Mining And Metallurgy Rotary Drum Dryer 25TPH Rotary Dryer Machine

Rotary Drum Dryer

1.Product Introduction

Rotary Dryer core structure is a cylindrical steel shell, usually installed at a slight inclination to the horizontal line. The shell is driven to rotate by gears, and its weight is supported by rollers and bearings. The inner wall of the shell is equipped with lifting flights, which continuously tumble and shower the material during rotation to significantly increase the contact area between the material and the heating medium, thereby accelerating the drying speed. During the drying process, wet material is fed from the inlet at the higher end and gradually moves toward the discharge outlet at the lower end under the combined effect of the lifting flights and the inclination of the shell. The heating medium (such as hot air or flue gas) contacts the material in either a co-current (same direction) or counter-current (opposite direction) manner to achieve dehydration through heat and mass transfer.

2.Application

Its applications are extensive, primarily covering the following fields:

• Mining and Metallurgy:Used for drying concentrates of metallic and non-metallic ores (such as magnetic, gravity, and flotation concentrates), coal slime, slag, and aggregates. Its high-temperature resistance and high-throughput capabilities make it the critical equipment for dehydration stages in mineral processing.

• Building Materials Industry:Widely applied in cement production for drying raw materials like clay and limestone, as well as auxiliary materials such as gypsum and fly ash.
• Chemical and Environmental Protection:Utilized for treating chemical sludge, industrial waste residues, and chemical raw materials (such as salts and catalysts). It facilitates waste-to-resource conversion and ensures compliant emissions.
• Energy Industry:Used for the pre-drying of low-grade fuels like coal slime and lignite to enhance combustion efficiency; it is also employed for the dehydration of biomass fuels such as wood chips and straw.

3.Working Principle

The Rotary Dryer (also known as a drum dryer or rotary kiln dryer) is a continuous drying apparatus widely utilized in industries such as mining, construction materials, and chemical processing. Its core operating principle relies on direct contact between hot airflow and wet materials within a rotating cylinder. By utilizing counter-current or co-current heat transfer methods, the equipment achieves highly efficient material dehydration.

Core Operational Workflow

1. Introduction of Materials and Heat Source Wet materials are transported via belt conveyors or bucket elevators into a hopper, then fed through a charging pipe into the elevated end of the dryer drum. Simultaneously, the drying medium—hot air or flue gas—enters from the lower end (counter-current) or the upper end (co-current) of the cylinder.

2. Cylinder Rotation and Material Agitation The drum is a rotating cylinder slightly inclined to the horizontal (typically  1° to 5 °), with a rotational speed generally between 2 to 6 r/min The interior walls are welded with staggered lifting flights (or lifters). As the cylinder rotates, these flights continuously lift and shower the material, creating a uniform "curtain" inside the drum. This significantly maximizes the contact surface area between the material and the hot airflow.

3. Heat Exchange and Drying As the material moves from the higher end toward the lower end of the cylinder, it undergoes thorough heat exchange with the opposing (or parallel) hot airflow. The moisture within the material is heated, evaporated, and subsequently carried away by the air stream.

4. Discharge of Dried Products The dried material is discharged from the lower end of the cylinder and transported out via belt or screw conveyors. The exhaust gas, carrying water vapor, is processed through dust collection equipment (such as cyclone separators or bag filters) before being released.

4.Advantages

•  High Processing Capacity and Efficiency:Rotary dryers utilize a continuous operation model, offering large production capacities and high operational flexibility. They are particularly suitable for processing bulk granular or lumpy materials—such as ammonium sulfate, compound fertilizers, oilseeds, and chemical raw materials—meeting the demands of large-scale industrial production.

• Simple Structure, Reliable Operation, and Long Service Life:The equipment features a robust mechanical structure and a straightforward operating principle. With proper maintenance, these units can operate continuously and stably for decades, making them a globally recognized high-reliability drying solution in the industrial sector.

• Strong Adaptability and High Customization:The system can be flexibly adjusted based on specific material characteristics (such as moisture content, stickiness, and heat sensitivity) and process requirements. Variables such as drum inclination, rotational speed, lifting flight configuration, and airflow direction (co-current or counter-current) can be optimized. It can even be integrated into multi-stage combined systems for specialized designs.
• Superior Drying Uniformity:The lifting flights or tube bundles inside the drum ensure that material is continuously lifted and showered during rotation. This maximizes contact with the thermal medium, resulting in high heat and mass transfer efficiency and ensuring that the final product is dried uniformly.

• Energy Saving and Environmental Potential:Modern rotary dryers can be equipped with multi-stage waste heat recovery systems, significantly increasing thermal efficiency (with some units achieving a thermal utilization rate of ≥75%). They are also designed to effectively control dust emissions, aligning with current green and low-carbon industrial trends.

5.Technical Specifications

6.Our Solutions