## 1 Introduction  
Fluorite (CaF\({}_{2}\)) has been classified as a critical non-metal mineral by the European Union for its economic importance and high supply risk [1]. Fluorite rarely occurs without gangue mineral in deposits. Minerals that usually occur with fluorite are barite (BaSO\({}_{4}\)), calcite (CaCO\({}_{3}\)), and quartz (SiO\({}_{2}\)) [2, 3]. CaF\({}_{2}\) presents a wide range of applications in chemical manufacturing, metallurgy, and the glass and ceramic industries. Nevertheless, high degrees of fluorite purity are required for different mineral applications. Thus, these less appealing fluorite resources require advanced beneficiation methods. Froth flotation is a selective process that is used to carry out specific separations of complex minerals, based on the different surface properties of each of them. It stands out in fluorite flotation as one of the physicochemical techniques with the highest performance [3]. To carry out the froth flotation process, it requires the addition of chemical reagents to the system. These flotation reagents are the collectors, depressants, activators, and modifiers, whose main actions are to induce and inhibit hydrophobicity of the particles and to give stability to the foam formed. Separation of fluorite from calcium minerals by flotation is difficult because they exhibit the similar surface properties [4, 5]. This is due to the presence of Ca\({}^{2+}\) cations on both surfaces [5, 6]. Fatty acids are known to adsorb onto the surface Ca\({}^{2+}\) ions [7, 8]. Thus, they display a lack of selectivity, inducing global flotation of the CaCO\({}_{3}\). However, the efficient flotation of fluorite from other calcium-bearing minerals has been reached using specific depressants [9; 10; 11; 12]. Depressants are vital to achieve desirable separation results in fluorite ore beneficiation. Depressants can be divided into three categories, namely, metal ions (Al\({}^{3+}\), Fe\({}^{3+}\), Mg\({}^{2+}\), Ca\({}^{2+}\), Fe\({}^{2+}\)), inorganic inhibitors (sodium silicate, sodium sulfide, and sodium hexametaphosphate), and macromolecular inhibitors (starch, tannin extract, and polyacrylamide) [13]. The main depressants used in the selective separation of fluorite from gangue minerals are tannin extracts [14]. Quebracho extract contains tannins that have good depressant ability of certain minerals as carbonates. Some authors have used mixtures of depressants to increase the efficiency of the fluorite flotation process [15; 16; 17]. QT is one of the most recommended depressants for this separation. [PERSON] and [PERSON] [17] conducted a review of different published works on the action of QT in the separation of fluorite and calcite. QT is widely recommended as a depressant in fluorite flotation because it depresses both carbonates and silicates [18]. When the QT is adsorbed on the mineral surface, it becomes hydrophilic. In addition, this work indicates that tannins have a negative surface charge due to the presence of phenolic groups and these react with the surface of the minerals by chemisorption, interacting with the collector that is being used, as is the case of oleic acid [19]. The electrokinetic potential of the mineral is slightly negative with the addition of small amounts of tannin. This negative surface charge repels anionic collectors causing depression, but attracts cationic collectors. Dextrin is also used as a depressant in the mineral processing industry for some calcite minerals. Dextrins are derivative of starch produced by partial thermal degradation under acidic conditions [20]. [PERSON] et al. [21] studied a fluorite flotation system and found that combination of tannin and dextrin improved the recovery of fluorite by 19.23%, the removal rate of CaCO\({}_{3}\) by 13.43%, and SiO\({}_{2}\) by 8.93%. This combination of dextrin and tannin appeared to exhibit considerable promise for depressing the impurities during fluorite flotation. On the other hand, QT can react with dextrins in the presence of surfactants.