اثر فعال سازي مكانيكي بر ليچينگ كنسانتره سولفيدي مس سرچشمه

چكيده انگليسي :

The effect of mechanical activation on the leaching of Sarcheshmeh copper sulfidic concentrate Saeid Vafaeian saeid v s@yahoo com Date of Submission 21 August 2010 Department of Materials Engineering Isfahan University of Technology Isfahan 84156 83111 IranDegree M Sc Language FarsiSupervisor Mehdi Ahmadian Assist Prof ahmadian@cc iut ac irAbstractPresently in industry the main amounts of copper are extracted by the pyrometallurgy methods particularlyfor the sulphide ore On the other hand the hydrometallurgical methods have been so far well benefited forthe oxide ores within the scale of industry too but because of some serious difficulties for the solubility ofsulphides the hydro processes for the sulphides have not yet found their applications in the industry scale Nevertheless many researchers have worked on this subject during the last decades mostly in the laboratoryscale This research work has been planned to evaluate principally the effect of mechanical activation as anaffecting agent in increasing the leaching efficiency and also some other parameters i e the time ofgrinding the time of leaching the temperature and the effect of oxygen purging affecting the efficiency ofcopper extraction from the concentrate The copper sulphidic concentrate was taken from the SarcheshmahMine and the leaching solution was 0 5 molar Sulfuric acid The main conclusions from the current research can be expressed as follows 1 The mechanical activation grinding before the leaching process could increase the leaching efficiencyquite obviously but this effect reaches a limiting optimum value of time after which the efficiency doesnot ascend any more and even descend to the lower values The XRD results for the concentrate sampleswhich were related to different time duration of grinding showed that the most structural variations happenedfor the samples which had been activated for 6 hours the time that we can accept as the optimum time 2 The SEM photographs also revealed this fact that during the mechanical activation grinding two types ofphenomenon can simultaneously occur first decreasing the particles size as the primary purpose of milling and second the agglomeration of particles As the main effect of agglomeration is the reduction in specificarea so this effect can obviously descend the chemical reactions between the leach liquid and the concentratematerial resulting less efficiency for the copper extraction However this phenomenon can be accepted asthe main reason for descending the leaching efficiency after the time duration of grinding reaches an amountwhich was about 6 hours in our experiments 3 The leaching temperature could affect the leaching efficiency by two opposite effects simultaneously ascending the leaching efficiency because of ascending the chemical reactions due to higher degree oftemperature and descending the reaction efficiency is attributed to the decreasing the amount of oxygen necessary for the chemical reactions within the liquid as the higher temperature causes less solubility ofoxygen This effect is more pronounced for the temperature degrees close to the boiling degree In order toprove this influential effect of oxygen some trial tests were performed in which the Argon gas was purgedinto the leach medium the results showed that nearly nothing was extracted On the other hand when in theother tests oxygen gas was purged into the leach the amount of copper extracted from the concentrate wasmuch high up to more than 95 and faster in comparison to the similar tests but without blowing oxygen 4 Investigating the leaching kinetics of the sulphide concentrate showed that based on the shrinking coremodel the rate controlling step in leaching of mechanically activated sample is attributed to the diffusionthrough the mass transfer boundary layer On the other hand for the leaching of the samples which have notbeen mechanically activated the rate controlling step can be related to the diffusion through the productlayer Keywor

وفائيان، سعيد

اثر فعال سازي مكانيكي بر ليچينگ كنسانتره سولفيدي مس سرچشمه