1. Product Overview

Rotary dryers are widely used in building materials, metallurgy, chemical engineering, and mineral processing industries. They are suitable for drying blast‑furnace slag, clay, quartz stone, pulverised coal, sand, limestone, and other bulk materials. In metal ore processing plants, they are used for drying various metal concentrates; in steel mills, they dry cleaned coal, fluorite, iron oxide scale, etc. The operating temperature generally ranges from 400 °C to 800 °C.

Key advantages: large processing capacity, stable operation, low energy consumption, easy operation, and strong adaptability to different materials.

2. Structure and Working Principle

2.1 Equipment Structure

The rotary dryer consists mainly of the following components:

Optional auxiliary equipment can be supplied according to user requirements, including gas generators, combustion chambers, bucket elevators, belt conveyors, weigh feeders, cyclone dust collectors, induced‑draft fans, etc.

2.2 Working Principle

Wet material is fed by a belt conveyor or bucket elevator into the feed hopper, then enters the drying end through the feed pipe. The dryer shell is inclined at a slight angle to the horizontal (typically 3°–5°). Material is introduced at the higher end and moves towards the lower end under gravity as the drum rotates.

Lifting plates (flights) mounted on the inner wall of the shell lift the material and shower it down, creating a dense material curtain that comes into full contact with the hot gas stream. This maximises the heat‑transfer area and improves drying efficiency. The heating medium (hot air or flue gas) can be arranged in co‑current or counter‑current flow depending on the process requirements. As the wet material moves forward inside the drum, it receives heat directly or indirectly from the heating medium, completing the drying process. The dried material is discharged at the outlet via a belt conveyor or screw conveyor. The heating medium, after passing through the dryer, is generally cleaned by a cyclone dust collector; when necessary, a bag filter or wet scrubber can be added before final discharge.

3. Features and Advantages

3.1 Core Advantages

• Large processing capacity – continuous operation, suitable for large‑scale industrial production.
• Simple and robust construction – low failure rate, easy operation, low maintenance costs, stable performance.
• Wide range of applications – can handle powders, granules, strips, lumps, and other material forms.
• High operational flexibility – can tolerate significant fluctuations in throughput without compromising product quality.
• Strong overload resistance – low fuel consumption and low drying cost.
• Flexible process arrangement – can adopt co‑current or counter‑current drying according to different process needs.
• Adjustable operating parameters – can change rotational speed, feed rate, and air temperature to suit different materials, forming a continuous full‑cross‑section material curtain for more efficient heat and mass exchange.

3.2 Heat‑Transfer Methods

3.3 Gas‑Flow Directions

4. Detailed Technical Specifications and Models

4.1 Standard Model Parameter Table

The following table lists technical parameters for mainstream rotary dryer models:

4.2 NHH Series Rotary Dryer Specifications

4.3 KX Series Rotary Dryer Specifications

4.4 H Series Rotary Dryer Specifications

5. Selection Guide

5.1 Key Factors for Selection

1. Material properties – initial moisture content, final moisture requirement, bulk density, particle size and size distribution.
2. Throughput requirement – required capacity in tonnes per hour based on production scale.
3. Heat source availability – choose the heating method according to available fuel types (coal, natural gas, oil, electricity, etc.).
4. Process requirements – determine co‑current or counter‑current flow; direct or indirect heat transfer.
5. Site conditions – determine the maximum allowable length and footprint based on installation area.

5.2 Recommended Sizing Guide

6. Application Fields

Rotary dryers are widely used in the following industries:

• Building materials – drying slag, clay, limestone, quartz stone, etc.
• Metallurgy – drying metal concentrates, cleaned coal, fluorite, iron oxide scale, etc.
• Chemical industry – drying ammonium sulphate, sodium sulphide, ammonium nitrate, urea, oxalic acid, potassium dichromate, PVC, compound fertilisers, etc.
• Mineral processing – drying various metallic and non‑metallic concentrates.
• Food industry – drying glucose, table salt, granulated sugar, vitamins, etc.

7. Ordering Instructions

1. Please provide the material name, bulk density, initial moisture content, required final moisture, and expected throughput.
2. Please specify the heat source type (coal, natural gas, oil, electricity) and available fuel conditions.
3. Non‑standard models can be custom‑made, including shell length, liner material, lifting plate design, etc.
4. Complete auxiliary systems such as gas generators, combustion chambers, dust collection systems, and conveying systems can be supplied as a package.
5. The shell length can be optimised based on initial and final moisture requirements.