The mineral flotation process enhances the hydrophobicity of valuable minerals and the hydrophilicity of gangue minerals through a specific reagent regime. Under mechanical agitation, valuable minerals float to become concentrate, while gangue minerals sink to become tailings, thus separating the concentrate and tailings. It's crucial for new flotation workers to understand that the flotation of concentrate relies on the hydrophobic properties of the mineral surface—hydrophobic minerals repel water—and not on mechanical entrainment. The process should minimize mineral flotation due to mechanical entrainment.

Reagents added during flotation include collectors, frothers, and modifiers. Collectors selectively enhance the hydrophobicity of the target minerals, increasing the difference in hydrophobicity between the target and gangue minerals, facilitating attachment to air bubbles. Frothers produce numerous small, stable bubbles to aid in the bubble-mineralization process. Modifiers alter the properties of the minerals and pulp, promoting or inhibiting mineral flotation and flocculation/dispersion, and can also adjust pulp pH.

Flotation has key performance indicators: 1. Maximize recovery of target minerals; 2. Minimize gangue minerals in the concentrate product. Therefore, collectors and modifiers with strong collecting ability and selectivity across different mineral intergrowths are needed. However, collector strength and selectivity are often contradictory: strong collectors often have poor selectivity, while highly selective collectors may lack sufficient collecting power (many reagents lack both collecting power and selectivity). Flotation operators must prioritize key issues and balance competing factors when establishing a reagent regime.

The primary influencing factor is the type and amount of collector used, which determines the dosage of frothers and modifiers.

Collectors generally lack frothing ability. Without a frother, even if a collector efficiently collects minerals, they will remain suspended in the pulp rather than attaching to bubbles and floating, preventing separation from gangue minerals. However, some collectors have inherent frothing properties, such as dodecylamine, eliminating the need for added frothers.

Xanthates are excellent collectors for sulfide ores, selectively enhancing the hydrophobicity of sulfide minerals without causing gangue minerals (e.g., quartz and calcite) to float. However, xanthates are less effective for oxide ores. To float oxide ores using xanthates, their surface properties must be altered to resemble sulfides. A common method is adding sodium sulfide as a modifier to the pulp. The sodium ions adsorb onto the mineral surface, creating a sulfide-like surface suitable for xanthate collection.

After determining the type and amount of collector, the next step is to select an appropriate reagent regime based on the specific situation.

Amine collectors have exceptionally strong collecting power, floating almost any mineral. Their lack of selectivity necessitates improving flotation selectivity by adding selective depressants to suppress gangue minerals. Common gangue depressants include water glass, sodium hexametaphosphate, and sodium silicate.

The process of establishing a flotation reagent regime starts with the core issue, addressing the primary contradiction (collector), then the secondary contradiction (frother and collector). While the establishment of the collector addresses a general issue—strong collecting power and good selectivity—it also has specific aspects, as different collectors behave differently with different minerals. A case-by-case analysis, focusing on the primary contradiction and understanding the relationships between different contradictions, is essential for flotation operators.