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Email：sales@rotarykilnchina.com
Henan Hongke Heavy Machinery Co., Ltd. ("Henan Hongke Machinery") is currently installing a φ1.2 × 24 m zinc oxide rotary kiln in Tianjin, China. Major mechanical installation milestones are already completed, and the system is on track for commissioning in the coming weeks.
The kiln processes zinc-bearing materials — zinc ore, steel mill dust, and industrial residues — through the Waelz process (carbothermic reduction and vapor-phase oxidation) to produce high-purity zinc oxide (ZnO) powder.
How It Works
1.Zinc-bearing feedstock is mixed with coke reductant and pelletized
2.Pellets enter the inclined rotating kiln and pass through preheating, reduction, and high-temperature zones (1,100–1,200 °C)
3.Zinc is reduced to metallic vapor, then re-oxidizes in the gas phase to form fine ZnO particles
4.ZnO fume is collected via settling chamber → surface cooler → bag filter
5.Clean ZnO product is weighed and packaged
Zinc recovery: > 95%. Product purity: ≥ 99.5%.
Equipment Specification
| Parameter | Specification |
|---|---|
| Shell size | φ1.2 × 24 m |
| Shell material | Q345B carbon steel, 12–16 mm |
| Rotational speed | 0.5–2.5 rpm (VFD) |
| Inclination | 3–4% |
| Capacity | 8–15 t/h feed |
| High-temp zone | 1,100–1,200 °C |
| Drive motor | 22 kW |
Complete System Includes
| Subsystem | Function |
|---|---|
| Batching & proportioning | Precise mixing of feedstock with coke |
| Pelletizing | Disc pelletizer producing 8–15 mm pellets |
| Rotary kiln | Main reduction and volatilization reactor |
| Slag water quench | Rapid cooling of discharged slag |
| Oxidation settling chamber | Heavy particle settling; Zn oxidation completion |
| Surface cooler | Gas cooling below 160 °C |
| Bag filter | Pulse-jet collection of fine ZnO product |
| Flue gas desulfurization | Wet scrubber for SO₂ removal |
| Product packaging | Weighing and bagging of finished ZnO |
Installation Progress
Completed:
All civil foundations verified
Kiln shell sections aligned, welded, and inspected
Support stations (tires, trunnion rollers, thrust rollers) installed
Girth gear and pinion meshed; motor and reducer aligned
Kiln head and tail seals fitted
Settling chamber, surface cooler, and slag quench system erected
In progress:
Bag filter — housing erected, filter bags being installed
Ductwork — nearing completion
Scrubber tower — structure erected, packing and spray system underway
Electrical — cable tray and pulling in progress
Pelletizing system — being positioned and connected
Upcoming:
Final connections and sealing
Electrical terminations and instrument calibration
Cold and hot commissioning
Performance guarantee test run
Design Highlights
Optimized high-temperature zone — 8–10 m of the 24 m kiln length dedicated to the reduction zone, ensuring complete zinc volatilization at design capacity.
Deep-pocket internal lifters — optimized for dense pelletized feed (1.5–2.0 t/m³), ensuring uniform heat exposure and preventing material short-circuiting.
Negative pressure operation — slight vacuum at the feed end draws zinc-laden gas toward the collection system and prevents gas leakage at both ends.
Integrated gas treatment train — settling chamber → cooler → bag filter → scrubber — each stage performing a specific separation or cleaning function for maximum ZnO recovery and emission compliance.
Feedstock and Product
Feedstock
| Material | Zinc Content |
|---|---|
| Zinc oxide ore | 15–30% Zn |
| Steel mill dust (EAF dust, BF sludge) | 15–40% Zn |
| Zinc calcine / concentrates | 30–55% Zn |
| Industrial residues | Variable |
Coke-to-ore ratio: 0.30–0.35:1, pelletized before kiln entry.
Product Quality
| Parameter | Value |
|---|---|
| ZnO content (dry basis) | ≥ 99.5% |
| Metallic zinc | 0% |
| PbO | ≤ 0.05% |
| Loss on ignition | ≤ 0.2% |
| Residue on 45 μm sieve | ≤ 0.15% |
Suitable for rubber, ceramics, chemicals, animal feed, and zinc fertilizer.
Environmental Systems
| System | Performance |
|---|---|
| Bag filter | Stack dust ≤ 30 mg/Nm³ |
| Wet scrubber | Stack SO₂ ≤ 400 mg/Nm³ |
| Slag water quench | Zero process water discharge |
| Sealed transfer points | Minimal fugitive emissions |
| Negative kiln pressure | No gas leakage at feed/discharge ends |
Henan Hongke Machinery's ZnO Kiln Range
| Kiln Size | Capacity | Scale |
|---|---|---|
| φ1.0 × 18 m | 3–8 t/h | Small |
| φ1.2 × 24 m | 8–15 t/h | Medium (this project) |
| φ1.6 × 32 m | 15–25 t/h | Medium-large |
| φ2.0 × 40 m | 25–40 t/h | Large industrial |
| φ2.5 × 50 m | 40–60 t/h | Major facility |
Every system is engineered for the client's specific feedstock, capacity, and product requirements — supplied as a complete turnkey production line.
About Henan Hongke Machinery
Henan Hongke Heavy Machinery Co., Ltd., based in Henan Province, China, manufactures rotary kiln systems for zinc oxide, cement, lime, and metallurgical applications. Complete in-house manufacturing — shell fabrication, gear machining, system assembly — with global shipping, installation supervision, and after-sales support.
