Metodologia para simulação e escalonamento de prensas de rolos

Abstract

High pressure grinding rolls became suitable for hard rock grinding applications due to the development of roll liners capable of lasting through enough operating hours. Consequently HPGR technology has become part a number of feasibility studies in green field projects due to its greater energetic efficiency when compared to the use of standard crushers and even SAG milling. HPGR technology can be considered new and tentative from the point of view of mineral processing. Scale-up systems for capacity and power consumption have been developed but they can be considered as coarse approximations as shown in this work. A procedure for the prediction of the product size distribution has been developed here based on a population balance model that considers two phenomena: bed breakage under compression, which is the desired mechanism, and breakage by direct roll contact which is undesired andmust be avoided. Bench scale tests (LABWAL) were carried out under several operating conditions. The relationships that exist among the operating and system parameters as well as the ore characteristics have been established and a methodology for characterization of grinding inthe HPGR have been developed that allow for predicting the product size distribution at any specific grinding pressure and roll diameter. The scale-up system was verified and calibrated against two pilot plant campaigns, one with an iron ore and the other with a copper ore.The main conclusions that can be drawn from this work are the good quality and accuracy of the scale-up system for predicting the product size distribution and the poor quality of the existing scale-up systems for capacity and power that are currently used in the industry and are accepted in the international literature.