Is the efficiency of the large quartz sand jaw crusher low and the wear fast?
Full analysis of reasons and solutions
Jaw crusher is the "first checkpoint" in the coarse crushing process of
large-scale quartz sand production lines (daily processing capacity ≥ 3000t),
responsible for crushing the quartzite waste (particle size ≤ 1500mm) mined in
the mine to a qualified particle size of ≤ 300mm, directly determining the
production capacity and subsequent process loads of the entire production line.
In actual operation, many enterprises may encounter problems such as crushing
efficiency lower than 60% of the rated value and jaw plate service life less
than 500 hours, which not only leads to capacity lag, but also significantly
increases operation and maintenance costs due to frequent replacement of parts.
This article combines the Mohs 7 high hardness characteristics of quartz sand,
accurately disassembles the root cause of the problem, and provides practical
optimization solutions.
1、 Core problem breakdown: 3 major root causes of low efficiency and fast
wear and tear
After extensive on-site research, it was found that the core problems of
large quartz sand jaw crushers mainly stem from three dimensions: firstly, the
insufficient adaptability of jaw plate material and structure, which cannot
resist the high-strength impact wear of quartz sand; The second issue is
improper control of crushing parameters, resulting in mismatched jaw speed,
discharge port clearance, and material characteristics; The third issue is the
lack of operation and maintenance of the feeding and lubrication system, which
leads to equipment overload and component jamming.
2、 Targeted optimization plan: Improve performance from the root
Option 1: Upgrade jaw plate configuration to solve the core pain points of
fast wear and tear
Traditional manganese steel jaw plates, due to insufficient hardness (HRC ≤
55), are prone to surface pitting and edge collapse when subjected to high-speed
impact from quartz sand, which is the main reason for rapid wear. It is
recommended to replace the high chromium alloy composite jaw plate with a base
material of 40Cr to ensure toughness. The working layer should be welded with
high chromium cast iron (thickness ≥ 15mm, hardness of HRC62 or above). The wear
resistance is 3-4 times that of ordinary manganese steel, and the service life
can be extended to over 1500h. Simultaneously optimizing the tooth profile
design of the jaw plate, adopting a "deep tooth+staggered arrangement" structure
(tooth height 25-30mm, tooth pitch 50-60mm), enhancing the grasping ability of
large quartzite blocks, reducing slipping and idling, and improving crushing
efficiency by more than 20%. During installation, it is necessary to ensure that
the jaw plate is tightly fitted with the moving and fixed jaws, and the pre
tightening torque of the bolts should be controlled at 450-500N · m to avoid
loosening and increasing wear during operation.
Plan 2: Accurately regulate crushing parameters to improve crushing
efficiency
Parameter imbalance is a key factor in low efficiency: too low a jaw rotation
speed (<200r/min) can lead to a long crushing cycle, while too high a speed
(>300r/min) can cause excessive material impact and exacerbate wear. It is
recommended to stabilize the jaw speed at 240-260r/min through a variable
frequency speed control system, taking into account both crushing efficiency and
equipment loss. The adjustment of the discharge gap should be combined with the
target particle size, and the coarse crushing stage should be controlled at
25-30mm. If the gap is too large, it can easily cause overload in subsequent
processes, and if it is too small, it will increase the crushing resistance. A
digital gap adjustment device can be installed for real-time monitoring and
precise calibration, with a deviation controlled within 1mm. In addition, the
eccentricity of the eccentric axis is adjusted according to the particle size of
quartzite waste, and for large blocks (>1000mm), the eccentricity is adjusted
to 18-20mm to enhance the impact force.
Plan 3: Optimize the feeding and lubrication system to ensure stable
operation
Uneven feeding and overload can cause frequent equipment shutdowns, and
lubrication failure can exacerbate component wear. The feeding end needs to be
equipped with a vibrating material feeder and a grid screen (aperture 1500mm) to
remove oversized impurities (>1500mm) to avoid material jamming, and to
evenly distribute the material along the width of the jaw plate. The thickness
of the material layer should be controlled at 1/3-1/2 of the length of the jaw
plate to avoid local overload. Equipped with an electronic belt scale and
overload protection device, it automatically alerts and slows down when the feed
rate exceeds 90% of the rated value, and emergency stops when the load exceeds
120%. The lubrication system requires the use of high-temperature anti-wear
grease, and a regular lubrication mechanism should be established for key
components such as eccentric shafts and bearings. Lubricating grease should be
replenished every 8 hours of operation and completely replaced every 500 hours.
At the same time, a dust-proof sealing device (with a protection level of IP65)
should be installed to prevent quartz sand dust from entering and causing
lubrication failure.
3、 Key points of daily operation and maintenance
Daily inspection of jaw plate wear, discharge particle size, and equipment
vibration status is required; Clean up residual materials inside the equipment
every week and tighten loose bolts; Monthly calibration of crushing parameters
and lubrication system; Perform non-destructive testing on eccentric shafts and
bearings every quarter. Through the above optimization and operation measures,
the crushing efficiency of the jaw crusher can be increased to over 95% of the
rated value, the service life of the jaw plate can be extended by three times,
and the equipment failure shutdown rate can be reduced by 70%, providing a
guarantee for the stable and efficient operation of the coarse crushing process
in large-scale quartz sand production lines.