Influence of heating rate on the burning of cement clinker

The effects of heating rate on the burning of cement raw mix are analyzed in view experiments. Raw mix is produced from limestone, loam, and sand, then granulated and burnt in the gradient furnace to produce clinker. To investigate the dependence of burning of raw mix on heating rate, two different heating regimes were applied. The first heating regime was final temperature 1450 °C, burning duration 145 min, and rates of heating 29.5 and 3.85 K/min. The second heating regime was final temperature 1410 °C, duration 112 min, and rates of heating 36.4 and 5.3 K/min. As a result of microscopic investigations, it was noted that there were no significant differences between two clinker samples in terms of the sizes, forms, and distributions of free CaO, alite, and belite crystals. The amount of free CaO is the most important criterion for the burning of raw mix using a definite heating regime. Although there is a lower temperature and shorter burning duration, 2.09% free CaO is found in the clinker sample because of the high burning rate. It has been concluded that the clinker can be burnt at a lower temperature and for a shorter time with a high heating rate.