During the operation of the permanent magnet drum magnetic separator, there
is always a layer of iron powder on the surface of the drum that cannot be
completely unloaded. As the drum rotates back to the selected area, this iron
powder is carried into the concentrate, greatly reducing the iron removal
effect. Many customers think it's due to insufficient magnetic force, but in
fact, the problem lies more in the iron unloading process.
The most common reason is the wear or excessive clearance of the iron
unloading scraper. The gap between the scraper and the surface of the drum
should generally be controlled at 0.5-1mm. When the gap is too large, the iron
powder cannot be scraped clean and remains on the drum; If the gap is too small,
the scraper and drum will rub hard, accelerating their wear. It is recommended
to check the wear of the scraper every two weeks and replace it when the wear
exceeds one-third of the original thickness. When installing a new scraper,
calibrate the gap with a feeler gauge and maintain uniformity along the entire
length of the drum.
The adhesion of material on the surface of the drum will exacerbate the
difficulty of unloading iron. When the moisture content of the material is too
high or there is too much fine powder, the fine powder adheres to the surface of
the drum to form a thin shell, and the iron powder is stuck to the shell and
cannot be scraped off. The moisture content of the feed should be controlled
below 1%, and a hot air drying device should be installed before dry magnetic
separation. Clean the surface of the drum with a brush after each shift shutdown
to maintain a smooth finish.
The design of the magnetic enclosure angle is unreasonable, and the magnetic
field in the unloading area is not completely demagnetized. The magnetic
envelope angle determines the distribution of the sorting zone and the unloading
zone. If there is still a certain magnetic field strength in the iron unloading
area, the iron powder will be magnetically attracted and the scraper will not be
able to scrape it clean. The Gaussian meter can be used to measure the magnetic
field strength on the surface of the iron unloading drum, which should normally
be close to zero. If it is significantly higher, it is necessary to contact the
manufacturer to adjust the magnetic system angle or replace the magnetic
system.
During daily inspections, pay attention to observing whether the iron powder
discharge from the iron unloading port is continuous and clean. When residual
iron powder is found on the surface of the drum, adjust the gap between the
scraper first, then check the adhesive material on the drum, and finally check
the magnetic system. For equipment operation related issues, please call Manager
Zhang at 13583776655 (same as WeChat) at Shandong Heavy Industry.