The influence of temperature and some other factors on the biological and nonbiological oxidation of chalcopyrite, pyrite and copper sulfide

• Main Author: Palmer, Ezra Revier
• Format: Others
• Published: BYU ScholarsArchive 1961
• Subjects: Oxidation; Thermistors; Metallic oxides; Chemistry
• Online Access: https://scholarsarchive.byu.edu/etd/8322; https://scholarsarchive.byu.edu/cgi/viewcontent.cgi?article=9322&context=etd

The purpose of this study was: (1) to find the effect of temperature on the wet oxidation of chalcopyrite, pyrite, and copper sulfide over the biological and nonbiological range; (2) to determine the influence of ferrous and ferric iron and free oxygen(air) on the oxidation. The sulfide minerals studied were oxidized over a range of temperatures between 25° to 75° C. The optimum biological oxidation occurred near 35° C. The nonbiological oxidation was very slow at low temperatures but increased with increasing temperature. The effect of solutions used in leaching the various sulfides over the temperature range differred. A synthetic nutrient solution, containing only a source of phosphate and nitrogen, was more effective on the biological oxidation of pyrite than on copper sulfide at the optimum temperature. Tailings water, obtained from Bingham Canyon, Utah, was more effective on chalcopyrite over a long period of time than the synthetic nutrient. Ten times more chalcopyrite was oxidized at 70° C. than at 55° C. in a dilute solution of sulfuric acid. A dilute solution of ferrous sulfate had very little effect on the oxidation of the sulfides. Oxygen and ferric iron in oxidized tailings water were shown to affect the oxidation of chalcopyrite at 65° C. The ferric iron was reduced. In an atmosphere of nitrogen, ferrous iron in fresh tailings water was inactive on the oxidation of chalcopyrite. Oxygen is the primary oxidizing agent in the biological and nonbiological oxidation of sulfide minerals in the leaching process.