Flotation has been the focus of researchers as one of the most important processes of mineral processing. The importance of studying and optimizing ore circuits has led researchers to articulate processes toward mathematical methods until Mathematical methods along with laboratory methods lead to circuit design, cost savings and time savings. Kinetic models are fundamental models used to evaluate and analyze the flotation process and they are important for optimizing, simulating and controlling the flotation process. The parameters influencing the flotation kinetics include particle size, particle size distribution, particle shape, type of reagents and their amount, air flow rate, pulp density, amount of wash water, etc. The purpose of this study was to optimize the parameters affecting galena flotation by considering the interaction of collector, frother and pH parameters on metallurgical conditions, and then investigate the effect of primary feed particle size and liberation of galena mineralization on flotation kinetics. First, by studying the liberation of galena mineralization to achieve optimum crushing rate, the primary feed materials after crushing and grinding were divided into three dimensions of +106, -106 +75 and -75 micron and with the degree of freedom studies, it was found that the galena mineral reaches the appropriate degrees of freedom at -106 +75 micron. Then, experimental design software was used to optimize and model the amount of chemicals consumed, including collector, frother and pH. Lead recovery and grade were considered as the responses and the influence of parameters on responses was evaluated. Interaction of parameters on responses was investigated using two-dimensional, three-dimensional, and cantor plots and it turned out that the selected parameters are interactive. The optimum values of collector, frother and pH for maximum recovery were 350 g/t, 26 g/t and 8.5, respectively. In the study of six kinetic model classic model, Classical first-order model, Second-order kinetic model, First-order model with rectangular distribution of flotabilities, Second-order model with rectangular distribution of flotabilities, Fully mixed reactor model, Improved gas/solid adsorption model for galena flotation kinetics were used. After achieving optimum quantities of flotation chemicals according to the purpose of this study to investigate the effect of particle size and degree of freedom on flotation kinetics, the materials were first divided into three section (+106, -106 +75 and -75 micron) and flotation experiments were performed on each fraction separately and the kinetics of foaming were done and after drawing the cumulative recovery-time diagram, the models were fitted to the laboratory data and suitable models were obtained for each dimension fraction. The classical first-order model was more consistent with the large particle size flotation (+ 106 ?m) and for the other two dimensional fractions, all models were suitable. The buoyancy kinetics were small for coarse particle size (+106 micron) and the kinetics increased with decreasing particle size and finally, a decrease was observed for the fine particle size (-75 micron). Microscopic and degrees of freedom studies on floating materials at different flotation-time scavenging sites revealed that the degree of freedom release of particles that float early differs from those that float at end-points. We therefore considered floating materials at 0-30 seconds and 120-240 seconds as materials with high degrees of freedom and low degrees of freedom, and performed flotation kinetics experiments on them. For this reason, two experiments were performed for all the high-freedom and low-freedom materials by fixing all the factors that were effective on the flotation. Suitable for both degrees of freedom of classical and first order classical models with a rectangular distribution and was found to decrease with decreasing degree of constant kinetic freedom