In the production of quartz sand, the wheel bucket sand washer undertakes the
key task of removing clay, mud powder and other impurities in the raw materials.
The cleaning effect directly determines the cleanliness of the finished sand -
if the ore washing is not thorough, the mud content of the finished sand exceeds
the standard (such as the required mud content of sand for construction ≤ 3%,
and the required sand for glass ≤ 0.5%), which will affect the subsequent
magnetic separation and screening accuracy, reduce the strength and quality of
the finished sand, and lead to the slow sale of the product. Many quartz sand
enterprises have encountered the problem of "unclean" and "low efficiency" of
the wheel bucket sand washer, but it is difficult to accurately locate the
cause. As a professional manufacturer specialized in research, development and
manufacturing of quartz sand ore washing equipment, we combined with a large
number of project practices to find out the core causes and systematic solutions
for poor ore washing effect and excessive silt content, helping enterprises
break through ore washing bottleneck.
Define "problem determination": scientifically define abnormal ore washing
effect
Before troubleshooting, check and observe whether the ore washing effect is
really unqualified to avoid misjudgment:
Silt content test: continuously sample 3 times (1kg each time) from the
discharge outlet of sand washing machine, and test the silt content according to
the standard method of Sand for Construction (GB/T 14684-2022). If the test
results exceed the production requirements (such as the requirements for
high-purity quartz sand ≤ 0.3%), it can be judged that the silt content exceeds
the standard;
Visual observation: Observe the appearance of finished sand. If the sand
surface is attached with obvious mud film and sticky by hand, or the turbidity
of wastewater discharged from the sedimentation tank is high (it cannot be
clarified for a long time), it indicates that the ore washing is not
thorough;
Efficiency determination: record the processing capacity of the sand washing
machine in unit time. If the actual processing capacity is 20% lower than the
rated value of the equipment (e.g., the rated capacity is 50t/h, but the actual
capacity is only 40t/h) and the ore washing time is extended, it can be
determined that the ore washing efficiency is low.
Step 1: Troubleshoot the core structure of equipment - "ore washing parts"
are the key
The core structures of the bucket wheel, water tank and drive system of the
bucket wheel sand washing machine directly affect the ore washing effect, and
the incomplete ore washing will be caused by the abrasion of parts and
unreasonable design.
Wear or improper angle of bucket wheel blade
Problem performance: the bucket wheel blade is seriously worn (the edge is
blunt and there is a gap), the material cannot be stirred effectively, and the
clay and mud powder are difficult to be stripped from the sand surface; Blade
angle deviation (such as too large or too small angle) leads to too short
retention time of materials in the wheel bucket, insufficient ore washing, or
too much material accumulation and failure of smooth unloading.
Cause analysis: high hardness of quartz sand, abrasion caused by long-term
friction of blade; The blade is not fixed according to the design angle during
installation (standard angle is generally 15 ° - 25 °), or the blade deforms and
the angle deviates after long-term use.
Solution: replace the blade with excessive wear and select high-chrome alloy
wear-resistant blade (the wear resistance is more than 40% higher than the
ordinary steel plate blade); Re-adjust the blade angle and fix it with gaskets
or bolts to ensure the angle of each blade is consistent (error ≤ 2 °); Install
the blade protection device (such as the blade edge welding wear-resistant
strip) to extend the service life of the blade. It is recommended to check the
blade wear quarterly.
Inappropriate water level and flow velocity of water tank
Problem performance: the water level of the water tank is too low (lower than
1/2 of the bucket radius), the materials cannot be fully immersed, and the clay
is difficult to be softened and stripped; If the water level is too high, the
water flow will slow down, and the washed mud powder cannot be discharged with
the waste water in time, and it will be re-adhered to the sand surface; Too fast
water flow will take away a large amount of fine quartz sand, resulting in waste
of raw materials; The velocity is too slow, mud powder deposits at the bottom of
the water tank and blocks the drainage outlet.
Troubleshooting method: Observe the water level in the water tank. If some
blades are not immersed in water when the bucket wheel rotates, it indicates
that the water level is too low; If the effluent from the outfall is clear but
the finished product has a high silt content, the water flow rate is too slow;
If the wastewater is turbid and carries a large amount of fine sand, it
indicates that the water flow is too fast.
