Henan Hongke Heavy Machinery Co., Ltd. has delivered a 200,000-ton-per-year zinc oxide (ZnO) rotary kiln production line to a customer in Tianjin, China. The line processes zinc-bearing industrial residues through carbothermic reduction and re-oxidation to recover zinc oxide.
This article covers the full project: customer background, the original problem, equipment configuration, delivery timeline, commissioning results, and customer feedback.
1. Customer Background
Location: Tianjin, China
Industry: Non-ferrous metals / secondary zinc recovery
Tianjin is a major industrial port city in northern China, with a strong metallurgical and chemical sector. The region’s steel mills and galvanizing operations generate significant volumes of zinc-bearing residues—steel mill dust, galvanizing ash, and similar byproducts—that require processing.
Our customer operates a zinc recovery facility in Tianjin. They process zinc-bearing industrial residues to recover zinc in the form of zinc oxide, which is sold to the rubber, ceramics, paint, and chemical industries. The target capacity for this project was 200,000 tons per year of ZnO product.
2. The Original Problem
Before approaching Henan Hongke Machinery, the customer faced several operational constraints:
| Problem | Impact |
|---|---|
| Variable zinc recovery rate | Zinc lost in slag; lower revenue per ton of feed |
| Unstable reduction temperature | Incomplete reduction; inconsistent ZnO grade |
| Ring formation in the kiln | Material sticking to walls; unplanned stoppages |
| High fuel consumption | Rising cost per ton of ZnO produced |
| Off-gas treatment limitations | Difficulty capturing ZnO fume and meeting emission limits |
| Throughput ceiling | Unable to accept larger volumes of feedstock |
The customer needed a purpose-built line that could handle variable feed, hold stable reduction conditions, and deliver consistent ZnO product at scale.
3. Why the Customer Chose Henan Hongke Machinery
After evaluating several suppliers, the customer selected us for specific, practical reasons:
a) Process discussion, not just equipment quotation
ZnO recovery via carbothermic reduction depends on the interaction of feed preparation, reduction temperature, kiln atmosphere, gas velocity, and fume collection. We discussed these parameters in detail during technical exchange—not just dimensions and price.
b) Design for variable feed material
The customer’s feedstock was not a uniform ore. It was a mix of industrial residues with variable zinc content and particle size. Our engineering team designed the kiln and control system around this variability.
c) Complete line responsibility
We supplied the full scope: feed preparation, the rotary kiln, burner system, oxidation settling chamber, cooling system, bag filter, slag quench system, and PLC controls. The customer did not have to coordinate multiple suppliers.
d) Proven configuration for large-capacity ZnO recovery
The 200,000 TPY capacity corresponds to a Φ3.2×60m zinc oxide rotary kiln configuration, a well-established design for industrial-scale zinc recovery .
e) Factory inspection and reference review
The customer reviewed our manufacturing facility and similar kiln projects before signing.
4. Equipment Configuration
The delivered line is built around a Φ3.2×60m rotary kiln.
| Parameter | Specification |
|---|---|
| Kiln diameter | 3.2 m |
| Kiln length | 60 m |
| Application | Zinc oxide recovery from zinc-bearing residues |
| Design capacity | 200,000 TPY ZnO |
| Kiln slope | 3–4% |
| Rotation speed | Variable frequency drive |
| Operating temperature | Up to 1,100–1,200°C (reduction zone) |
| Drive system | Heavy-duty gear drive with main and auxiliary motors |
| Sealing | Labyrinth seals with air purge at head and tail |
Scope of supply:
| System | Function |
|---|---|
| Feed preparation | Crushing, mixing with carbon reductant, pelletizing |
| Φ3.2×60m rotary kiln | Reduction and volatilization of zinc |
| Multi-channel burner | Heat input, flame control |
| Oxidation settling chamber | Controlled re-oxidation of zinc vapor to ZnO |
| Surface cooling system | Gas cooling ahead of filtration |
| Pulse-jet bag filter | ZnO fume collection |
| Slag quench system | Slag cooling and discharge |
| PLC control system | Temperature, feed rate, speed, and emission monitoring |
5. Delivery Timeline
| Stage | Status |
|---|---|
| Technical exchange and process design | Completed |
| Manufacturing at Henan Hongke facility | Completed |
| Factory assembly and no-load testing | Completed |
| Shipment to Tianjin | Completed |
| On-site installation | Completed |
| Commissioning and hot testing | Completed |
| Handover to customer | Completed |
6. Commissioning Results
| Performance Metric | Result |
|---|---|
| Zinc recovery rate | Meeting target for feed zinc content |
| ZnO product grade | Consistent, meeting customer specifications |
| Reduction zone temperature | Stable across operating shifts |
| Ring formation | Reduced; fewer unplanned stoppages |
| Throughput | Meets agreed design capacity for 200,000 TPY |
| Emission control | Dust emissions within regulatory limits |
| Operating stability | Continuous operation achieved |
7. Customer Feedback
“The line has been running steadily since commissioning. Recovery is consistent with our feed, and the ZnO grade meets our customer requirements. The engineering team was responsive during installation and commissioning. We’re satisfied with the equipment and the support.” — Production Manager, Tianjin zinc recovery facility
8. What This Means for the Customer
| Benefit | Practical Value |
|---|---|
| Higher zinc recovery | More saleable ZnO per ton of feed |
| Consistent product grade | Stable offtake agreements |
| Lower fuel consumption | Reduced cost per ton |
| Less ring formation | Fewer unplanned stoppages |
| Environmental compliance | Meets local emission requirements |
| Full-scope supplier | Single point of responsibility |
9. Building Long-Term Partnerships
Our commitment to the Tianjin customer does not end at handover. We continue to provide:
Technical support on process optimization
Spare parts availability for critical components
Maintenance guidance and preventive maintenance planning
Support for future capacity expansion or process adjustment
About Henan Hongke Heavy Machinery Co., Ltd.
Henan Hongke Heavy Machinery Co., Ltd. (Henan Hongke Machinery) has been designing and manufacturing industrial processing equipment since 2006. Our product portfolio includes:
Rotary Kilns – for zinc oxide, lime, dolomite, metallurgy, and mineral calcination
Rotary Dryers – for sludge, sand, gypsum, biomass, and industrial materials
Ball Mills – for ore, slag, cement, and chemical grinding
Crushers – for primary and secondary size reduction
We focus on one-stop solutions for mining and materials processing—complete systems, not just individual machines.
Let’s Talk About Your Zinc Recovery Project
If you process zinc-bearing residues, steel mill dust, or similar feed materials, we can discuss kiln sizing, process configuration, and expected recovery performance based on your actual material data.
Contact Henan Hongke Heavy Machinery Co., Ltd.
Henan Hongke Heavy Machinery Co., Ltd.
Rotary Kilns | Rotary Dryers | Ball Mills | Crushers – Built for Reliability, Backed by Service