i w f,i : Weight of the feed samples w o,i : Weight of the obtained samples Mg alloying of Pt was clearly effective for the reaction with CuCl x (x = 1, 2). Mg － Pt Pt Mg － Pt Pt Exp. # (a) CuCl 2 Exp. # (b) CuCl 0.403 g0.399 g0.398 g0.401 g0.628 g0.398 g0.751 g0.475 g Chlorination condition Pyrometallurgical process ○ High efficiency & speed × High energy cost & large facilities Hydrometallurgical process ○ Low energy cost & easy handling × Long processing time & generation of a large amount of waste solution Cu 3 Pt# 35-1358 A fundamental technique that utilizes the selective alloying of PGMs with collector metals followed by chlorination/oxidation was studied. ・ Mg － Pt compounds and Pt were chlorinated by using a chlorinating agent (CuCl 2 or CuCl) at 873 K for 3 h. ・ Mg alloying of Pt was clearly effective for the reaction with CuCl x (x = 1, 2). ・ After chlorination for Mg － Pt by CuCl 2, MgCl 2 and pure Pt were formed, and the obtained sample was contaminated by CuCl. ・ After chlorination for Mg － Pt by CuCl, Cu 3 Pt was formed. ・ Development of new supplying method of CuCl x (x = 1, 2) for more effective chlorination of Pt. ・ Integration of the proposed chlorination method with the conventional dissolution methods in order to investigate practical processes. Future work vacuum Quartz tube Heater Glass woolQuartz crucible Powder of Mg － Pt Pt powder Chlorination agent (CuCl 2 or CuCl) 873 K Temperature, T / K Scrap containing precious metals (M) Pretreatment (Crushing, etc.) Cu, Pb, Fe, etc. Extraction by collector metals Collector metal containing M Dissolution in acid Separation and purification Recovered precious metals Directly dissolved in acid Pyrometallurgical process Hydrometallurgical process