Solution: adjust the inlet valve and control the water level of the water
tank at 2/3 of the bucket radius to ensure that the materials are fully
immersed; Control the water flow velocity by adjusting the drain valve or
installing a flow controller. When washing materials with high sludge content,
properly increase the water flow velocity (1.5-2m/s) to accelerate the discharge
of sludge powder; When washing materials with low mud content, reduce the water
flow velocity (1-1.5m/s) and reduce the loss of fine sand; Regularly clean the
sludge deposited at the bottom of the sink (weekly recommended) to avoid
blocking the drain.
Step 2: analyze operating parameters and material characteristics -
"adaptability" affects ore washing efficiency
If the operating parameters of sand washing machine, such as rotating speed
and feeding amount, as well as the mud content and particle size of quartz sand
raw materials are not matched, the ore washing effect will be poor directly.
The wheel bucket speed is too fast or too slow
Problem performance: when the rotating speed is too fast, the materials stay
in the wheel bucket for too short time (less than 10 seconds), the clay is
unloaded before it is fully stripped, and the silt content exceeds the standard;
When the rotating speed is too slow, the agitation frequency of the wheel bucket
is low, the ore washing efficiency is reduced, and the materials are easy to
accumulate in the wheel bucket, resulting in poor unloading and reduced
processing capacity.
Troubleshooting method: measure the actual rotating speed of the wheel bucket
with a tachometer and compare it with the applicable rotating speed recommended
in the equipment specification (e.g., the applicable rotating speed of the wheel
bucket sand washer with a diameter of 2.2m is 8-12r/min) to judge whether it
deviates from the reasonable range.
Solution: adjust the motor frequency converter parameters or replace the
drive pulley (change the transmission ratio), adjust the rotating speed to the
appropriate range - when processing the materials with high sludge content
(>10%), appropriately reduce the rotating speed (8-10r/min) and extend the
ore washing time; When processing materials with low sludge content (<5%),
increase the rotating speed (10-12r/min) and improve the efficiency; The mud
content of 3 batches of finished products shall be inspected continuously after
adjustment to ensure stable compliance.
Overload or uneven feed
Problem performance: the feeding capacity exceeds the rated capacity of the
equipment (such as rated capacity of 50t/h, actual feeding capacity of 60t/h),
the materials in the wheel bucket are piled too thick to be fully stirred during
ore washing, and there is a lot of clay left; The feeding is variable (such as
20t/h in a certain period and 60t/h in a certain period), which causes the
material volume in the water tank to fluctuate, the water level and water flow
speed are difficult to adapt, and the ore washing effect is unstable.
Troubleshooting method: use electronic belt weigher to continuously monitor
the feed volume for 1 hour, record the peak value and valley value, and
calculate the fluctuation amplitude (normally ≤ 10%); Observe the discharging
condition of the wheel bucket. If the material is caked and the surface has mud
during discharging, it indicates that the feed is overloaded.
Solution: Reduce the feeding speed of the feeder, control the feeding
quantity within 80% - 90% of the rated value of the equipment (e.g. rated 50t/h,
actually controlled within 40-45t/h), and avoid overloading; Install the
material level sensor and the feeder to form a closed loop control. When the
material amount in the wheel bucket is too high, the feeding will be
automatically reduced, and when the material amount is too low, the feeding will
be increased to maintain the uniform feeding; Larger grit washers or additional
grit lines (operating in parallel) may be used instead of forced overloading if
increased capacity is required.
The silt content of the material is too high or the clay has strong cohesive
property
Problem performance: the mud content of raw material exceeds 15%, or the clay
has strong cohesive property (such as kaolin clay). During ore washing, the clay
is easy to form "mud film" on the sand surface and difficult to be washed and
stripped by water flow; Clay will also block the wheel bucket screen, causing
the washed mud powder unable to be discharged and re-adhesive to the finished
sand.
Solution: add the pre-washing process before ore washing, use the spiral sand
washer for coarse washing, and remove most free clay first; If the clay has
strong viscosity, add appropriate amount of dispersant (such as sodium
hexametaphosphate, add 0.1% - 0.3%) in the water tank to reduce the clay
viscosity and promote the mud powder stripping; Replace the wheel bucket screen,
select the screen with smaller mesh (for example, replace it with 16 mesh for 10
meshes), and reduce the mesh diameter to ensure smooth discharge of mud powder
and avoid blocking.
