Fluorite, also known as fluorspar, has its main chemical composition CaF2, a relative density of 3.0-3.2, a Mohs hardness of 4, brittleness, and a melting point of 1270-1350°C. Fluorite is a relatively common mineral with a wide distribution. According to statistics from the United States Geological Survey in 2015, the world's identified fluorite resources are about 500 million tons, and the identified reserves are about 250 million tons. China's fluorite reserves rank third in the world, second only to South Africa and Mexico.

my country's fluorite resources generally show a trend of more in the east and less in the west, more in the south and less in the north. They are distributed in 27 provinces (regions) across the country, but concentrated in Hunan, Zhejiang, Mongolia, Jiangxi, Fujian, Henan and other provinces. There are many single-type fluorite deposits in my country, but the reserves are small; the number of co-associated fluorite deposits is small but the reserves are large. In a single fluorite ore, the CaF2 grade is generally 35%-40%, and the reserves of fluorite ore with a grade greater than 65% can be directly used as metallurgical-grade rich ore, which only accounts for 20% of the total reserves of a single fluorite deposit. In the fluorite ore associated with metal deposits, the grade of CaF2 in the ore is generally only 7%-20%. Although the associated fluorite deposits have a large amount of resources, they are of low grade and are often comprehensively recycled when the main minerals are mined. my country's large and medium-sized fluorite mining areas include Zhejiang Wuyi, Hunan Shizhuyuan, Hebei Jiang'an, Jiangxi De'an, Inner Mongolia Sumochagan Obao, Guizhou Qinglong Dachang, etc.

Fluorite utilization status

Fluorite is widely used as a non-metallic raw material with strategic significance. Fluorite can be divided into three categories according to its grade and use: (1) Acid grade fluorite used in the chemical industry, with a mass fraction of fluorite greater than 97%; (2) Metallurgical grade fluorite used in steelmaking and electrolytic aluminum, The mass fraction of fluorite is 65%-85%; (3) the ceramic-grade fluorite used in the construction of glass and ceramics in the building materials industry, the mass fraction of fluorite is 85%-95%. At present, the main consumption structure of fluorite in China is 13% for steelmaking, 8% for aluminum smelting, 29% for fluorochemical industry, 40% for cement and glass industry, and 10% for others. Hydrofluoric acid is a key intermediate product for realizing deep chemical processing of fluorine-containing resources such as fluorite and the development of fluorine chemicals. With the rapid development of China's fluorine chemical industry, more and more acid-grade fluorite resources are needed.

Types of fluorite ore and its beneficiation method

According to the different gangue minerals, fluorite ore can be divided into four types, namely, quartz fluorite ore, carbonate fluorite ore, barite fluorite ore and sulfide fluorite ore.

(1) Quartz-type fluorite ore: The main minerals are fluorite and quartz, and the content of fluorite can reach 80% to 90%.

Contains a small amount of calcite, barite and sulfide.

(2) Carbonate type fluorite mine: The main minerals are fluorite and calcite. The calcite content can reach more than 30%,

There is a small amount of quartz, sometimes composed of quartz calcite-fluorite type ore.

(3) Barite-type fluorite ore: The main minerals are barite and fluorite, with a barite content of 10% to 40%.

This type of ore is often accompanied by sulfides such as pyrite, galena, sphalerite, and sometimes the content of quartz increases, forming a quartz-barite-fluorite type ore.

(4) Sulfide-type fluorite ore: its mineral composition is basically the same as that of quartz-fluorite, but contains more metallic sulfur

Sometimes the lead and zinc content can reach industrial grade.

For quartz-type fluorite mines, mainly concentrates to reduce silicon. For fine-grained quartz-type fluorite ore, oleic acid or oxidized paraffin soap is generally used as a collector, sodium carbonate is used as a slurry pH adjuster, and water glass is used as an inhibitor. The process flow of stage grinding stage separation is adopted. After many selections, high-quality fluorite concentrate can be obtained.

For carbonate-type fluorite minerals, since both fluorite and calcite minerals contain calcium ions and their solubility is similar, there is mutual transformation between minerals when they coexist in the solution, which makes it difficult to separate fluorite and calcite . Generally, water glass or salted water glass or acidified water glass is used to inhibit carbonate, oleic acid or other fatty acids as collectors of fluorite; in the range of pH 8 to 9.5, both calcite and fluorite can be oiled The acid is well collected, and inhibitors need to be used to adjust the difference in the floatability of the two minerals, so as to realize the separation of the two.

For barite-type fluorite mines, due to the similar floatability of barite and fluorite, the separation of fluorite and barite is also a difficulty in the process of fluorite flotation. Generally, sodium carbonate is used as a regulator, water glass is a gangue inhibitor, and oleic acid is used as a collector. Mixed flotation is used to obtain a mixed concentrate of fluorite and barite, and then the mixed concentrate is subjected to fluorite and barite flotation. Separate. There are two methods for separating fluorite and barite: one is to inhibit barite flotation of fluorite, and the other is to inhibit fluorite from flotation of barite. Studies have found that trivalent cations such as Al3+ and Fe3+ can inhibit barite and activate fluorite. On the contrary, divalent barium and lead salts can activate barite and inhibit fluorite.

For sulfide-type fluorite ore, use xanthate or black medicine to first float the sulfide, and then use fatty acid collectors to float the fluorite concentrate.

Conclusion

my country's fluorite ore resources are rich in reserves, but the average grade is low, making it difficult to sort. In terms of fluorite ore beneficiation, stage grinding, stage separation, and multiple selection are the main processes of fluorite flotation. However, this process has disadvantages such as complex structure, wide area and high energy consumption. Therefore, simplifying the structure of the beneficiation process and exploring new ball milling equipment and flotation equipment are important research directions for fluorite separation. As the latest generation of grinding equipment, the center drive ball mill is widely used in non-ferrous and fluorite mines. Judging from the use of the ball mill in fluorite mines such as Pengyuan, Hengdong and Fu'an, Hunan in the past ten years, the grinding efficiency has been significantly improved , Play a certain role in improving the efficiency of fluorite mines. The new flotation machine has the advantages of high beneficiation efficiency, large enrichment ratio, simple equipment structure, simplified process flow, small floor space, low equipment investment cost, high degree of automation, and simple operation and maintenance.