Rotary Drum Dryer
Moisture is one of the most expensive hidden costs in a mining, mineral processing or aggregate plant. Wet concentrate adds freight weight, wet sand blocks screens and silos, and wet slag cannot be ground efficiently. A rotary drum dryer solves all three problems in one continuous, high-throughput operation. Baichy Heavy Industry — a manufacturer of crushing, ore grinding and beneficiation equipment — engineers every rotary drying system around your material, not around a catalogue number.
What Is a Rotary Drum Dryer?
A rotary drum dryer is a continuous industrial dryer built around a slightly inclined, slowly rotating steel cylinder. Wet material enters the higher end; hot gas from a coal, gas, oil or biomass furnace flows through the drum. Internal lifting flights pick up the material and shower it through the gas stream, creating a dense curtain of particles. That curtain is why the rotary drum dryer is so efficient: every particle is repeatedly exposed to hot gas, so heat and mass transfer happen fast and evenly. Drum inclination (typically 3–5%) and rotation speed control residence time.
How Does a Rotary Drum Dryer Work?
The Drying Cycle Step by Step
Feeding — wet material is metered in by belt or screw feeder.
Hot gas generation — the furnace delivers 400–800 °C gas, set by the material's thermal sensitivity.
Lifting and cascading — flights scatter the material for maximum gas–solid contact.
Evaporation — heat transfers by convection, radiation and conduction; moisture vaporises into the gas.
Discharge — dried product exits via a star valve or sealed discharge hood.
Dedusting — exhaust passes a cyclone and bag filter (or wet scrubber) before the induced draft fan and stack.
Structural diagram of a single-drum dryer
Co-Current, Counter-Current and Compound Flow
• Co-current: gas and material travel the same way, so the wettest feed meets the hottest gas. Fast initial evaporation, cool product — the standard choice for sand and heat-sensitive materials.
• Counter-current: gas meets the driest material, giving the lowest residual moisture but a hotter product.
• Compound: combines both, used for sticky filter cakes and materials that ball up.
Main Components of a Rotary Drum Dryer Line
A complete Baichy line includes a hot air furnace, feed conveyor, rotary drum dryer main unit, discharge conveyor, cyclone separator, bag filter, induced draft fan, chimney and PLC control cabinet with temperature interlocks. Key mechanical parts are the shell (carbon steel, or stainless/heat-resistant steel for corrosive duty), riding rings and support rollers, thrust rollers, girth gear and pinion, lifting flights, and the end seals. Seals matter more than most buyers expect: leaking seals admit cold air, destroy thermal efficiency and overload the dust collector.
Technical Specifications of Baichy Rotary Drum Dryer
The table below lists Baichy's standard single-drum series. Capacity is on a wet basis for general mineral and aggregate feed.
| Model (Ø × L, m) | Drum Volume (m³) | Capacity (t/h) | Gradient (%) | Speed (r/min) | Max. Inlet Air Temp. (°C) | Main Motor (kW) |
|---|---|---|---|---|---|---|
| Φ1.2 × 10 | 11.3 | 2.2–3.0 | 3–5 | 3–8 | 700–800 | 7.5 |
| Φ1.5 × 12 | 21.2 | 4.5–5.7 | 3–5 | 2–6 | 700–800 | 15 |
| Φ1.8 × 14 | 35.6 | 7.6–9.5 | 3–5 | 2–6 | 700–800 | 18.5 |
| Φ2.0 × 18 | 56.5 | 8.4–12.3 | 3–5 | 1.5–6 | 700–800 | 22 |
| Φ2.2 × 18 | 68.3 | 12.8–16.2 | 3–5 | 1.5–6 | 700–800 | 22 |
| Φ2.4 × 20 | 90.4 | 19.3–24.1 | 3–5 | 1.5–5 | 700–800 | 55 |
| Φ2.6 × 24 | 127.4 | 27.2–34.0 | 3–5 | 1.5–5 | 700–800 | 75 |
| Φ3.0 × 20 | 141.3 | 30.1–37.7 | 3–5 | 1.5–5 | 700–800 | 85 |
| Φ3.2 × 25 | 201.0 | 42.9–53.6 | 3–5 | 1.5–5 | 700–800 | 110 |
Note: throughput varies with material, feed size and moisture. Figures assume typical sand or mineral feed dried to 0.5–1%; high-moisture filter cake can cut dry throughput by 20–30%. Confirm the final model by drying test.
For tight sites, Baichy also builds a three-cylinder (triple-pass) rotary drum dryer, which nests three coaxial drums in one shell, cuts installed length by about 60% and lifts thermal efficiency from roughly 35% to 45–55%.
Materials a Rotary Drum Dryer Can Handle
Sand: river sand, silica/quartz sand, foundry sand, dry-mix mortar sand
Ores and concentrates: iron, manganese, copper, lead-zinc, phosphate rock, fluorite, barite
Industrial minerals: limestone, clay, kaolin, bentonite, gypsum, feldspar, coal powder
By-products: blast furnace slag, steel slag, coal gangue, tailings, fly ash
Other bulk solids: biomass, fertilizer raw materials, sludge and filter cake
How to Select the Right Rotary Drum Dryer
1. Start with the Moisture Balance, Not the Machine Size
The most common selection error is specifying a rotary drum dryer by "t/h of product" without stating initial moisture. Drying sand from 8% to 0.5% and drying cake from 25% to 3% are entirely different thermal duties at identical dry tonnage. Always give three numbers: feed rate, initial moisture, target moisture.
