In Bayer process, low temperature treatment of bauxite generally applicable to gibbsite in the presence of a significant amount of boehmite (>3%), requires a temperature increase and the addition of an additive to improve the leaching conditions. This research is based on improvement of low temperature leaching conditions 108 °C and the addition of lime during the attack of some types of bauxite in Guinea. TRUhat is Low Mono Grade Bauxite (LMG), Standard Metal Grade (SMG) and Fria Bauxite (BF). The results of this study confirm an improvement in the extraction yields. Additionally, it shows an increase in yields of two points when the lime dosage is low, and between 0.5 and 3% of the bauxite weight. Based on the mineralogical and chemical composition findings, minerals contain of SMG bauxites are difficult to decompose while BF bauxites are easy to process. Sougueta limestone was used for testing. After calcination, we obtained CaO added at a rate of: 0.3; 0.5; 1; 3 and 6% of the bauxite weight to finally obtain the highest leaching efficiency compared to the leaching efficiency of bauxite without addition. The best leaching rate obtained for LMG, SMG and BF are respectively: 89.01, 87.15 and 89.74% for additions of 1, 0.5 and 3% CaO respectively.