Hakan Benzer

Modelling cement grinding circuits

Modelling and simulation studies were carried out at 26 cement clinker grinding circuits including tube mills, air separators and high pressure grinding rolls in 8 plants. The results reported earlier have shown that tube mills can be modelled as several mills in series, and the internal partition in tube mills can be modelled as a screen which must retain coarse particles in the first compartment but not impede the flow of drying air. In this work the modelling has been extended to show that the Tromp curve which describes separator (classifier) performance can be modelled in terms of d(50)(corr), by-pass, the fish hook, and the sharpness of the curve. Also the high pressure grinding rolls model developed at the Julius Kruttschnitt Mineral Research Centre gives satisfactory predictions using a breakage function derived from impact and compressed bed tests. Simulation studies of a full plant incorporating a tube mill, HPGR and separators showed that the models could successfully predict the performance of the another mill working under different conditions. The simulation capability can therefore be used for process optimization and design

Simulation of open circuit clinker grinding

A mathematical model has been developed for an open circuit two-compartment tube mill grinding cement clinker. Samples were collected of the feed and product, and inside the mill. In the laboratory, sizings were done between the top size and 2 μm, and the breakage distribution function of the clinker was obtained by using a twin pendulum apparatus. Modelling and simulation studies were carried out using the JKSimmet computer programme developed by the Julius Kruttschnitt Mineral Research Center. In order to confirm the validity of the approach an extra sampling survey was performed while the circuit was operating at different conditions. The product size distribution of the mill was predicted for the new conditions using simulation based on the model which had been developed. The observed and calculated size distributions agreed closely for the new conditions.

HPGR simulation from piston-die tests with an itabirite ore

The Minas Rio project, owned by Anglo American, has HPGRs in open circuit operated as a tertiary/quaternary crushing stage. Currently this type of equipment is designed from HPGR tests on laboratory scale and pilot scale tests. This paper presents a methodology for simulating HPGR from piston-die tests on laboratory scale and a mathematical model developed in Hacettepe University in Turkey. The parameters determined from the results of the piston-die tests were used to validate the HPGR testing on pilot scale. Finally, the model was used to predict the particle size distribution in the HPGR product on industrial scale.