Multifunctional mineral processing agent, five key functions of sodium hexametaphosphate

In the mining field, mineral processing agents are mainly used in the flotation, leaching, extraction and other processes of ores, so as to improve the recovery rate of valuable minerals in ores. Common types include collectors, adjusters, frothers, inhibitors, and dispersants. As a multifunctional mineral processing adjuster, sodium hexametaphosphate will analyze its five key functions today.

Complexation inhibition: In complex ores where calcium-magnesium gangue minerals (such as calcite and dolomite) coexist with target minerals, sodium hexametaphosphate reagents can form stable complexes with calcium, magnesium and other ions in the slurry.

For example, in zircon flotation, sodium hexametaphosphate reduces the interaction between gangue and collectors by complexing metal ions on the surface of gangue such as feldspar and nepheline, thereby improving the recovery rate of zircon. In addition, the protective film formed by its complexation product can effectively prevent the secondary activation of gangue minerals and ensure the stability of the sorting process.

Ion shielding effect: Free metal ions (such as Fe³⁺, Al³⁺) in the slurry often destroy the flotation system through electrostatic adsorption or chemical reaction. Sodium hexametaphosphate combines with these ions to form insoluble complex precipitation, blocking their reaction path with the collector or mineral surface, reducing the consumption of reagents and the amount of collector.

Dispersion and depolymerization effect: For ores that are prone to mudification (such as limonite and copper oxide), the sludge particles are small and the surface charge and surface energy are high, which is easy to agglomerate. Sodium hexametaphosphate, as a dispersant, can achieve efficient dispersion of sludge through double-layer compression and steric hindrance effect, improve the concentrate grade, and reduce the iron loss rate of tailings.

Surface modification effect: Sodium hexametaphosphate can directionally regulate the hydrophilicity of the mineral surface. In phosphate ore flotation, it changes the surface charge of the mineral through selective adsorption. It can complex with Ca²⁺ on the surface of apatite, reduce the surface potential, enhance the electrostatic repulsion with anionic collectors, and reduce floatability; it can also complex with Al³⁺ on the surface of siliceous gangue, expose the hydrophilic Si-OH group, and strengthen its hydrophilicity. This achieves efficient separation of phosphate concentrate and gangue, and improves the quality of phosphate concentrate.

pH buffering effect: Sodium hexametaphosphate is weakly acidic (pH 5.5-6.5), which can buffer the pH fluctuation of slurry. In the flotation of copper, lead and zinc polymetallic ores, it can indirectly adjust the acid-base balance of the solution by hydrolysis and complexation with metal ions, and prolong the stability time of the optimal activity range (pH 8-10) of xanthate collectors; on the other hand, its complexation product is adsorbed on the surface of the mineral to form a pH response film, which ensures the stability of flotation indicators.