ﻣﻄﺎﻟﻌﻪ ﺗﺎﺛﯿﺮ ﯾﻮن ﻓﺮﯾﮏ و ﭘﯿﺮﯾﺖ ﺑﺮ واﮐﻨﺶ اﮐﺴﯿﺪاﺳﯿﻮن ـ اﺣﯿﺎ ﺳﻄﺢ ﮐﺎﻟﮑﻮﭘﯿﺮﯾﺖ ﺑﺎ اﺳﺘﻔﺎده از ﺗﮑﻨﯿﮏﻫﺎي اﻟﮑﺘﺮوﺷﯿﻤﯽ و ﻣﺤﺎﺳﺒﺎت ﺗﺮﻣﻮدﯾﻨﺎﻣﯿﮑﯽ

Ferric ion and pyrite effect on the oxidation-reduction reaction of chalcopyrite surface using electrochemical techniques and thermodynamic calculations

اﻧﺤﻼل اﺳﯿﺪي ﮐﺎﻟﮑﻮﭘﯿﺮﯾﺖ در ﺣﻀﻮر ﯾﻮن ﻓﺮﯾﮏ ﯾﮏ ﭼﺎﻟﺶ ﻋﻠﻤﯽ اﺳﺖ ﮐﻪ ﻣﻮﺿﻮع ﺗﺤﻘﯿﻖ ﺑﺴﯿﺎري از ﻣﺤﻘﻘﺎن ﻣﯽﺑﺎﺷﺪ. ﻧﻘﺶ ﭘﯿﺮﯾﺖ ﻧﯿﺰ ﺑﻪ ﻋﻨﻮان ﯾﮏ ﺷﺘﺎبدﻫﻨﺪه )ﮐﺎﺗﺎﻟﯿﺴﺖ( و اﻓﺰاﯾﺶدﻫﻨﺪه اﻧﺤﻼل ﮐﺎﻟﮑﻮﭘﯿﺮﯾﺖ ﻣﻮرد ﺑﺮرﺳﯽ ﻗﺮار ﮔﺮﻓﺘﻪ اﺳﺖ. ﻣﻄﺎﻟﻌﺎت ﮔﺬﺷﺘﻪ ﺑﯿﺎﻧﮕﺮ اﻧﺤﻼل اﻟﮑﺘﺮوﺷﯿﻤﯽ ﮐﺎﻟﮑﻮﭘﯿﺮﯾـﺖ در ﺣﻀﻮر اﮐﺴﻨﺪهﻫﺎﺳﺖ و واﮐﻨﺶﻫﺎي اﮐﺴﯿﺪاﺳﯿﻮن - اﺣﯿﺎ ﺑﻪ ﺷﺮاﯾﻂ ﻣﺤﯿﻂ واﮐﻨﺶ واﺑﺴﺘﻪ اﺳﺖ. در اﯾﻦ ﻣﻘﺎﻟﻪ ﻋـﻼوه ﺑـﺮ ﺗﮑﻨﯿـﮏﻫـﺎي اﻟﮑﺘﺮوﺷـﯿﻤﯽ وﻟﺘﺎﻣﺘﺮي ﭼﺮﺧﻪاي و ﮐﺮوﻧﻮآﻣﭙﺮوﻣﺘﺮي( از ﻣﺤﺎﺳﺒﺎت رﯾﺎﺿﯽ و ﻣﻌﺎدﻻت ﺗﺮﻣﻮدﯾﻨﺎﻣﯿﮑﯽ ﺟﻬﺖ ﺑﺮرﺳـﯽ اﺛـﺮ ﯾـﻮن ﻓﺮﯾـﮏ و ﭘﯿﺮﯾـﺖ ﺑـﺮ واﮐـﻨﺶﻫـﺎي اﮐﺴﯿﺪاﺳﯿﻮن اﺣﯿﺎ ﺳﻄﺢ ﮐﺎﻟﮑﻮﭘﯿﺮﯾﺖ اﺳﺘﻔﺎده ﺷﺪه اﺳﺖ. اﺑﺘﺪا واﮐﻨﺶﻫﺎي اﮐﺴﯿﺪاﺳﯿﻮن اﺣﯿﺎ ﺳﻄﺢ ﮐﺎﻟﮑﻮﭘﯿﺮﯾـﺖ ﺑـﺎ روش وﻟﺘـﺎﻣﺘﺮي ﭼﺮﺧـﻪاي در ﻣﺤﯿﻂ اﺳﯿﺪي و ﺳﭙﺲ اﺛﺮ اﻓﺰودن ﯾﻮن ﻓﺮﯾﮏ ﺑﺮ اﯾﻦ واﮐﻨﺶﻫﺎ ﺑﺮرﺳﯽ ﻣﯽﺷﻮﻧﺪ. در اداﻣﻪ اﺛﺮ ﺣﻀﻮر ﭘﯿﺮﯾﺖ ﺑﺎ اﺳﺘﻔﺎده از اﻟﮑﺘﺮودﻫﺎي ﺗﺮﮐﯿﺒـﯽ ﭘﯿﺮﯾـﺖ/ ﮐﺎﻟﮑﻮﭘﯿﺮﯾﺖ، در ﮐﻨﺎر ﯾﻮن ﻓﺮﯾﮏ ﺑﺎ روش ﻣﺬﮐﻮر ﻣﻮرد ﻣﻄﺎﻟﻌﻪ ﻗﺮار ﮔﺮﻓﺖ. ﻧﺘﺎﯾﺞ روشﻫﺎي وﻟﺘﺎﻣﺘﺮي ﭼﺮﺧﻪاي ﻧﺸﺎن داد ﮐﻪ ﯾﻮن ﻓﺮﯾﮏ و ﭘﯿﺮﯾﺖ ﺷﺪت ﭘﯿﮏﻫﺎي آﻧﺪي و ﮐﺎﺗﺪي را اﻓﺰاﯾﺶ ﻣﯽدﻫﻨﺪ و اﺛﺮ ﻣﺜﺒﺘﯽ ﺑﺮ واﮐﻨﺶﻫﺎي ﺳﻄﺢ ﮐﺎﻟﮑﻮﭘﯿﺮﯾﺖ دارﻧﺪ. ﭘﯿﺮﯾﺖ ﺑﻪ ﻋﻨﻮان ﮐﺎﺗﺎﻟﯿﺴﺖ ﺷـﺮاﯾﻂ را ﺑـﺮاي ﺗﺴـﺮﯾﻊ ﮐﺎﻫﺶ ﯾﻮن ﻓﺮﯾﮏ در ﺳﻄﺢ اﻟﮑﺘﺮود را اﻓﺰاﯾﺶ ﻣﯽدﻫﺪ. ﻫﻤﭽﻨﯿﻦ ﻧﺘﺎﯾﺞ روش ﮐﺮوﻧﻮآﻣﭙﺮوﻣﺘﺮي و ﻣﻄﺎﻟﻌﺎت ﺗﺮﻣﻮدﯾﻨـﺎﻣﯿﮑﯽ ﺑﯿـﺎﻧﮕﺮ اﻓـﺰاﯾﺶ اﻧـﺮژي آزاد واﮐﻨﺶ اﮐﺴﯿﺪاﺳﯿﻮن ﮐﺎﻟﮑﻮﭘﯿﺮﯾﺖ در ﺣﻀﻮر ﭘﯿﺮﯾﺖ ﺑﻮد ﮐﻪ ﻣﻘﺪار آن ﺑﺮاﺑﺮ ﺑﺎ22/45 - ﮐﯿﻠﻮژول ﺑﺮﻣﻮل ﻣﯽﺑﺎﺷﺪ.

Acidic dissolution of chalcopyrite in the presence of ferric ion is a scientific challenge that is the subject of research by many researchers. The role of pyrite has also been studied as catalyst and enhancer of chalcopyrite leaching. Previous studies have shown the chalcopyrite electrochemical leaching in the presence of oxidants, and oxidation-reduction reactions depend on reaction environmental conditions. In this paper, in addition to electrochemical techniques (cyclic voltammetry and chronoamprometry), mathematical calculations and thermodynamic equations have been used to investigate the effect of ferric ion and pyrite on oxidation-reduction reactions of chalcopyrite. First, the oxidation-reduction reactions of chalcopyrite surface by cyclic voltammetry in acidic medium and then the effect of ferric ion addition on these reactions have been investigated. Then effect of pyrite presence along with the ferric ion (pyrite / ferric ion) is studied by the above method. The results of cyclic voltammetry method showed that ferric ion and pyrite increased the anodic and cathodic peak intensities and had a positive effect on chalcopyrite surface reactions. Also results of chronoamprometry and thermodynamic studies showed increase of free energy of chalcopyrite oxidation reaction in the presence of pyrite which was -22.45 kJ/mol.