Best Practices for Feeding Mineral Sizers

Introduction

In modern mining production, as the application scope of mineral processing equipment continues to expand, the load and power requirements of mineral sizers are increasing.

Unlike the main frame of gyratory crushers, which uses cast components, the main frame of mineral sizers is meticulously manufactured from heavy-duty welded plates, endowing the equipment with robust structural strength and durability.

During operation, the teeth—the primary wear components of the mineral sizer—can be replaced either directly inside the machine or by removing the shaft and placing it on a maintenance stand.

Teeth play a critical role in the mineral sizer’s workflow, not only gripping rocks and applying crushing force but also screening the passing material.

Therefore, the design of the teeth must meet these complex functional requirements while ensuring effective control of the upper limit of product particle size during wear and achieving an acceptable wear life.

Typically, the teeth are arranged in a pick-shaped pattern, with sharp tips to grip the rock. The width and shape of the teeth determine the effective screening opening area, so these areas must be able to withstand flow wear and wear under high normal forces.

As such, in the feeding stage of the mineral sizer, special attention must be given to adopting the correct feeding method to ensure the equipment operates efficiently and stably.

Preparations Before Feeding the Mineral Sizer

Material Characteristics Analysis

Hardness

The hardness of the material is an important factor affecting the operation of the Mineral Sizer. Harder materials, such as granite or iron ore, may cause significant wear on the crushing teeth of the equipment.

Therefore, it is necessary to assess the Mohs hardness of the material before feeding. If the hardness exceeds the design range of the equipment, a primary crusher and a secondary crusher can be used to reduce the difficulty of subsequent processing.

Moisture Content

The moisture content of the material directly affects the smoothness of feeding. High-moisture materials (such as coal or clay with a moisture content exceeding 10%) are prone to adhering to the equipment surface during feeding, causing blockages.

To prevent this, the material can be dried before feeding, or a dehumidification device can be installed at the equipment inlet to ensure the material enters the crusher in optimal condition.

Particle size distribution

The particle size distribution of the material determines the uniformity of feeding and the processing capacity of the equipment. If the particle size of the material varies too greatly (e.g., a mixture of large chunks and small particles), it may cause uneven feeding and affect the crushing effect.

It is recommended to screen the material before feeding to separate particles that are too large in advance, or to optimize the particle size distribution by adjusting the screen mesh specifications.

Sticky, Clumping, or High-Abrasion Materials

For sticky or clumping materials, such as wet coal or clay, anti-adhesive agents can be added before feeding, or hot air drying technology can be used to reduce material stickiness.

For high-abrasion materials, such as silica-rich ores, it is recommended to select feeders with stronger wear resistance and regularly inspect wear-prone components to replace them promptly, thereby extending service life.

Feeding equipment selection and adjustment

Vibrating Feeder

Vibrating feeders are suitable for most Mineral Sizer feeding scenarios due to their simple structure and convenient maintenance. They uniformly convey materials to the crusher through vibration, particularly suitable for processing smaller-sized, highly flowable materials such as coal or limestone.

When selecting a vibrating feeder, the appropriate model should be matched based on material flow requirements and equipment processing capacity.

Apron Feeder

For large, heavy materials such as raw ore or large rocks, an apron feeder is a more suitable choice. Its chain plate structure can withstand high impact loads, ensuring stable material conveyance.

When using an apron feeder, it is important to adjust the chain plate’s operating speed to avoid overloading the equipment due to excessive speed or reducing production efficiency due to slow speed.

Feed Speed Adjustment

Feed speed directly affects the crushing efficiency and output of the Mineral Sizer. Excessively fast feed speeds may cause equipment blockages, while excessively slow speeds may reduce production efficiency.

It is recommended to adjust the operating frequency of the feed equipment via a variable frequency drive based on the equipment’s rated processing capacity and material characteristics, ensuring that materials enter the crusher at a constant speed. Additionally, regularly inspect the operating status of the feeder to prevent uneven feeding caused by mechanical failures.

Feed Uniformity

Uniform feeding is key to improving crushing efficiency. In actual operation, the following methods can be used to achieve this:

Install a material level sensor: Monitor the material height in the hopper in real time and automatically adjust the feed rate.

Optimize hopper design: Ensure that the size and angle of the hopper outlet are suitable for material flow to prevent material buildup or flow deviation.

Regular cleaning: Avoid material clumping in the feeder or hopper, which affects uniformity.

