Beneficiation process of phosphate rock

- Apr 25, 2018-

Beneficiation process of phosphate rock

Phosphorus has different applications in different fields, such as food, military, plant and so on. It plays a vital role in our production and life. The flotation of phosphate rock is also very important. Today, we have to introduce the mineral processing technology for phosphate minerals, including 6 commonly used methods such as flotation and so on.

1. flotation method: the phosphorus minerals in China generally contain high MgO, and the phosphorus minerals and gangue minerals are symbiotic and fine. Only flotation can be used to obtain better separation effect. Therefore, flotation is the most used method for mineral processing in China. Flotation includes direct flotation, reverse flotation, reverse positive and negative flotation and double reverse flotation. Direct flotation process and reverse flotation process are used more frequently in production practice. Direct flotation process uses effective inhibitors to inhibit gangue minerals in phosphate rock, and uses flotation reagents to enrich phosphorus minerals in flotation froth.

The beneficiation process has been successfully applied to the industrial production of magmatic apatite and sedimentary metamorphic type phosphite ore. The sedimentary type calcium silicate (Gai Gui) mass phosphorite is a world recognized refractory phosphate rock. Since the development of direct flotation process of "S" series inhibitors, breakthrough has been made in the ore dressing technology of this type of phosphate rock ore. Reverse flotation process: the reverse flotation process is mainly used for the separation of phosphorus minerals and dolomites. The inorganic acid is used as the pH value regulator of the pulp. The dolomite is floatate by the fatty acid collector in the weak acid medium, and the phosphate minerals are enriched in the grooved product. Its biggest advantage is to achieve normal temperature flotation, and the coarse granularity of the product is conducive to the post-processing of products. The technology has been successfully applied to the industrial production of phosphate rock in Weng Fu phosphate deposit.

2. scrubbing desliming process: in the middle of 60s, China began to study the scouring and desliming of Liuyang Phosphate Mine in Hunan, and achieved certain results. In early 80s, the Haikou phosphate rock in Yunnan was studied, and then extended to the low magnesium weathering ore in Dianchi area. At present, the technology has been successfully developed and applied to the production of phosphate rock in Dianchi area. The process is simple in principle and is purely physical beneficiation. The weathered phosphate rock will be washed or stripped in water to remove the surface mud and enrich the phosphorus minerals. The enrichment of this process is not so large that it can only increase the P2O5 grade by 3~5 percentage points. The more typical and better effect is the weathered ore of Haikou phosphate mine.

3. medium separation technology: the specific gravity difference between minerals is the key to heavy medium separation. China began to study in the mid 80s and found that the key of its technology lies in the strict control of the separation proportion between 2.8 and 2.9. Dense medium separation technology has broad prospects for development because of its high separation efficiency and low environmental pollution. In the long run, this technique may be expected to be a preselected operation, which will preclude most of the gangue from low grade phosphate ore, thus improving the effect of subsequent sorting operation.

4. roasting digestion process: This is a chemical beneficiation method, which is mainly used for carbonate type phosphate ores with very few silicate minerals.  CO2 was released by thermal decomposition of carbonate minerals at high temperature, then hydrated CaO and MgO into fine grain Ca (OH) 2 and Mg (OH) 2, and the calcium and magnesium hydroxide was removed by classification technology to enrich the phosphorus minerals. The process has obtained good results in the selection of Shaanxi ho Jia Yan, Guizhou Weng Fu and Datang phosphate ores, and has completed the expansion test. However, due to the high energy consumption, difficult treatment of the removed lime milk, and the difficulty of production control, it has not been widely applied.

5. chemical beneficiation: this method is mainly used to exclude carbonate minerals, especially MgO, so that the MgO content in concentrate can be reduced to less than 0.5%. Because the processing cost is high, only when the concentrate quality of other beneficiation processes can not meet the requirements of subsequent processing can we consider using this technology to treat the concentrate. In phosphate ore chemical separation, ammonium carbonate, sulphuric acid and sulfur dioxide are used as extractant for carbonate minerals, and sulfuric acid is the most widely used.

6. photoelectric sorting technology: Optoelectronic beneficiation is based on chromatic aberration between ore and gangue to replace manual hand selection; it is seldom used in phosphate rock production. China has conducted optoelectronic sorting research on Kaiyang Phosphate Mine, which is mainly used for sorting out the roof dolomite mixed with mining and obtaining certain results.