The flat magnetic separator relies on magnetic plates to adsorb iron
impurities in wet iron removal from quartz sand. After running for two to three
years, many customers have found that the iron removal effect is not as good as
before, and the iron content in the concentrate gradually exceeds the standard.
Using a Gaussian meter, the magnetic field strength on the surface of the
magnetic plate has decreased significantly compared to the new machine. Magnetic
demagnetization is a problem that permanent magnet equipment cannot be wound
around, but the demagnetization speed varies, depending on how many pitfalls
have been encountered during daily use.
The demagnetization rate of the magnetic plate will significantly increase if
it is exposed to high temperatures for a long time. Although neodymium iron
boron magnetic materials have strong magnetic force, their temperature
resistance is limited. After the working temperature exceeds 80 ℃, the magnetic
domain structure gradually becomes unstable and the magnetic force permanently
decays. If a flat magnetic separator is installed near a dryer or hot air duct,
the demagnetization speed of the magnetic plate will be several times faster
than normal operating conditions due to long-term heat radiation. Suggest
installing insulation boards between the magnetic separator and the heat source,
or adjusting the equipment layout to widen the distance. The cooling water
temperature should not be too high, and it is best to control the inlet water
temperature below 25 ℃ in summer.
The long-term adsorption of iron mud on the surface of the magnetic plate
without cleaning, while the magnetic field is shielded, is also accelerating
demagnetization. Some customers think that filling the magnetic board with iron
powder does not affect its use, as it will drop when the power is cut off. In
fact, the adsorbed ferromagnetic material will form a magnetic short circuit,
and the magnetic field lines will close inside the iron mud layer. The magnetic
plate itself is in an "overload" state, and over time, the direction of the
magnetic domains gradually deviates, and the magnetic field strength naturally
decreases. Rinsing the magnetic board once per shift to keep the surface clean
is more effective than any maintenance.
Mixing strong magnetic large iron pieces into the feed may also cause local
demagnetization when hitting the magnetic plate. Large iron pieces such as
broken steel bars and bolts are attracted by the magnetic plate and repeatedly
hit the surface of the magnetic plate under the impact of the slurry. The
magnetic domain structure at the impact point is destroyed, forming a local weak
magnetic zone. Install a grille or permanent magnet iron remover in front of the
flat magnetic separator to intercept large iron pieces in advance, which can
effectively protect the magnetic plate.
During daily maintenance, a Gaussian meter is used to detect the magnetic
field distribution on the surface of the magnetic plate once every quarter. If
it is found that a certain area is significantly low, and it is confirmed that
it is demagnetization rather than iron mud coverage, the magnetic plate can only
be replaced. Shanlu Heavy Industry has been serving in the field of quartz sand
magnetic separation equipment for many years and can recommend magnetic
materials with higher temperature resistance levels based on on-site conditions.
Encountering problems during equipment operation, welcome to contact the
technical team of Shandong Heavy Industry for communication: Manager Zhang
13583776655 (same as WeChat).