Mineral Sizer Best Feeding Method

The way material enters the mineral sizer has a critical impact on equipment operation. Improper feeding methods not only accelerate wear on equipment components but also hinder normal operation, potentially leading to frequent unnecessary shutdowns.

To achieve optimal mineral sizer performance and reduce maintenance costs, it is essential to strictly adhere to the following best feeding practices.

Uniform Feeding

Distributing material uniformly across the entire length of the rollers is a critical step in ensuring stable equipment operation.

This feeding method helps maintain uniform wear rates on equipment components and wear-resistant plates, effectively preventing premature tooth replacement in high-wear areas, thereby achieving optimal material processing capacity.

For example, in actual production at a large mine, adopting uniform feeding extended the tooth replacement cycle by 30% and significantly improved production efficiency.

Central Feeding

In addition to uniformly feeding material across the entire length of the rollers, concentrating material feeding at the central position between the rollers is equally important.

Central feeding further reduces the risk of uneven wear on equipment components, optimizes material handling processes, and enhances overall production efficiency.

By precisely controlling the material feeding position, material is subjected to more uniform force within the screen, reducing equipment vibration and abnormal wear caused by uneven force distribution.

Avoiding Blocked Feeding

Mineral sizers are not suitable for blocked feeding, as this feeding method can cause a series of issues.

Blocked feeding can lead to accelerated tooth wear, increasing equipment maintenance costs;

simultaneously, a large influx of material into the equipment may cause material to surge within the machine, overflowing onto the conveyor belt below, resulting in material spillage—not only wasting resources but also increasing cleanup efforts;

Furthermore, excessive material in the hopper may cause unnecessary equipment downtime, severely impacting production progress.

To avoid blockage feeding, mechanical feeders can be incorporated into the design of the crushing plant.

Mechanical feeders can stabilize material flow control, ensuring that material enters downstream production processes uniformly and orderly.

Vertical feeding

When using a feeder to convey material to a screening machine, it is essential to ensure that the feeder’s width matches the length of the screening machine’s rollers, and that the material exiting the feeder is perpendicular to the screening machine’s rollers.

This ensures that the material is evenly distributed along the length of the rollers, maximizing the equipment’s processing capacity.

Pre-screening

Conducting screening operations before material enters the crusher offers numerous significant advantages.

First, by removing undersized material, the wear rate inside the screening machine is significantly reduced, extending the equipment’s service life.

Second, pre-screening reduces the overall production of fine particles, improving product quality and reducing the burden on subsequent processing stages.

Performance and Features of Mineral Sizer

Performance Advantages

First, the equipment has a compact design, allowing flexible layout in limited production spaces;

Second, it has a high crushing ratio, typically reaching 5–8, and operates with low noise levels, meeting modern environmental protection requirements;

Third, its simple structural design makes maintenance and servicing more convenient and efficient;

Fourth, it has extremely high production efficiency, with production rates 1–2 times higher than traditional tooth roller crushers;

Fifth, the crushed material has uniform particle size and low over-crushing rates, meeting strict particle size requirements across various production scenarios; Finally, the equipment is equipped with sensitive overload protection devices, ensuring safe and reliable operation and effectively reducing production risks.

Unique Features

Compared to other types of crushers, the mineral sizer has significant competitive advantages.

It not only has a high crushing ratio but also has no special requirements for the moisture content of the crushed material, preventing material adhesion and blockages.

Additionally, it has minimal over-crushing, effectively conserving resources. During operation, the equipment produces low noise, minimal vibration, and low dust emissions, significantly improving the working environment.

Furthermore, the equipment has low energy consumption and a small footprint, further reducing production costs and space requirements.

The equipment is also equipped with a hydraulic automatic retreat mechanism, which automatically avoids hard foreign objects such as iron blocks, effectively preventing damage to the tooth rollers, while also resisting interference from wooden blocks and flexible objects to the normal operation of the equipment.

The application of an intelligent cleaning device allows the equipment to automatically remove materials adhering to the walls of the crusher chamber during operational intervals, maintaining internal cleanliness and ensuring production efficiency.

Multiple protective devices and interlocking mechanisms provide comprehensive protection for the motor, crusher, and entire production system from mechanical, electrical, and hydraulic perspectives.

With its outstanding advantages of high efficiency, energy saving, and environmental protection, the mineral sizer has become the ideal choice for thermal power plants to replace imported crushers.

It is suitable for crushing brittle materials of medium to low hardness, such as bituminous coal, anthracite, lignite, coal gangue, sintered ore, coke, furnace slag, shale, and limestone.

