The spiral sand washing machine is a key sand washing equipment for
large-scale quartz sand production lines (daily processing capacity ≥ 3000t),
responsible for removing mud powder and impurities on the surface of quartz sand
(required cleanliness ≥ 98%, finished sand moisture content ≤ 8%), directly
determining the grading and sales quality of finished sand. If the cleanliness
is insufficient (residual mud powder rate exceeds 5%) and the sand water
separation effect is poor (finished sand moisture content exceeds 12%), it will
cause the finished sand to clump, the grading to be disordered, and even fail to
meet the standards for construction sand. Based on the high hardness of quartz
sand and the large processing capacity of large-scale equipment, a three-step
troubleshooting method is summarized to quickly restore sand washing
performance.
Step 1: Optimize the spiral structure and speed configuration - the core
components determine the cleaning effect
The main reasons for poor cleaning are the wear of spiral blades,
inappropriate speed, or unreasonable spacing.
Poor adaptability or wear of spiral blades: ordinary steel plate blades are
used, which have insufficient wear resistance. After more than 5000 hours of
use, the blade thickness is reduced by more than 3mm, and the mixing force is
weakened; The blade pitch deviation exceeds 10mm, the sand water mixture is
uneven, and local mud powder cannot be peeled off; The deviation of the blade
installation angle exceeds 2 °, and the quartz sand has insufficient residence
time in the groove (<30s). Replace the high chromium alloy wear-resistant
blade (with a surface welding wear-resistant layer with a thickness of ≥ 5mm),
and accurately match the pitch (250-300mm) according to the sand washing
requirements; Calibrate the blade installation angle to 12-15 °, ensuring that
the quartz sand residence time is controlled within 40-60s, and thoroughly rub
and clean.
Unbalanced spindle speed: When the speed is below 18r/min, the spiral
stirring intensity is insufficient, and the mud powder is difficult to detach
from the surface of the sand particles; Above 28r/min, equipment vibration
intensifies (amplitude exceeding 2mm), sand and water splash severely, and it is
easy to cause fine sand loss (loss rate exceeding 3%). Calibrate the spindle
speed with a tachometer and stabilize it at 22-25r/min using a frequency
converter; According to the dynamic adjustment of the feed mud content, when the
mud content exceeds 8%, it should be appropriately increased to 25-28r/min, and
when the mud content is ≤ 5%, it should be reduced to 22-24r/min.
Step 2: Calibrate water flow parameters and feed control - precise control of
separation efficiency
Insufficient water flow intensity, overloaded feed, or imbalanced sand water
ratio can exacerbate the problem of sand water separation.
Inappropriate water flow parameters: The inlet flow rate is less than 80m
³/h, which cannot effectively remove the stripped mud powder; Above 120m ³/h,
the water flow impact force is too strong, and fine sand is lost with the
wastewater; The height deviation of the overflow outlet exceeds 50mm, the water
level in the tank is unstable, and the sand water mixing ratio is unbalanced.
Control the inlet flow rate through an electromagnetic flowmeter to stabilize at
90-110m ³/h, matching the rated processing capacity of the equipment; Adjust the
height of the overflow outlet to ensure that the normal water level in the tank
is 30-50mm away from the top of the tank. Install an automatic water level
monitoring device and make timely adjustments when the deviation exceeds
20mm.
Overloading of feed rate or uneven distribution of fabric: The feed rate
exceeds the rated value (such as 250t/h, actual 300t/h), the thickness of quartz
sand accumulation in the tank exceeds 500mm, and the sand and water cannot fully
contact each other; The feeding port is not equipped with a diversion device,
and the material is concentrated and impacted by the spiral, resulting in
insufficient local mixing. Strictly control the amount with an electronic belt
scale to maintain the feed rate at 85% -95% of the rated value; Install a
conical splitter to evenly distribute the material along the width of the
groove, avoiding dead corners caused by local overload during cleaning.
Step 3: Optimize wear-resistant protection and sand water separation - avoid
separation defects at the source
Insufficient wear resistance of the equipment, clogged screens, or abnormal
drainage systems can affect the separation efficiency.
Wear resistant parts wear or screen blockage: The lining plate of the tank is
worn out by more than 10mm, and quartz sand directly rubs against the tank,
producing secondary impurities; The pore size blockage rate of the dewatering
screen at the discharge end exceeds 30%, making it difficult to quickly separate
sand and water; The screen material is made of ordinary stainless steel, which
is easily worn by quartz sand and has a pore size deformation of over 2mm. The
polyurethane wear-resistant lining plate (with a service life three times that
of steel plate) is replaced, and a high wear-resistant stainless steel
dewatering screen (with a pore size set at 0.8-1.2mm according to the finished
sand grading) is selected; Install ultrasonic cleaning device to clean the
clogged aperture of the screen in real time, and manually check the integrity of
the screen every week.
Poor drainage system or backflow of tailwater: Insufficient diameter of
drainage pipeline (<300mm), obstruction of tailwater discharge, abnormal
water level in the tank; The unfiltered tail water flows back directly, and the
mud powder is mixed in again, which exacerbates the difficulty of cleaning.
Replace the large-diameter drainage pipeline (≥ 350mm) and install a pipeline
dredging device to avoid blockage caused by sedimentation of mud and powder;
Install a sedimentation tank and filter screen in front of the reflux pipeline,
and purify the tail water (with a mud powder content of ≤ 0.5%) before reflux to
improve sand washing efficiency.
Daily maintenance should pay attention to: checking the wear of spiral
blades, inlet flow rate, and screen blockage every day; Calibrate the spindle
speed and water level height every week, and clean the sediment powder in the
tank; Replace aging lining plates and check bearing lubrication every month;
Perform non-destructive testing on the spiral shaft every quarter and reinforce
weak areas. By implementing the above measures, the cleanliness of quartz sand
can be increased to over 99%, and the moisture content of finished sand can be
reduced to below 6%, ensuring stable quality of finished products on large-scale
production lines. If there are still problems, it is recommended to contact the
manufacturer to optimize the spiral structure and water flow design to match the
demand for large processing capacity sand washing.