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A large chrome ore concentrator in South Africa originally had an annual processing capacity of 360,000 tons. Over time, the efficiency of the original gravity separation process declined, resulting in reduced capacity, low concentrate grades, and significant resource waste.
To address these issues, the plant owner decided to upgrade the concentrator and entrusted Xinhai Mining with the task.
Xinhai Mining successfully delivered three major breakthroughs through a full-process technological upgrade:
·Capacity increase: Annual processing capacity was increased to 480,000 tons — a 33% improvement;
·Grade enhancement: The application of strong magnetic separation technology significantly improved the grade of chrome concentrate;
·Platinum and palladium recovery: Tailings from the chrome beneficiation process were further processed using flotation technology, unlocking a new profit channel.
So, how did Xinhai achieve these three breakthroughs? What does the detailed process flow look like? Read on to find out.
Project Highlights:
·Dual feed sources: Simultaneous processing of underground ore and historical tailings stored in legacy tailings ponds;
·Zero-waste utilization: Tailings are comprehensively reused, achieving a 100% resource utilization rate — a benchmark for green mining;
·Precious metal recovery: The flotation recovery of platinum and palladium from chrome tailings represents an innovative practice in the chrome beneficiation industry.
Xinhai provided complete services for this project, including process design, equipment manufacturing, installation, and commissioning. The ore processed in this project consists of two sources: raw ore from underground mining and tailings stored in the existing tailings pond. The process flow designed by Xinhai is as follows:
• Crushing and Screening System:
The raw ore is first crushed by a jaw crusher and screened using a circular vibrating screen. The oversize material is sent to manual sorting, where hand-selected concentrate is transported by a belt conveyor to storage. The undersize material is transferred to the fine ore bin, while manually rejected waste is hauled to the tailings pond.
• Grinding and Magnetic Separation System:
The ore in the fine ore bin undergoes weak magnetic removal, followed by three-stage strong magnetic separation (roughing, cleaning, and scavenging) using a vertical ring high-gradient magnetic separator.
The concentrate from the cleaning stage is thickened and dewatered.
The tailings from all three stages are thickened and discharged.
The scavenger concentrate is returned to the cleaner circuit, forming a closed loop.
• Chrome Concentrate Dewatering System:
The magnetic separation concentrate is dewatered using a combination of an inclined plate thickener and a belt filter. The final moisture content is below 15%, and the dewatered product is conveyed to the concentrate storage.
• Magnetic Tailings Regrinding System:
The magnetic tailings are thickened, and the underflow is classified by a hydrocyclone.
The cyclone underflow is fed by gravity into a ball mill for regrinding.
The ball mill discharge flows by gravity into the cyclone feed box, forming a closed grinding-classification circuit.
The cyclone overflow is sent to the flotation plant for further beneficiation.
• Platinum and Palladium Flotation System:
The regrinding product undergoes a flotation process featuring two roughing, two scavenging, and three cleaning stages. The flotation concentrate flows by gravity into a concentrate agitation tank for temporary storage, while the flotation tailings are sent to the tailings pond.
• Flotation Concentrate Dewatering System:
The concentrate from the flotation circuit is pumped from the agitation tank to a diaphragm filter press. The filtered concentrate is conveyed to the concentrate storage pond by belt conveyor.
The historical tailings are directly pumped from the tailings pond to the magnetic separation system after scrubbing and slurry mixing. The downstream processing steps are the same as those for the underground ore.
The use of vertical ring high-gradient magnetic separators enables the efficient separation of fine-grained chrome minerals. As a result, the concentrate grade has increased by over 20%, significantly enhancing beneficiation efficiency.
In the magnetic tailings regrinding circuit, the tailings are innovatively ground to 90% passing -200 mesh, effectively liberating encapsulated precious metals. A customized flotation process—featuring two roughing, two scavenging, and three cleaning stages—combined with a composite reagent system, has increased the platinum and palladium recovery rate by more than 15% above the industry average.
Due to the high grade and favorable mineral characteristics of the ore, no bench-scale beneficiation test was conducted. Leveraging Xinhai’s proprietary beneficiation database and 3D simulation design, the project achieved successful one-time commissioning with qualified product output, significantly reducing the production cycle.
Facing the challenge of chromium–platinum–palladium polymetallic symbiotic ore, Xinhai developed an innovative “magnetic separation–dominated recovery + flotation of precious metals” collaborative process.
The design encompasses eight systems:
Magnetic separation
Flotation
Filtration
Reagent preparation
Power supply and distribution
Pipeline networks
Auxiliary facilities
Complete construction drawings provided for all systems.
Key equipment includes:
High-efficiency vertical ring magnetic separators (used in coarse, cleaning, and scavenging stages)
Energy-saving large ball mills (supporting closed-circuit grinding)
Smart diaphragm filter presses, which reduce concentrate moisture to below 15%
Zero additional civil construction: Full utilization of existing plant structures and infrastructure
Seamless integration and commissioning: 480,000 t/a system successfully commissioned in one step, minimizing downtime losses
Excellent ROI: The platinum–palladium recovery system recouped its investment in just 18 months
Conclusion
South Africa is a globally recognized mining powerhouse, with abundant chrome ore resources and numerous beneficiation plants. The successful implementation of Xinhai’s upgrade plan in this region demonstrates that our solution meets international technical standards and offers a benchmark in "Intelligent Manufacturing from China."
If your project is facing challenges such as insufficient capacity, declining recovery rates, or difficulty in recovering valuable elements from tailings, we encourage you to contact us. Together, we can unlock a new path for resource value-added and sustainable mineral development.
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