Mineral Sizer Maintenance Plans

Lubrication Maintenance

Lubrication is a critical factor in ensuring the continuous and trouble-free operation of the mineral sizer.

Many equipment component failures are closely related to improper lubrication, such as contaminated lubricating oil, incorrect lubricant selection, insufficient lubricant quantity, or unreasonable lubrication frequency.

Through proper maintenance management and correct lubrication procedures, most of these failures can be prevented.

Specifically, we need to seal all lubricant storage containers to prevent dust, sand, and moisture from entering;

thoroughly clean all grease and oil lines before installation; wipe all lubrication points with a clean cloth before lubrication to prevent contaminants from entering equipment components;

establish and strictly enforce a regular lubrication schedule; take adequate precautions to prevent oil leaks and conduct regular visual inspections of equipment.

Additionally, note that motor bearings should not be over-lubricated and should be independent of the lubrication system;

Under extreme environmental temperatures or other special conditions, consult local lubricant suppliers for professional advice;

Understand the oil output per stroke of the grease gun to ensure accurate lubrication of components; Identify which components require manual lubrication.

Daily Maintenance

During daily operations, conduct a comprehensive inspection of the equipment every 12-hour shift.

Test all emergency stop switches to ensure rapid shutdown in emergencies; Inspect the equipment for loose or missing covers and protective devices;

Check if all bearing temperatures are too high; inspect the reducer for oil leaks, overheating, or excessive noise;

check the hydraulic coupling for oil leaks, overheating, abnormal noise, or loose components; inspect the motor temperature and operational noise;

verify that all lubrication and hydraulic hoses and fittings are free from leaks or damage;

inspect all instruments, cables, and electrical connections for damage; check the speed monitoring sensor for damage and confirm its operational status is normal.

Weekly Maintenance

Weekly inspections and maintenance should be conducted on the equipment. Check the tightness of all bearing housing fasteners;

inspect the reducer, motor housing, and motor fasteners for loosening; clean the motor’s heat sinks and fan to ensure proper cooling;

clear the ventilation openings on the motor housing; Clean the gear reducer housing; inspect the desiccant breather and replace as needed;

carefully listen for abnormal noises from the crusher shaft drive unit, automatic lubrication system, and hydraulic power unit;

if the screen is equipped with an oil purification system, wipe the surface of the oil purifier;

inspect all components of the hydraulic power unit, including the oil tank, hoses, and hydraulic cylinders, for leaks or damage.

Monthly Maintenance

A detailed inspection of the equipment’s critical components should be conducted monthly.

Inspect the wear, damage, and loosening, damage, or missing teeth of the crusher shaft and crusher bars;

check for material buildup on the crusher shaft, crusher bars, and liner scrapers; inspect the wear of the liners and check for missing liners;

inspect the fasteners of the crushing section and ensure proper bolt tension; inspect the fasteners of the crusher bars and ensure their bolt tension meets requirements;

Wipe down the hydraulic power unit and clean any oil residue and dust from the interior;

if the screen is equipped with an automatic lubrication system, inspect the cabinet components and interior for leaks, and wipe away any excess lubricant and dust from the interior.

Quarterly maintenance

A comprehensive fastener inspection of the equipment should be conducted quarterly, including wear-resistant plates and covers;

sample the gear oil in the reducer to test for contaminants and oil degradation; Check the backlash and axial alignment of the flexible elements of the hydraulic coupling; inspect the lifting ears for damage or corrosion.

Semi-annual maintenance

Every six months, inspect the gears of the gear coupling for damage or corrosion; if the equipment is equipped with an oil purification system, wipe the surface of the oil purifier again;

if the equipment has an automatic lubrication system, clean or replace the pump outlet filter.

Annual maintenance

Conduct a comprehensive structural inspection of the machine frame annually; inspect all hydraulic cylinder piston rods for corrosion; check the machine frame for corrosion and damage to the protective coating;

inspect exposed metal surfaces of shafts or drive components for corrosion; replace the hydraulic oil in the hydraulic power unit; if the equipment is equipped with an automatic lubrication system, clean or replace the lubricant injection filter.

Conclusion

Reasonable feeding methods and a scientific equipment maintenance plan are the core elements ensuring the efficient and stable operation of the mineral sizer. By following the above best feeding practices, we can effectively reduce equipment wear, improve production efficiency, and reduce maintenance costs.

Additionally, strictly adhering to the regular maintenance plan enables timely identification and resolution of potential equipment issues, extends equipment lifespan, and ensures the continuity and reliability of the entire production process.