Phosphate rock flotation process

1. Positive flotation process

The positive flotation process grinds the phosphate ore until the monomers are dissociated, adds water to the slurry to adjust it to a certain concentration, and uses a specific collector to enrich the useful phosphorus minerals. It is concentrated in foam products and uses specific agents to inhibit gangue minerals such as silicate and carbonate in phosphate rock.

2. Reverse flotation process

The reverse flotation process is mainly used for the separation of phosphorus minerals and dolomite gangue minerals. Inorganic acid is generally used to adjust the pH of the slurry to a certain range. , using a specific collector in a weakly acidic medium to enrich the dolomite into the foam product, leaving the phosphorus minerals in the tank. The elimination rate of dolomite gangue minerals can reach 70-80%. The ratio of dolomite elimination rate and P2O5 (phosphorus pentoxide) loss rate is generally (6-10):1.

3. The forward and then reverse flotation process

The forward and then reverse flotation process mainly processes silicocalcium phosphate rock. It first uses inorganic alkali to adjust the slurry to weak alkalinity. Use a specific collector to enrich useful phosphorus minerals in the foam product, and leave the silicate gangue minerals in the tank for elimination. The foam is the positive flotation concentrate, and then add inorganic acid to adjust the slurry to weak acidity. After the flotation concentrate (reground or not) is slurried, a collector is used to enrich carbonate impurities, leaving useful phosphorus minerals in the tank to obtain reverse flotation concentrate. The reverse flotation operation is mainly to remove MgO (magnesium oxide) impurities in phosphate concentrate.

4. Reverse first and then forward flotation process

The first reverse and then forward flotation process is in the opposite order to the first forward and then reverse flotation process. The first stage can grind the ore to -200 The mesh mass fraction accounts for 70 to 80%, and most of the carbonate has been dissociated from the monomer. First, use a collector to float out the carbonate gangue under acidic medium conditions to obtain the anti-floating concentrate, and then carry out the second stage of regrinding. When the siliceous gangue dissociates, the phosphorus mineral floats out under alkaline medium conditions, and the positive floating concentrate is obtained. The second stage grinding produces a fresh surface, which is more conducive to the separation of phosphorus and silicon. This process is similar to the forward and then reverse flotation process. It has strong adaptability to the raw ore, ideal final concentrate index, relatively low acid consumption, but increased alkali consumption. It is beneficial to reduce the cost of chemicals when using phosphoric acid as an inhibitor, but the selection It is difficult to recycle the factory's return water.

5. Double reverse flotation process

Double reverse flotation process is mainly used to separate phosphorus minerals from dolomite and quartz gangue minerals. Generally, inorganic acid is used to adjust the slurry to Weakly acidic, use fatty acid collectors to enrich dolomite gangue minerals in the foam, then use fatty amine collectors to enrich quartz gangue minerals, and finally leave useful phosphorus minerals in the coarse and fine mixed concentrates .