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In this study, the response surface method is used to develop a model for analyzing and optimizing zinc leaching experiments. An investigation into the leaching kinetics of smithsonite in ammonium citrate solution is also conducted. A model of kinetics is studied in order to represent these effects. The experimental data show that an increase in the solution temperature, concentration, and stirring speed has a positive impact on the leaching rate, while an increase in the particle size has a negative impact on it. The optimal experimental conditions consist of a leaching temperature of 70 °C, ammonium citrate concentration of 5 mol/L, particle size of 38 µm, and rotational speed of 1000 rpm. Under these optimal conditions, the leaching rate of zinc from smithsonite is 83.51%. It is speculated that the kinetic model will change when the temperature is higher than 60 °C. When the temperature is lower than 60 °C, the leaching process is under the control of the shrinking core model of the surface chemical reactions. The calculated activation energy of the leaching reaction is equal to 42 kJ/mol. The model of the leaching process can be described by the following equation: <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mn>1</mn><mo>−</mo><msup><mrow><mfenced close="" separators="|"><mrow><mn>1</mn><mo>−</mo><mfenced open="" separators="|"><mrow><mi>x</mi></mrow></mfenced></mrow></mfenced></mrow><mrow><mrow><mrow><mn>1</mn></mrow><mo>/</mo><mrow><mn>3</mn></mrow></mrow></mrow></msup><mo>=</mo><mfenced open="[" close="" separators="|"><mrow><msub><mrow><mi>k</mi></mrow><mrow><mn>0</mn></mrow></msub></mrow></mfenced><mo>⋅</mo><msup><mrow><mo>(</mo><mi>C</mi><mo>)</mo></mrow><mrow><mn>0.6181</mn></mrow></msup><mo>⋅</mo><msup><mrow><mfenced separators="|"><mrow><msub><mrow><mi>r</mi></mrow><mrow><mn>0</mn></mrow></msub></mrow></mfenced></mrow><mrow><mo>−</mo><mn>0.5868</mn></mrow></msup><mo>⋅</mo><msup><mrow><mfenced separators="|"><mrow><mi>S</mi><mi>S</mi></mrow></mfenced></mrow><mrow><mn>0.6901</mn></mrow></msup><mrow><mrow><mi mathvariant="italic">exp</mi></mrow><mo>⁡</mo><mrow><mfenced separators="|"><mrow><mo>−</mo><mrow><mrow><mn>42</mn></mrow><mo>/</mo><mrow><mi>R</mi><mi>T</mi></mrow></mrow></mrow></mfenced></mrow></mrow><mo>]</mo><mi>t</mi></mrow></semantics></math></inline-formula>. This demonstrates that an ammonium citrate solution can be used in the leaching process of zinc in smithsonite as an effective and clean leaching agent.