List of phosphate rock beneficiation methods

The main gangue minerals in phosphate rock are silicate minerals, carbonate minerals, and siliceous substances such as quartz. Phosphate minerals and siliceous minerals have a large difference in buoyancy and are easy to separate. Similar buoyancy, difficult to separate.

1 Magmatic rock-type apatite

The main components of igneous rock-type apatite are fluorapatite and a small amount of chloroacetate, accompanied by elements such as vanadium, titanium, iron, and cobalt, and often coexist with minerals such as magnetite, silicate, and metasilicate.

The beneficiation method of igneous rock type apatite is mainly the flotation method. Inhibitors such as sodium silicate are used to suppress gangue minerals, and anionic collectors such as fatty acids are used to enrich phosphorus minerals in flotation froth to directly float apatite.

The P2O5 grade of a certain iron-phosphate ore is 3.5%. By using the positive flotation method, only adding a water glass regulator and new high-efficiency AW collector, the concentrate P2O5 grade is greater than 37%, the MgO content is less than 1%, and the recovery rate of P2O5 is More than 95% of the beneficiation index. The combined process of magnetic levitation is also commonly used to process magmatic rock-type apatite, and the iron concentrate is magnetically separated while phosphorus concentrate is flotation.

2 Sedimentary metamorphic rock-type phosphorite

The main constituent minerals of sedimentary metamorphic rock-type apatite are the same as those of igneous rock-type apatite, and often coexist with carbonate minerals (mainly dolomite), silicate minerals, and siliceous substances. Minerals (dolomite) affect the quality of phosphorous concentrate.

Because the phosphorus minerals embedded in the phosphorite have a coarse particle size and good floatability, the positive flotation process is commonly used to float the phosphorite. Sodium carbonate and water glass are used as regulators to inhibit the flotation of apatite by anion collectors such as carbonate minerals, silicate minerals, siliceous substances, and fatty acids. Xu Changlun et al. used a positive flotation process to process phosphorite in Hubei Huangmailing Concentrator Plant. Under the condition of raw ore P205 grade of 9.32%, the P205 grade of phosphorous concentrate was 33.5% and the recovery rate was 85.43%.

Due to the weathering of some sedimentary metamorphic rock-type apatites, the ore is loose, the mud content is high, the carbonate minerals are lost in large quantities, and the phosphate and siliceous minerals are relatively enriched. The scrubbing and desliming process is often used to pre-enrich phosphorus. . The scrubbing and desliming process is simple. The weathered phosphate rock is scrubbed or peeled in water to remove the surface mud and enrich the phosphorus minerals. However, this trade will produce a large number of scrub tailings, so it is often combined with the flotation process.

3 Sedimentary rock-type phosphorite

The P2O5 grade of sedimentary phosphorite is between 12% and 35%, most of which are low-grade ores with fine crystals and aphanitic, and the selectivity is the worst among phosphorus-containing minerals. According to the mineral composition of the ore, phosphorite can be divided into siliceous phosphorite, calcareous phosphorite, and silico-calcareous phosphorite. The reserves of these three types of phosphorite account for 20% of the total reserves of sedimentary phosphorite. %, 8%, 70%. Among them, the phosphorus-containing minerals are mainly fluoroapatite (collophosphite), the gangue minerals mainly include carbonate minerals such as dolomite and calcite, silicate minerals such as mica and clay minerals, and siliceous materials such as quartz and chalcedony. and a small amount of iron-containing minerals and carbonaceous substances.

The siliceous phosphorite can use sodium carbonate as a regulator, water glass as a siliceous mineral inhibitor, and anion collectors such as fatty acids to float phosphate minerals in a positive flotation process.

Zhang Xu et al. adopted a positive flotation process of 1 roughing and 1 sweeping for a high siliceous colloidal phosphate rock with a P2O5 grade of 25.41% in Yunnan and obtained a phosphate concentrate with a P205 grade of 30.62% and a recovery rate of 83.87%. In addition, when the degree of weathering of siliceous phosphorite is relatively deep, desliming should be carried out first, and then positive flotation should be carried out. Gao Yang et al. first performed desliming treatment on a low-grade high-magnesium collophosite with a P2O5 grade of 21.15% and a MgO content of 6.36% in Yunnan. The minerals after desliming were recovered by positive flotation. The obtained phosphate concentrate had a P205 grade of 33.05%, MgO content is 0.69%.