Magnetic separator is a key equipment for quartz sand purification,
responsible for removing magnetic impurities such as Fe ₂ O Ⅲ from raw materials
(with a required iron content of ≤ 0.05% in the finished product). If the iron
removal effect is poor (iron content exceeds 0.1%) and the magnetic field
strength decays quickly (decays by more than 30% after six months of use), it
will lead to substandard product quality and limited downstream applications.
Based on practical experience, summarize the three-step troubleshooting method
to quickly restore the iron removal performance of the equipment.
Step 1: Check the magnetic system and drum - the core components determine
the iron removal effect
Improper magnetic configuration or drum wear are the main causes.
Poor magnetic material or incorrect arrangement: The magnetic field strength
of ordinary ferrite magnetic system is low (≤ 10000Gs), making it difficult to
remove weak magnetic impurities; The arrangement of magnetic blocks is chaotic
(not arranged in an "N-S alternating" manner), and the magnetic field gradient
is insufficient. It is recommended to use neodymium iron boron magnetic system
(magnetic field strength 12000-15000Gs) for deep iron removal of quartz sand,
fixed in a "spacing of 50mm, alternating arrangement" manner to ensure uniform
magnetic field coverage. If the magnetic system decays, use a Gaussian meter to
detect and replace the magnetic block when the surface magnetic field is below
8000Gs.
Wear or deviation of the drum shell: The wear of the drum shell (made of
stainless steel) exceeds 2mm, and the magnetic field penetration power
decreases; Deviation leads to insufficient contact between the material and the
magnetic field. Replace the 304 stainless steel shell (thickness ≥ 5mm) and
calibrate it with a level during installation to ensure that the drum is
parallel to the material trough with a deviation of ≤ 1mm. Install an anti
deviation device to avoid deviation during operation.
Step 2: Calibrate operating parameters - parameter deviation reduces iron
removal efficiency
Improper settings of drum speed, feed rate, and layer thickness directly
affect the iron removal effect.
Speed too fast or too slow: When the speed exceeds 30r/min, the material
stays on the surface of the drum for a short time (less than 3 seconds), and
magnetic impurities fall off before being adsorbed; Below 15r/min, material
accumulates and the magnetic field cannot penetrate the underlying material. Use
a tachometer to detect and adjust to 20-25r/min, ensuring that the material is
"thinly spread and slowly moved" and fully contacts the magnetic field.
Overloading or uneven feeding rate: exceeding the rated processing capacity
(such as 30t/h, actual 40t/h), material layer thickness exceeding 10mm, and
difficulty magnetizing the bottom layer material; The feeding fluctuates
greatly, and the iron removal effect fluctuates greatly. Use an electronic belt
scale to control the measurement and maintain it at 80% -90% of the rated value.
Install a fabric feeder to ensure even thickness of the material layer (5-8mm)
and avoid local accumulation.
Step 3: Adaptation of materials and daily maintenance - raw material
issues+maintenance deficiencies exacerbate malfunctions
Inadequate material characteristics and maintenance can affect the stability
of iron removal.
High moisture content or coarse particle size of materials: if the moisture
content exceeds 8%, the materials will agglomerate and magnetic impurities will
be wrapped; Particle size exceeding 5mm, insufficient magnetic field
penetration, and incomplete iron removal. Before magnetic separation, a drying
process (reducing moisture to below 5%) and a crushing and grading process
(particle size ≤ 3mm) need to be added to improve iron removal efficiency.
Maintenance deficiency: excessive dust accumulation or adsorption of iron
filings on the surface of the magnetic system, resulting in shielding of the
magnetic field; The lack of oil in the bearings leads to unstable drum speed.
Clean the surface iron filings and dust of the magnetic system with a brush
every day to avoid accumulation; Check the bearing temperature (≤ 65 ℃) weekly
and add lithium based grease; Tighten the fixing bolts of the magnetic block
every month, check the magnetic field strength every quarter, and promptly
supplement the decaying magnetic block.
By following the above three steps, the iron content in quartz sand can be
reduced to below 0.05%, and the stable attenuation rate of magnetic field
strength can be controlled at ≤ 2% per month. If there are still problems, it is
recommended to contact the manufacturer to test the compatibility of the
magnetic system to ensure precise matching with the iron removal requirements of
quartz sand.