The main purpose of pyrophyllite beneficiation is to remove waste rock and impurities, improve the purity of ore, separate pyrophyllite ore from other paragenetic minerals and gangue, and further improve the grade of its concentrate to meet the needs of various industrial sectors. At present, the beneficiation methods of pyrophyllite at home and abroad mainly include hand separation, grinding and classification, magnetic separation, bleaching, flotation and their combined processes.
Foreign beneficiation processing technology
The beneficiation process of foreign pyrophyllite ore is relatively simple, and it also adopts hand selection, crushing, grinding and grading. For pyrophyllite products with high requirements, in addition to the above-mentioned operations, magnetic separation, bleaching, flotation and other operations and their combined processes are often used to improve product quality.
My country's mineral processing technology
The beneficiation level of pyrophyllite ore in my country is close to that of foreign countries, and the methods used are mostly hand separation, crushing and grinding, classification, magnetic separation, flotation and combined processes.
1. Hand selected
Part of the pyrophyllite ore with less impurities and high quality is controlled by means of visual inspection of its color, surface physical properties, sampling point selection and testing. In the stope, some waste rocks or low-grade pyrophyllite with high impurities such as iron are selected by manual selection to improve the quality of other parts of the ore. Some high-quality materials suitable for carving and other arts and crafts are also manually selected by means of naked eye observation. pyrophyllite concentrate. For example, in recent years, in Fuzhou Shoushan, Emei and other mining areas, through visual observation, sampling control and other means, the concentrate pyrophyllite products obtained by manual selection are directly exported to Japan, and the price of concentrate per ton reaches 30 US dollars. Another example is in Fuzhou Shoushan and other mining areas, experienced workers or artists use methods such as naked eye observation to select some high-quality pyrophyllite with good shape and high quality as materials for engraving seals and arts and crafts. General pyrophyllite dozens of times, hundreds of times or even higher.
2. Crushing, milling and grading process
At present, most pyrophyllite mines in my country are used in the refractory and ceramic industries. After the pyrophyllite for carving and the waste rock are manually selected from the raw ore, the rest is used as raw pyrophyllite for industrial use, which is bagged and sold to users after crushing, grinding and dry classification.
3. Magnetic separation process
Pyrophyllite ore is often accompanied by magnetite, limonite, hematite, and ilmenite, anatase, rutile and other minerals. When the content of iron and titanium in the ore deposit exceeds the requirements of the industrial sector, they should be removed, usually by magnetic separation. With the different types and contents of minerals in magnetic separation, the magnetic field strength and process structure used are also different. When the magnetic separation of iron and titanium minerals is extremely weak or non-magnetic minerals, they should be removed by flotation or chemical methods.
4. Flotation process
In some mining areas, pyrophyllite has low aluminum content and high quartz content. In order to separate pyrophyllite and quartz, the method of flotation is often used. Usually, silicate or fluorosilicate is added to the alkaline pulp as inhibitor, carbonate is used as pulp pH regulator, and fatty acid is used as collector for sorting: in acidic pulp, hf is used as inhibitor, Use long-chain amines or quaternary ammonium salts as collectors for flotation. This method can make pyrophyllite concentrate containing SiO2 below 3%, and the recovery rate can reach more than 85%.