I. Core Application Scenarios

1. Metal Mineral Roasting (Mainstream Scenario)

• Oxidation Roasting: Mainly used for sulfide ores (chalcopyrite, sphalerite, galena, etc.). It removes impurities such as sulfur and arsenic from ores through high-temperature oxidation, converts sulfides into oxides, and facilitates subsequent leaching or flotation to recover metals;

• Magnetization Roasting: For weakly magnetic iron ores such as hematite and limonite, it converts them into strongly magnetic magnetite through roasting, improves magnetic separation efficiency, and is especially suitable for the resource utilization of low-grade iron ores;

• Volatilization Roasting: Used for processing ores containing volatile metals such as antimony and mercury. The metal compounds are volatilized at high temperatures and then recovered by condensation to achieve metal purification.

2. New Construction and Commissioning of Small and Medium-sized Metal Mines

3. Technical Renovation and Capacity Expansion of Old Mines

4. Low-grade Ore and Tailings Treatment

5. Temporary/Mobile Roasting Operations

II. Suitable Models and Core Advantages

1. Main Suitable Models

• Used Rotary Kiln (Φ2.2×45m-Φ3.2×50m): Suitable for small and medium-sized metal mines with a daily roasting capacity of 500-2000 tons, applicable to the roasting of conventional metal ores such as iron ore, copper ore and zinc ore;

• Used Vertical Rotary Kiln: Small in size and low in energy consumption, suitable for small-scale roasting in underground or small mining areas, especially for on-site processing of low-grade ores;

• Used Internal Heating Rotary Kiln: High thermal efficiency and uniform roasting, suitable for oxidation roasting of sulfide ores and pretreatment before heap leaching of gold ores, reducing energy consumption costs.

2. Core Advantages (From the Perspective of Metal Mines)

• Low Investment Cost: The price of used equipment is only 30%-60% of that of new equipment, which greatly reduces initial equipment investment, eases the capital pressure of mines, and shortens the payback period by more than 30%;

• Fast Commissioning: Spot supply, no need for customized production, short installation and commissioning cycle (15-30 days), and production can be achieved in as fast as one month, quickly realizing production capacity;

• Strong Adaptability: The rotation speed and temperature can be flexibly adjusted according to the type of metal ore (iron ore, copper ore, etc.), ore grade and roasting process to meet different production needs;

• Controllable Risk: Used rotary kilns have stable residual value, which can be leased or resold according to production needs in the later stage, reducing the risk of equipment idleness. Moreover, core components (kiln body, supporting roller, transmission device) are durable and can operate stably for a long time after maintenance;

• Low Maintenance Cost: Spare parts are highly versatile, the purchase cost of wearing parts such as kiln lining and supporting roller is 40% lower than that of new equipment, and the maintenance technology is mature, without the need for professional customized maintenance services.

III. Selection and Operation Points (Key to Avoid Pitfalls)

1. Core Selection Indicators

• Kiln Body Condition: Check the thickness of the kiln body (remaining thickness ≥70% of the original thickness), no cracks, deformation, severe corrosion, the integrity rate of the kiln lining ≥80%, to avoid frequent maintenance in the later stage;

• Core Components: Check the wear of supporting rollers, rolling rings, transmission devices (gears, motors), ensure good insulation performance of the motor, stable transmission without abnormal noise, and normal hydraulic deviation adjustment system;

• Process Adaptation: Select the kiln type according to the ore type and roasting process (oxidation, magnetization). For iron ore, prioritize the magnetization rotary kiln; for sulfide ore, prioritize the internal heating oxidation rotary kiln, matching the daily roasting capacity demand;

• Equipment Source: Prioritize formal used equipment dealers and equipment eliminated by mine technical renovation, and ask for equipment factory certificate, maintenance records and operation ledgers to avoid refurbished machines and major repaired machines.

2. Operation and Risk Control

• Preliminary Maintenance: After purchase, conduct a comprehensive inspection of the kiln body, transmission system and sealing device, replace aging kiln lining and seals, and ensure the tightness of the equipment (reduce heat loss and energy consumption);

• Environmental Adaptation: Roasting of metal ores will produce flue gas, which needs to be equipped with used dust removal and desulfurization equipment to ensure that flue gas emissions meet environmental protection standards and avoid environmental risks;

• Reserve Budget: Reserve budget for wearing parts (kiln lining, supporting roller) and daily maintenance. The annual maintenance cost of used equipment is about 15%-25% of the purchase price;

• Operation Specifications: Equip professional operators, strictly control roasting temperature and rotation speed, avoid overheating and ring formation of the kiln body, and extend the service life of the equipment.

IV. Application Cases (Reference)

• Small and Medium-sized Iron Mine: Purchased a used rotary kiln (Φ2.5×40m) equipped with a cooler and conveyor, with a total investment of about 1.2 million yuan, used for magnetization roasting of hematite, processing 800 tons of low-grade iron ore per day, increasing the magnetic separation recovery rate by 15% after roasting, and recovering the investment in 8 months;

• Copper Mine Technical Renovation: The old copper mine added a used rotary kiln (Φ3.0×45m) for oxidation roasting of chalcopyrite, completed installation and commissioning in 18 days, increased roasting capacity by 50%, and saved 60% of the technical renovation investment compared with new equipment;

• Remote Gold Mine: Used a used mobile rotary kiln for pretreatment before heap leaching of gold ore, flexibly transferred to 3 working faces, reduced ore haulage costs, and obtained an additional annual income of 200,000 yuan by leasing after the project was completed.

V. Summary