The selective separation of chalcopyrite from pyritic ores represents a major industrial challenge due to inadvertent copper activation. This study systematically investigates the batch flotation kinetics of a complex sulfide ore (Draa Sfar North, Morocco) using a first-order kinetic model ($R^2>0.916$). The impacts of pulp pH, chemical depressants, and specialized collectors were evaluated to optimize the copper/iron selectivity index ($S{I}_{Cu/Fe}$). The results reveal a high-alkalinity paradox: At pH 11.0, chalcopyrite kinetics experience a severe passivation bottleneck ($K_{i,Cu}=0.1330 {\min }^{-1}$). At pH 11.5, selectivity collapses ($SI=2.64$) due to persistent iron sulfide floatability ($K_{i,Fe}=0.2066 {\min }^{-1}$). Conversely, natural pH ($\approx 6.0$) provides a superior baseline ($SI=3.32$), where 40 g/t sodium cyanide (NaCN) yielded a peak index of $S{I}_{Cu/Fe}=10.25$. As an eco-friendly substitute, sodium lignosulfonate (LSNa) achieved outstanding performance ($S{I}_{Cu/Fe}=5.30$), reducing iron kinetics to their lowest level ($K_{i,Fe}=0.0356 {\min }^{-1}$) via ferric–anionic complexation. Furthermore, Danafloat 271 secured the highest collector-driven selectivity ($S{I}_{Cu/Fe}=5.03$) by suppressing the iron matrix ($K_{i,Fe}=0.0306 {\min }^{-1}$) following Hard–Soft Acid–Base principles. This study clarifies specific aspects of selective copper–iron flotation, demonstrating that natural pH circuits with green depressants or selective collectors offer a sustainable alternative.