Manganese Ore Processing Technology: An Efficient Path to Unlocking Medium and Low-Grade Resources

Manganese, a key strategic resource for national economic development, plays an irreplaceable role in iron and steel smelting, electronic technology, aerospace industry, and other fields. As high-grade manganese ore resources are increasingly depleted, the efficient development of medium and low-grade manganese ores has become a core issue in ensuring resource supply. Advanced manganese ore processing technologies are becoming the key support to solve the problem of lean ore utilization and maximize resource value.

1. Magnetic Separation Technology: Precise Separation Based on Magnetic Differences

For weakly magnetic rhodochrosite, magnetic separation technology is an important means to achieve initial enrichment. Taking the medium and low-grade rhodochrosite in Tongren, Guizhou as an example, the raw ore has a manganese grade of only 10.70%, accompanied by gangue minerals such as quartz and chlorite, with severe argillation. Through the wet high-intensity magnetic separation process, under the optimized parameters of grinding fineness (-0.075mm accounting for 67.44%), slurry concentration (10%), and magnetic field intensity (640kA/m), a magnetic concentrate with a manganese grade of 16.73% and a recovery rate of 64.17% can be obtained at one time, meeting the standard of grade III rhodochrosite.

If the magnetic concentrate is further processed by the "magnetic separation-roasting" process, roasting at 900°C for 20 minutes can increase the manganese grade to 18.72%, but the recovery rate will drop to 49.84%. The core of this technology lies in utilizing the magnetic difference between rhodochrosite and gangue minerals, and achieving the initial separation of useful minerals and impurities by precisely regulating the magnetic field intensity and grinding fineness, laying a foundation for subsequent deep processing.

2. Flotation Technology: Micro-Separation Aided by Reagents

For manganese ores with fine dissemination and insignificant magnetic differences, flotation technology achieves efficient separation by regulating the surface properties of minerals, mainly including direct flotation and reverse flotation.

Direct flotation uses fatty acid-based reagent GJBW as the collector, sodium carbonate to adjust the slurry pH, and sodium hexametaphosphate to inhibit gangue. Under the conditions of grinding fineness (-0.075mm accounting for 88.58%), sodium carbonate (3000g/t), and GJBW (1500g/t), a concentrate with a manganese grade of 12.61% and a recovery rate of 65.78% can be obtained.

Reverse flotation uses dodecylamine as the collector and dextrin as the depressant to specifically remove gangue. When the grinding fineness is -0.075mm accounting for 88.58%, sodium carbonate is 1000g/t, and dodecylamine is 600g/t, the manganese grade of the concentrate reaches 12.84% with the recovery rate increased to 76.31%. The mechanism lies in the electrostatic adsorption between cationic components such as \(RNH_3^+\) dissociated from dodecylamine and the negative charges on the surface of rhodochrosite, realizing the selective collection of target minerals.

3. Magnetic-Flotation Combined Process: An Efficient Scheme with Complementary Advantages

A single process is difficult to balance grade and recovery, so the magnetic-flotation combined process has become the key to breaking the bottleneck. Using magnetic concentrate as raw material, after regrinding to -0.075mm accounting for 87.25%, adjusting the slurry pH to 7.9, and adding 800g/t dodecylamine, 1000g/t dextrin, and 200g/t HEDP depressant for reverse flotation, the final concentrate with a manganese grade of 18.44% and a recovery rate of 59.06% can be obtained, meeting the standard of grade II manganese ore (grade ≥18%).

This process gives full play to the initial enrichment advantage of magnetic separation and the fine particle separation capacity of flotation. Through the precise interaction between reagents and mineral surfaces (e.g., the interaction between HEDP and rhodochrosite is stronger than that of water molecules), it effectively overcomes the interference of argillation and realizes the efficient utilization of medium and low-grade manganese ores.

From the physical separation of magnetic separation to the chemical regulation of flotation, and then to the synergistic efficiency of the combined process, manganese ore processing technologies are constantly breaking through the boundaries of lean ore utilization. These technologies not only improve resource recovery but also promote the manganese industry towards green, efficient, and sustainable development, providing solid technical support for ensuring national strategic resource security.