Common vanadium salts and compounds: solubility and recovery technologies
Vanadium in water is best described by its dissolved chemical species, not by a single “common salt.” In oxygenated natural fresh waters, dissolved vanadium is generally present as vanadium(V) vanadate oxyanions. Sodium and ammonium vanadates are more often associated with industrial reagents, leach solutions and recovery products. The species present depend on pH, redox conditions, concentration and the other dissolved constituents.
Vanadium forms in natural and industrial waters
In water, salts dissociate and vanadium species re-equilibrate. The compounds listed below are representative of particular settings; they should not be read as a list of salts that occur everywhere.
| Water or process stream | Vanadium forms that may be relevant | Context |
|---|---|---|
| Oxic groundwater and surface freshwater | Vanadium(V) vanadate oxyanions, including H2VO4− and HVO42− | These dissolved species commonly dominate in oxic fresh waters around pH 5–9. Their distribution depends on pH and water chemistry; they are not intact sodium, calcium or magnesium “salt” molecules. |
| Mine drainage, tailings seepage and runoff | Often dissolved vanadate under oxic conditions; vanadium may also associate with iron (hydr)oxides, suspended solids or natural organic matter | Occurrence and mobility depend on ore and waste mineralogy, pH, redox conditions and weathering. Site-specific water analyses are needed. |
| Seawater and saline natural waters | Dissolved vanadate species and, depending on concentration and conditions, associated or polymeric forms | High ionic strength and co-occurring ions affect speciation. Natural salinity alone does not imply that discrete sodium or calcium vanadate salts are present as solids. |
| Salt-roast and water-leach circuits | Soluble sodium vanadates, including sodium metavanadate, in the leach liquor | In some commercial routes, vanadium-bearing feed is roasted with sodium salts; the resulting vanadates are leached into water. |
| Purification and precipitation circuits | Ammonium vanadates, including ammonium metavanadate or polyvanadate precipitates | These are recovery intermediates formed under controlled process conditions, not typical constituents of natural water. |
| Acidic, reducing process liquors | Vanadium(IV) species such as vanadyl; vanadyl sulfate may be used or present in selected process solutions | Presence depends on redox state and solution composition. Low pH by itself does not prove that vanadium is exclusively V(IV). |
Vanadium chlorides are not listed as common dissolved forms here: in aqueous streams, vanadium chemistry is better described in terms of oxygen-containing ions and the actual acidity, chloride concentration and redox conditions.
Common vanadium salts and compounds
Selected reference solubilities from published compilations are shown below. They describe individual compounds in water at the stated conditions; they are not design limits or predictions of how a mixed industrial brine will behave. Reported data can differ with temperature, hydration state, pH and source. In a real process stream, the added salt dissociates and vanadium species may re-equilibrate.
| Compound | Formula | Vanadium state | Reported water solubility | Common context |
|---|---|---|---|---|
| Sodium metavanadate | NaVO3 | V(V) | About 211 g/L at 20–25 °C | Soluble intermediate in roast–leach processing of vanadium-bearing materials |
| Sodium orthovanadate | Na3VO4 | V(V) | About 100 g/L in one published compilation at 20–25 °C; other sources describe it as soluble | Vanadate reagent and possible dissolved form in alkaline process solutions |
| Ammonium metavanadate | NH4VO3 | V(V) | Slightly soluble in cold water; more soluble in hot water. Reported values vary with source and conditions. | Precipitated intermediate used in some vanadium recovery routes |
| Vanadium pentoxide | V2O5 | V(V) | About 8 g/L at 20–25 °C; solubility increases in acid or alkali | Important product and precursor; an oxide, not a salt |
| Vanadyl sulfate | VOSO4 | V(IV) | Very soluble in water; the precise value depends on hydration state and source. | V(IV) compound used in selected chemical and redox-process solutions |
| Ammonium polyvanadates | Variable composition | Usually V(V) | No single value: composition and dissolution depend on pH and preparation | Vanadium-rich precipitates or intermediates formed during recovery |
Sodium sulfate and ammonium sulfate can occur as background salts or process reagents in some circuits. They are not vanadium compounds; if salt recovery is considered, their crystallisation and separation from vanadium-bearing solids or liquors must be evaluated separately.
Removal and concentration technologies
Mining and processing projects may need to remove vanadium from seepage or wastewater, recover it from a concentrated process liquor, or do both in separate stages. Selection depends on vanadium speciation and concentration, pH, redox potential, salinity, competing ions, solids and the required final water or product quality. Reported removal percentages from individual studies are not universal design guarantees.
| Water or process challenge | Potential approach | Important considerations |
|---|---|---|
| Dilute dissolved vanadate in mine or groundwater | Iron (hydr)oxide adsorption media or ferric coagulation followed by solids separation | Field and laboratory studies report effective removal in specific waters. Check breakthrough, competing ions, spent media or sludge and disposal requirements. |
| Vanadate with competing dissolved anions | Anion exchange, where resin selectivity and regeneration are suitable | Sulfate, phosphate and other anions can compete; regenerant becomes a vanadium-bearing residual. |
| Concentrated vanadium-bearing solution | Selective purification or solvent extraction, followed by controlled vanadate precipitation | Route selection depends on acidity, co-dissolved metals and salts. Laboratory or pilot testing can establish recovery and product quality. |
| Vanadium recovery from purified liquor | Precipitation of an ammonium vanadate intermediate and calcination to V2O5 | A common industrial route, but reagents, precipitation conditions and product specification depend on the feed and plant process. |
Membranes in high-salinity streams
Membranes can be part of an integrated treatment train, but they perform different jobs. Microfiltration and ultrafiltration remove suspended solids and floc; they do not remove dissolved vanadate. Nanofiltration or reverse osmosis may reject or concentrate dissolved ions when membrane type, pH, ionic strength, osmotic pressure and scaling risk permit. A high-salinity stream may require a high-pressure configuration or a later thermal step, but there is no universal salinity threshold at which one design is suitable.
Electrodialysis transfers ions through ion-exchange membranes; its selectivity and vanadium recovery need to be demonstrated for the actual mixture. Membrane distillation, evaporation and crystallisation can support additional water recovery or salt concentration, but do not by themselves guarantee selective vanadium recovery. Manage the resulting concentrate, spent media, sludge and crystals as part of the process design.
Discuss a vanadium-bearing water or process stream
Tell Lenntech about the water composition and whether the objective is vanadium removal, water reuse or recovery. Discuss a water-treatment challenge
Contact Lenntech at info@lenntech.com.
Last reviewed: 8 November 2026 by Lenntech.
Sources and further reading
- WHO/IPCS: Vanadium pentoxide and other inorganic vanadium compounds — selected properties and solubility data.
- U.S. EPA: Toxicological Review of Vanadium Pentoxide (2011).
- Vanitec: Making vanadium — roast–leach and vanadate recovery routes.
- Vanadium removal from mining ditch water using commercial iron products and ferric treatment residuals.
- Review: Removal techniques for vanadium from water.
- Government of Canada: Screening Assessment for Vanadium-containing substances.
- Review: Membrane technologies for saline wastewater treatment.