2. Match Drum Volume to Evaporation Load
The real metric is kilograms of water evaporated per hour, not tonnes of feed. Once evaporation load is known, drum volume, gas volume and furnace rating follow directly.
| Selection Factor | What to Define | Typical Impact |
|---|---|---|
| Initial moisture | Wet basis, % | >15% may need a pre-breaker or recycle loop |
| Target moisture | Wet basis, % | Each extra 1% reduction adds ~8–12% heat per ton |
| Particle size & bulk density | mm, kg/m³ | Sets flight design and gas velocity |
| Abrasiveness / corrosiveness | — | Decides liner, flight and shell material |
| Heat source | Coal, gas, oil, biomass, waste heat | Sets furnace and burner design |
| Emission limit | mg/Nm³ | Cyclone + bag filter typically ≤100 mg/Nm³ |
3. Choose the Heat Source Around Local Fuel Prices
A rotary drum dryer runs on coal, natural gas, diesel, heavy oil, biomass or recovered kiln waste heat. Fuel choice is a financial decision — ask for cost per ton of dried product, not just equipment price.
4. Don't Under-Specify Dust Collection
Emission rules keep tightening. The standard two-stage setup — cyclone pre-separator plus pulse-jet bag filter — protects both your licence to operate and your product recovery.
Operating Cost, Efficiency and Maintenance
Energy dominates lifetime cost. Typical consumption is 8–15 kg of standard coal per ton of dried product, or about 3.2–4.5 MJ per kg of water evaporated. Three quick wins: insulate the shell, maintain the end seals, and recover exhaust heat for combustion air.
Maintenance is simple but must be disciplined: check roller alignment and lubrication weekly, monitor riding ring contact and gear backlash monthly, inspect flights and seals every 3–6 months. Done properly, the shell and support system runs 15+ years, with flights replaced every 2–3 years on abrasive duty.
Why Choose Baichy Heavy Industry
Because we build crushing, grinding and beneficiation equipment, a rotary drum dryer from Baichy is specified as part of your whole flowsheet. We offer free sample drying tests with a moisture-vs-time curve and model recommendation, full process design, installation and commissioning supervision, operator training and fast spare parts supply.
Rotary Drum Dryer
Frequently Asked Questions
1. What final moisture can a rotary drum dryer achieve?
For free-flowing sand and mineral feed, 0.5–1% is routine; 0.5–3% is typical for ores and concentrates. Heat-sensitive salts get separate discharge temperature control to prevent re-caking.
2. Single-drum or three-cylinder rotary drum dryer?
Pick a single-drum rotary drum dryer for maximum capacity, simplest maintenance and lowest capital cost per ton. Pick a three-cylinder unit where floor space is tight, fuel is expensive, or you dry sand and slag at 5–80 t/h and want faster payback on efficiency.
3. What heat sources can be used?
Coal, natural gas, LPG, diesel, heavy oil, biomass (wood chips, rice husk, palm shell) and kiln waste heat. The furnace and burner are engineered to the fuel available on your site.
4. How do I know which model I need?
Send feed rate, initial moisture, target moisture, particle size and fuel. Baichy runs a free drying test and returns a moisture curve plus recommended model — final sizing comes from test data, not estimates.
5. What about dust emissions and compliance?
Standard configuration is cyclone plus pulse-jet bag filter, keeping exhaust dust well below 100 mg/Nm³, with wet scrubbing available where required. Fan, ducting and stack are supplied as one complete package sized to your local standard.
Baichy Heavy Industry
Baichy Heavy Industry is a high-tech mining equipment company integrating R&D, manufacturing, sales, and after-sales service. Focusing on crushing, grinding, and mineral processing equipment, we provide professional solutions to our customers. We are ISO9001:2015 、certified, and our products include mobile crushing palnts, crawler crushing plant, construction waste crushing plants, jaw crushers, sand making machines, cone crushers, fine crushers, grinding mills, ball mills, etc., all with reliable performance to meet diverse project needs.
Baichy Heavy Industry – Your Trusted Partner
To ensure optimal performance of your equipment, Baichy Heavy Industry offers:
- Professional on-site installation guidance
- Comprehensive operator training
- 24/7 technical support & maintenance services
Our complete after-sales service system guarantees long-term, stable operation of your machinery with minimal downtime.
Protect Your Rights – Only Use Official Channels
To avoid scams and ensure authentic support, contact us exclusively through:
• Official Website: www.baichychina.com
• WhatsApp: +8615093222637
• Email: [email protected]
Your satisfaction is our priority – expect prompt, professional service every time.
(Note: Beware of unauthorized third parties claiming to represent Baichy. Always verify through official contacts.)
