The electromagnetic dry powder magnetic separator is used for micro powder
iron removal in quartz sand dry purification, but many customers overlook the
indicator of feed moisture content. When the moisture content of the material
exceeds the standard, the magnetic separator appears to be operating normally,
but the iron removal effect is quietly decreasing, and the iron content of the
finished product occasionally exceeds the standard.
When the moisture content exceeds 1%, the fine powder begins to agglomerate
and adhere. The prerequisite for the magnetic field effect of dry magnetic
separation is that the material particles are dispersed and can freely pass
through the magnetic field zone. After the moisture exceeds the standard, the
fine powder forms small clusters, and the magnetic impurities wrapped inside the
clusters are shielded outside the range of the magnetic field and enter the
concentrate together with the clusters. More troublesome is that damp materials
are prone to adhere to the magnetic medium and the surface of the magnetic
roller, forming a layer of material shell, which hinders the penetration of
magnetic lines and further reduces the adsorption capacity. It is recommended to
install an online moisture detector in front of the magnetic separator or take
samples for drying and testing every shift to ensure that the moisture content
of the feed is controlled below 1%.
When the moisture exceeds the standard, the cleaning cycle of the magnetic
medium will be significantly shortened. Under normal working conditions, the
magnetic medium can be cleaned once a week. When the moisture content exceeds
the standard, the adhesion speed of fine powder is fast, and the gaps in the
magnetic medium will be filled in two or three days, requiring frequent shutdown
for cleaning. The cleaning cycle can be appropriately shortened as a temporary
solution, but the fundamental solution is to control the moisture content of the
material from the source by adding a hot air drying device in front of the
magnetic separator or extending the drying time at the front end.
The high temperature and excessive moisture of the material lead to more
severe agglomeration. When the discharge temperature of the dryer is too high,
it directly enters the magnetic separator, and the hot material condenses inside
the equipment when it encounters cold air, causing the fine powder to stick and
become sticky. It is recommended to leave a natural cooling conveying section
between the dryer and the magnetic separator, and wait for the material
temperature to drop below 40 ℃ before entering the magnetic separator.
During daily inspections, pay attention to observing whether there are lumps
or adhesion on the surface of the magnetic medium. If the cleaning cycle is
significantly shortened, check the moisture content of the feed first.
Encountering problems during equipment operation, welcome to contact the
technical team of Shandong Heavy Industry for communication: Manager Zhang
13583776655 (same as WeChat).