Hydrometallurgical solvent extraction of chromium from chromium slag is currently one of the commonly used methods. During chromite mining, chromium slag is the main type of industrial solid waste, which poses significant environmental hazards. Therefore, how to extract and separate chromium from chromium slag to achieve resource recovery and reuse while reducing environmental pollution has become the primary challenge in chromium slag treatment. Extensive experiments have shown that by using the CWL-M series centrifugal extractor developed by Tiei Extraction, with 1-octyl-3-methylimidazolium tetrafluoroborate ionic liquid as the extractant and pentanol as the diluent, chromium can be effectively extracted and separated from chromium slag.
At present, the main methods for extracting and separating chromium from chromium slag include the precipitation method, adsorption method, ion-exchange resin method, and solvent extraction method. Among them, traditional methods such as precipitation, adsorption, and ion-exchange resins have the advantage of simple operation, but they generate large amounts of wastewater during production, require extensive pollutant treatment, and are prone to secondary pollution. In contrast, the solvent extraction method demonstrates greater advantages in efficiency and environmental sustainability.
Process Flow of Chromium Extraction from Chromium Slag by Centrifugal Extractor
Extraction Stage
First, pentanol is used as the solvent to prepare the organic phase with a certain concentration of extractant. The organic phase and the feed solution, i.e., the acid leachate of chromium slag, are then injected into the centrifugal extractor at a defined ratio. Driven by the rotation of the drum, the turbine disc and impeller rapidly mix and disperse the two phases, allowing sufficient mass transfer between them and completing the mixing and extraction process. The mixed solution is then separated into two phases under the action of centrifugal force and discharged from the machine.
Stripping Stage
After the extraction stage, the organic phase loaded with chromium needs to undergo stripping to recover and recycle the solvent. The loaded organic phase and the stripping solution enter the centrifugal extractor, where chromium is separated from the solvent through the back-extraction process, enabling solvent recovery and reuse.
Advantages of CWL-M Centrifugal Extractor in Chromium Slag Extraction
1.High efficiency and large throughput
The centrifugal extractor can handle 1–150 m³ per hour, delivering excellent separation performance. Even for materials with a very small density difference, it achieves efficient extraction and phase separation.
2.High degree of automation for continuous extraction
In hydrometallurgical production lines, multiple units are often connected in series. The CWL-M extractor offers a high level of automation, enabling more accurate monitoring of key process data and easier operation and management.
3.Energy-saving design
Under the same processing capacity, its power consumption is only 1/10 to 1/3 of that of traditional annular type, making it much more energy-efficient.
4.Excellent corrosion resistance
The equipment can be manufactured with perfluoropolymer materials, which provide strong resistance against corrosion from concentrated acids (such as hydrochloric acid and mixed acids).
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Email: sales@tieiextraction.com
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