As the global share of wind and solar power in electricity systems rapidly approaches 50%, the demand for long-duration, large-scale, and high-safety energy storage technologies is becoming increasingly urgent. Vanadium redox flow batteries (VRFBs), with their intrinsic safety, exceptionally long service life, and flexible configuration capabilities, are emerging as a key technology for integrating renewable energy and stabilizing the grid. Against this backdrop, the strategic importance of vanadium has significantly increased.

Vanadium-bearing stone coal resources are widely distributed worldwide but are generally characterized by low grade and difficult vanadium extraction, and they remain largely underdeveloped. Among various vanadium extraction processes, the acid leaching–solvent extraction method is gradually becoming the mainstream technology for vanadium recovery from leach solutions due to its high selectivity, high extraction efficiency, and controllable process. In the extraction step, Zhengzhou Tiei’s CWL-M series centrifugal extractor provides outstanding separation performance, offering a reliable solution for the economic and efficient development of low-grade vanadium stone coal.

Process Challenges in Vanadium Extraction from Stone Coal

Vanadium in stone coal typically occurs in isomorphous forms within silicate minerals such as mica and illite, requiring roasting and acid leaching to transfer vanadium into the liquid phase. The resulting leach solution is complex and often contains multiple impurity ions, including iron, aluminum, phosphorus, and chromium. Traditional precipitation and ion exchange methods often suffer from low recovery rates or incomplete impurity separation, making them insufficient for producing high-purity vanadium products.

The solvent extraction method, using highly selective extractants, can preferentially extract vanadium from complex multi-metal systems and obtain a purified vanadium solution through stripping. The core challenge of this process lies in achieving rapid and complete separation after the two phases are contacted.

CWL-M Centrifugal Extractor: Core Equipment for Vanadium Recovery from Stone Coal Leach Solutions

To address the challenges of stone coal leach solutions—namely “low vanadium concentration, high impurity content, and easy emulsification”—Zhengzhou Tiei’s CWL-M series centrifugal extractor has been systematically optimized in both structural design and operational logic. They have demonstrated significant advantages in multiple industrial vanadium recovery projects.

Process Flow of Vanadium Recovery from Stone Coal Leach Solutions

1.Acid Leaching and Pretreatment: Stone coal is roasted and leached with sulfuric acid to produce vanadium-containing leach solution, which is then pretreated through reduction, pH adjustment, and other steps.
2.Multi-Stage Countercurrent Extraction: The leach solution and organic phase containing the extractant simultaneously enter the CWL-M centrifugal extractor, where mixing and rapid phase separation occur in the high-speed rotating drum. The vanadium-rich organic phase proceeds to the next stage, while the raffinate (vanadium-depleted aqueous phase) is discharged or recycled.
3.Washing and Impurity Removal: The loaded organic phase enters the washing section, where dilute acid or pure water removes co-extracted impurities such as iron, chromium, and phosphorus.
4.Stripping: The washed organic phase contacts a stripping agent (e.g., dilute sulfuric acid) in the centrifugal extractor, transferring vanadium back into the aqueous phase to obtain a purified vanadium-rich solution.
5.Vanadium Precipitation and Calcination: The vanadium-rich solution undergoes ammonium precipitation and calcination to produce vanadium pentoxide (V₂O₅) as the final product.

Throughout the process, the CWL-M centrifugal extractor performs three critical separation tasks—extraction, washing, and stripping—directly determining vanadium recovery efficiency and product purity.

Why Choose the CWL-M Centrifugal Extractor?

Compared with traditional mixer-settlers, extraction columns, and other equipment, the CWL-M centrifugal extractor offers significant advantages in the vanadium recovery from stone coal:

1.High-Efficiency Separation, Effectively Eliminating Emulsification
Stone coal leach solutions often contain silica colloids and fine solid particles, which readily form emulsions at the liquid–liquid interface, causing difficult phase separation and high organic phase loss in conventional equipment. The CWL-M centrifugal extractor generates a centrifugal field of 500–900 g, achieving instantaneous forced separation after phase contact. This effectively eliminates emulsification and entrainment, dramatically reducing organic phase loss.
2.Multi-Stage Countercurrent, Extraction Efficiency over 98%
The equipment can be flexibly configured as a multi-stage countercurrent extraction system, with stage efficiency exceeding 95%. For low-grade stone coal leach solutions (vanadium concentration 1–5 g/L), 3–4 stages of countercurrent extraction can achieve over 98% vanadium recovery, significantly improving resource utilization.
3.Selective Separation, Thorough Impurity Removal
By adjusting rotor speed, phase flow ratios, and residence time, the extraction process can be precisely controlled for selectivity. In the separation of vanadium from chromium, phosphorus, and iron, the CWL-M centrifugal extractor can achieve impurity removal rates above 99%, providing a high-purity solution for subsequent vanadium precipitation and ensuring vanadium pentoxide (V₂O₅) meets industrial-grade standards above 99.5%.
4.Fully Enclosed Design, Safe and Environmentally Friendly
The fully enclosed structure minimizes organic phase volatilization, provides a safer and cleaner working environment, and significantly reduces fire and explosion risks, meeting the strict safety and environmental requirements of modern chemical industries.
5.Automated Operation, Suitable for Continuous Large-Scale Production
The CWL-M centrifugal extractor starts quickly, operates smoothly, and supports DCS remote control and unattended operation. Its compact structure and small footprint allow handling capacities from laboratory scale to several hundred cubic meters per hour, providing a reliable solution for large-scale industrial applications.

With the large-scale deployment of vanadium redox flow batteries in the energy storage sector, the market demand for high-quality vanadium products will continue to grow. The world’s abundant vanadium-bearing stone coal resources, once the technical bottlenecks of low grade and difficult extraction are overcome, will become a key foundation for securing vanadium supply. As a critical piece of equipment in the acid leach–vanadium extraction process, the CWL-M centrifugal extractor is helping the stone coal vanadium industry transition from “high cost, low efficiency” to “economical and large-scale” with its efficient, stable, and automated performance.

If you are seeking an efficient solution for the development and utilization of low-grade vanadium stone coal, we welcome you to contact us. Zhengzhou Tiei Extraction—specializing in liquid–liquid centrifugal extraction technology for over a decade—provides a one-stop solution for vanadium recovery, from laboratory validation to equipment selection, and from installation and commissioning to personnel training.
Email: sales@tieiextraction.com
Whatsapp: +86 19069612820