This study aims at the recovery of energy by using the tertiary air and the secondary air emerging from the cooler at the cement plant Djawad Taher of Algeria, in order to increase the production of clinker and to minimize the amount of hot air pumping out of the firing line to recover energy. There are several cements plants in the world that uses technology of tertiary air, however, in the cement plant Djawed Taher it is not used. In this context we conducted a study on the recovery of the tertiary air based on mass and heat balances in the firing line. We have developed a program in MATLAB that does all the calculations. The overall results led us to important suggestions by proposing two solutions: The first solution is the increased production of the clinker in the presence of the tertiary air by keeping constant the flow rate of natural gas. The second solution is to increase the production of the clinker in the presence of the tertiary air with changing the debit of natural gas. The results show a very significant reduction in the air pumping in the second solution, with an increase in production but with some more consumption of natural gas.