Phosphate rock processing process

As an important strategic resource, phosphate ore is widely used in agriculture, chemical industry and national defence. With the increasing depletion of high-grade phosphorus ore, the efficient use of low-grade and complex and difficult to select phosphorus ore has become the focus of the industry. Phosphate ore beneficiation technology through physical, chemical and biological means to achieve ore enrichment and separation of impurities, of which the flotation process occupies a dominant position, and constantly combined with innovative technology to improve the efficiency of sorting.

In the traditional beneficiation process, scrubbing desliming is suitable for high degree of weathering ore, through mechanical scrubbing to strip the surface mud, but tailings treatment needs to be combined with flotation for further recovery. Re-election method makes use of the difference in mineral density, such as the application of heavy media cyclone in Yichang phosphate mine, can increase the grade of raw ore to 31.88%, but the recovery of fine-grained grade still need to be assisted by flotation. Flotation technology is the most flexible, for siliceous, calcareous or mixed silica-calcium phosphorite, derived from positive flotation, reverse flotation and combined processes. For example, Yunnan Haikou high silicon and high magnesium phosphorite lump rock using positive - reverse flotation process, concentrate recovery rate of 80%; Florida phosphate mine in the United States follows the ‘two-stage flotation method’, through the pharmaceutical control to achieve high efficiency sorting. Heavy magnetic flotation process is used for the comprehensive recovery of associated minerals, such as alum mountain phosphate mine first flotation apatite after magnetic separation of iron ore, to achieve simultaneous enrichment of phosphorus and iron. Roasting method decomposes carbonate impurities through high temperature, which is suitable for high carbonate phosphate ores such as Saudi Arabia, but energy consumption and equipment cost limit its wide application.

Emerging technologies have injected new vigour into phosphate ore dressing. Microbial treatment uses Bacillus subtilis, Aspergillus and other bacteria to decompose low-grade ore, and the phosphorus dissolution rate can reach 9.5%, which is both environmentally friendly and has economic potential. The dry electrowinning method breaks through the limitations of the traditional wet method and separates low-grade ores by friction charging, and the concentrate grade of the phosphorus ore in Qingshui Gou was increased to 30.23% after electrowinning. Magnetic cover cover method shows the selective separation advantage in the laboratory stage, while the selective flocculation process can deal with micro-fine grained ore, but the industrial application is still waiting for a breakthrough. The R&D of pharmaceuticals, such as low-temperature collector OT-8, amphoteric collector α-amino arylphosphonic acid and high-efficiency inhibitor W-98, has been promoted simultaneously, which significantly improves the selectivity and adaptability of flotation and reduces energy consumption and environmental pollution.