Step 3: Inspect, maintain and assist the system - "Day after Day Guarantee"
is indispensable
Improper daily maintenance of sand washing machine and failure of auxiliary
system (such as water supply and drainage system) will indirectly reduce the ore
washing effect.
Insufficient pressure or poor water quality of water supply system
Problem performance: the water supply pressure is insufficient (lower than
0.3MPa), the water flow cannot effectively scour the clay on the sand surface,
and the ore washing is not thorough; Due to poor water quality (high mud content
and impurities), the external clay is brought into the water tank during water
supply, resulting in secondary pollution of finished sand and increased mud
content.
Troubleshooting method: measure the water supply pressure with a pressure
gauge. If the pressure is lower than 0.3MPa, it indicates that the pressure is
insufficient; Observe the water supply quality. If the water is turbid and has
obvious sludge, it indicates poor water quality.
Solution: check whether the water supply pump is faulty, and replace the
high-power water pump (ensure the water supply pressure ≥ 0.4MPa); Install a
filter on the water supply pipeline to filter sludge and impurities in the
water; If the mud content of water source is high, sedimentation tank can be
built to pre-treat the water supply to ensure clear water quality.
Equipment maintenance missing (aging and blocking of parts)
Problem performance: The wheel bucket screen is blocked (mud powder is
accumulated in the screen hole), and the washed mud powder cannot be discharged,
so it is re-adhered to the sand; The gear and bearing of the transmission system
are worn due to lack of oil, resulting in unstable wheel bucket speed and
reduced ore washing efficiency; A large amount of mud powder is deposited at the
bottom of the water tank, which affects the water flow circulation and leads to
poor ore washing effect.
Solution: establish the "weekly maintenance" system, clean the mud powder
blocked by the wheel bucket screen (wash with a high pressure water gun, with
water pressure of 0.5-0.8MPa); Fill the gear and bearing of the transmission
system with lubricating grease regularly (once every 3 months, select lithium
base lubricating grease); Clean the sludge deposited at the bottom of the water
tank every week, and install a blow-off valve at the bottom of the water tank
for quick blow-off; The equipment shall be overhauled every half a year and the
aged parts (such as worn gear and bearing) shall be replaced to ensure the
stability of equipment performance.
Preventive measures: 4. Ensure stable and efficient operation of the bucket
wheel sand washer
Solidification and dynamic adjustment of parameters: for specific quartz sand
materials, determine the optimal wheel bucket rotating speed, water level, feed
volume and other parameters through tests, and input them into the equipment
control system for solidification; Dynamic fine adjustment of parameters
according to the change of mud content of raw materials (such as increase of mud
content in rainy season) to ensure the stability of ore washing effect.
Material pretreatment: before ore washing, the raw materials shall be
screened and impurities removed to remove large impurities and part of free clay
and reduce the load of sand washing machine; For materials with high mud content
and strong viscosity, pre-washing or adding dispersing agent shall be carried
out in advance to improve ore washing efficiency.
Regular maintenance and parts replacement: maintain the equipment according
to the frequency of "weekly inspection - monthly maintenance - annual
inspection", clean the screen and water tank in time, replace the wearing parts
(such as blades and screens), and select wear-resistant parts to extend the
service life.
Intelligent monitoring and early warning: the sand washing machine is
equipped with an online silt content detector to monitor the silt content of the
finished sand in real time. When the silt content exceeds the standard, it will
automatically alarm and prompt the adjustment parameters; Install water level
and speed sensors to ensure that the operating parameters are always within a
reasonable range.
As a professional manufacturer of quartz sand washing equipment, we can
customize the bucket wheel sand washing machine and supporting systems (such as
pre-washing equipment and water supply system) according to the mud content of
raw materials, production capacity demand (10-200t/h) and finished product
standard of customers, and provide the full-cycle service from "process design -
equipment manufacturing - installation and commissioning - operation and
maintenance training". If your bucket wheel sand washer has problems such as
poor ore washing effect and excessive silt content, please contact our technical
team at any time, and we will quickly solve them through remote diagnosis or
on-site troubleshooting; At the same time, we can also provide equipment
upgrading services (such as installing intelligent monitoring system and
replacing wear-resistant parts) to help you improve ore washing efficiency and
finished product cleanliness and ensure the quality of quartz sand
production.