Study On The Energesis Of Mechanically Activated Sulphide Ores

Mechanical activation is one of the most important methods to enhance the hydrometallurgical processes. The way and magnitude of mechanical activation of ores affect greatly the leaching process. The study on the energe changes of mechanically activated sulphide ores is made by calorimetry in order to investigate the relation between mechanically activated storage energy and structural change of ores, and to provide a fundamental basis for the mechanical activation to be further applied in the metallurgical field and for the improvement of enhancement method of hydrometallurgical processes. The main conclusions made are as follows:(1) Improvement of Calvet HT-1000 microcalorimeterThe Calvet HT-1000 microcalorimeter was manufactured by France SETARAM Corporation in 1989. In order to acquire the exact heat flow data online, improvement of interface between the main body of the calorimeter and computer was made by redesigning and setting-up a multi-function data acquisition card for the PC computer. A new calorimetric and data processing software with the functions such as integration, differential calculus and model building was developed in Windows 98 OS. The reliability of the calorimeter after improvement and the convenience of analysis of the heat flow data with the new software were proved by the experiments .(2) Three types of solid-liquid reactors of ampoul sampling reactor, pneumatic sampling reactor and pneumatic agitating reactor were designed and built in this paper so as to determine the reaction enthalpy of indissoluble solid during the leaching process. The paremeters of the calorimeter improved were calibrated systematically with a new electric caliboration device redesigned.(3) The prior energy releasing behavior of mechanochemically activated sphalerite and pyrite during heating was investigated by calorimetry for the first time. And the structural changes of mechanicallyactivated sphalerite and pyrite before and after the energy releasing were investigated using X-ray diffraction analysis, X-ray laser particle size analysis, etc. The results indicate that mechanically activated sphalerite and pyrite release part of the stored energy while being heated in the calorimeter. The particle size of the mechanically activated sphalerite and pyrite increases but the structure of cyrystal remains the same when they are heated in the calorimeter for the measurement of the prior energy releasing. Therefore, it can be concluded that the prior energy releasing is probably caused by the decrease of the specific surface area. As the prior energy releasing is related to the changes of the specific surface energy and the number of surface chemical active sites of the mechanically activated sulphide ores during aggregation, the order of the amount of energy releasing of ulphide ores is EsrFeS2 > EsrPbS > EsrZnS.The amount of the prior energy releasing of sulphide ores is related to the mill-ball meterials and independent on the mill-vessel meterials. It shows that the storage procedure of mechanical energy is very fast.The amount of prior energy releasing of mechanically activated sphalerite increases with the grinding time but remains almost constant after grinding for one hour. That of mechanically activated pyrite increases with the grinding time but decreases after grinding in N2 for 40 min and then maintains almost constant slowly . It is possibly related to the element S produced during the mechianical activation.(4) A new method to measure the mechanically activated stored energy of minerals was built by designing a thermochemistry cycle that made the mechanically activated and non-activated minerals reach the same final state while dissoluting in the some solution. The thermal behaviors of the dissolution of mechanically activated sphalerite and pyrite were investigated for the first time by calorimetry.The mechanically activated stored energy of sphalerite and pyrite increases with the increased grinding time.The increase of the specific surface energy of...