Luossovaara-Kiirunavaara AB (LKAB) is an international mining group that mines and processes iron ore in the north of Sweden. LKAB's main product is iron ore pellets. The demand for product quality on the market is constantly increasing and in the same time, the industry strives to keep the production costs as low as possible. One way to keep the costs down is to minimize the number of costly experimental tests by using simulation tools such as computational fluid dynamics (CFD). An important part of the pelletizing process is the grate-kiln. The grate-kiln dries, pre-heats and sinters the pellets with help of a burner before they cool off and being stored away. To get further understanding of how to optimize this process, LKAB has a pilot-scale experimental combustion furnace (ECF). In this project, focus has been on modeling the ECF and perform CFD calculations to disclose the flow in the ECF. The used model was a full scale version of the ECF and with aid of the commercial code Ansys CFX 18.2 the flow field and temperature distribution in the kiln has been investigated. Three different cases were simulated where the first one was a cold flow simulation, the second one was a hot flow with no combustion and the third one was a hot flow with combustion involved. The biggest difference between the results was how the combustion affected the flow field and the temperature in the kiln. One conclusion is that a steady state simulation is enough for determining some of the flow characteristics in the problem even though phenomenon such as vortex shedding can not be observed with a steady state simulation. To study the flame behaviour more in depth, a transient simulation is needed for these observations. The results are similar with previous work where the temperatureis in the same range.