The process and equipment for extracting vanadium from vanadium slag need to be selected by customers according to specific circumstances. The vanadium extraction-steelmaking process can achieve pre-dephosphorization while extracting vanadium from vanadium-containing molten iron to reduce the dephosphorization burden of the steelmaking process, but the vanadium slag obtained is high-calcium and high-phosphorus vanadium slag. There are different process operations for extracting vanadium from this type of vanadium slag. The main methods are: sodium roasting-water leaching vanadium extraction method, calcination roasting-acid leaching vanadium extraction method, extraction of vanadium from vanadium-containing solution by solvent extraction method, etc. The advantages and disadvantages of different processes are compared below.
1.Sodium roasting--water leaching vanadium extraction method
Main principle: Vanadium slag and sodium salt are mixed in a certain proportion, and trivalent vanadium and tetravalent vanadium contained in the vanadium slag are converted into water-soluble pentavalent vanadium (mainly in the form of sodium vanadate) under an oxidizing atmosphere.
Main process flow: Vanadium slag sodium salt mixing--roasting--water leaching--purification--vanadium precipitation--filtration and washing--drying and calcining
Advantages and disadvantages: The technology is mature and the leaching process is simple, but roasting produces corrosive gases such as HCl, CL2, SO2, SO3, and sodium salt additives will introduce sodium ions, making it difficult to continue to use the residue.
2.Calcination roasting--acid leaching vanadium extraction method
Main principle: Vanadium slag and calcium salt are mixed in a certain proportion, and V3+ and V4+ are oxidized into V5+ (mainly in the form of calcium vanadate) which is insoluble in water but soluble in acid under an oxidizing atmosphere.
Main process: Vanadium slag calcium salt mixing--roasting--acid leaching--purification--vanadium precipitation--filtration and washing--drying and calcining
Advantages and disadvantages: It avoids the generation of harmful gases, relaxes the restrictions on the calcium oxide content in vanadium slag, does not introduce sodium ions, and affects the further utilization of vanadium slag, but has high requirements for corrosion resistance of equipment.
3.Extraction of vanadium from vanadium-containing solution by solvent extraction method
Main principle: The vanadium-containing solution is injected into the CWL-M centrifugal extractor with an extractant to extract the vanadium into the organic phase, and then the stripping agent is used to strip the vanadium into the aqueous phase.
Main process: vanadium-containing solution--extraction--stripping--vanadium precipitation--washing and filtration--drying and calcining
Advantages and disadvantages: It has good separation effect, large processing capacity, high vanadium recovery rate, recyclable extractant, low production cost, product purity up to 99.9%, large initial investment, easy and stable operation, and high degree of automation.
At present, the method used to extract vanadium from vanadium slag is solvent extraction, and the equipment used is the CWL-M centrifugal extractor mentioned above. This equipment is a new type of liquid-liquid extraction and separation equipment independently developed and produced by Zhengzhou Tiei Extraction. It can be widely used in the extraction of many metal elements in the field of hydrometallurgy.
For more information about the CWL-M centrifugal extractor, welcome contact us.
Email: sales@tieiextraction.com
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