Iron ore reserves are limited, the taste is low. The content of fly ash in more than 5%, selected from fly ash rich iron beads, can also add some iron ore source, and after the election after the end of the gray iron, refractory quality of fly ash improved, can create conditions for other use way. It can be seen that the quality of fly ash, such as the quality has improved, to create conditions for other use. It can be seen from the fly ash in the separation of iron rich micro beads is one of the economic value of the use of ways. Fly ash in the iron rich vitreous body in addition to a small amount of soluble in dense glass beads (amount of iron content of iron rich glass beads with yellow, brown, red, black and other colors), the vast majority of magnetite and hematite were shaped to form a bead shaped particles. Rich iron bead size less than 45 microns, the relative density of about 4.2, is characteristic of low activity, and the magnetic conductor, high strength, good fluidity, ash can reach 15% of the total.
A magnetic separation process from fly ash separation of Fe rich microspheres, the main reference in the beneficiation technology, the method is simple, but because of the different ways of power plant ash, magnetic separation process can be divided into two kinds of dry and wet magnetic separation magnetic separation, the wet magnetic separation process is more mature.
1 dry magnetic separation
Dry magnetic separation is mainly used for dry fly ash, through the magnetic separation machine side of the iron concentrate, one side of the tailings. Dry magnetic separation as the material layer is too thick, often the upper ash difficult selection of magnet, low recovery rate, but also because of the dust stick wrapped, silicon and aluminum particles containing more concentrate, concentrate products that taste is not high, and the equipment is difficult to seal, dust pollution, these are dry method to iron improvements.
2 wet magnetic separation
Magnetic separator is installed under the wet dust collector, using natural separation into mortar drop separator, which is a magnetic separation, after the separation of Fe rich microspheres tend to grade up to 46%-50%, so the selection process should be added, namely the two grade separation, grade up to 56%, while the SiO2 content can be up to 16% of the following.
In the selection of roughing before, in order to avoid the powder produced with residual adhesion phenomena through demagnetization or flushing process, impurities washed and micro magnetic gangue net iron grain etc.. Only with the mud pump slurry will take off or after the flush into the magnetic selection process, to provide rich iron bead grade to select when.