P350 Neutral Organophosphorus Tungsten Extractant
Application Scope
P350 (Dimethylheptyl Methyl Phosphate) is a high-stability neutral organophosphorus extractant designed for tungsten, molybdenum and vanadium hydrometallurgy applications. Its main industrial value is concentrated in selective separation and purification processes where high metal selectivity and stable long-term operation are required.
In tungsten processing, P350 is widely applied for tungsten-molybdenum separation from acidic leach solutions. It provides strong extraction affinity for tungsten species while reducing molybdenum co-extraction, helping improve tungsten solution purity and supporting the production of high-grade ammonium paratungstate (APT) and tungsten salt products.
P350 is also used in vanadium recovery processes from acidic mineral solutions and industrial residues. Its selective extraction performance enables efficient vanadium enrichment and separation from complex solution systems. In tungsten salt purification circuits, P350 assists in removing trace impurities to improve product quality for industrial and high-purity tungsten chemical production.
As secondary applications, P350 can support fine purification of scattered metals such as gallium, germanium, indium and rhenium from specific metallurgical by-product streams. These applications are generally focused on refining and purification rather than large-scale primary extraction.
Mechanism
P350 works through a neutral organophosphorus solvent extraction mechanism. The phosphorus-oxygen functional group coordinates with target metal ions under acidic conditions, forming stable neutral complexes that can be transferred into the organic phase.
Unlike ionic extractants, P350 relies on molecular solvation and coordination selectivity for metal separation. Its stable molecular structure provides good chemical resistance and maintains extraction performance during continuous hydrometallurgical operation under acidic and elevated temperature conditions.
The selective coordination characteristics of P350 allow efficient separation of tungsten, molybdenum and vanadium from impurity ions, supporting improved process stability and solution purification efficiency.
Physicochemical Properties
P350 is a neutral organophosphorus extractant with high chemical stability, low water solubility and excellent fluidity characteristics. These properties reduce reagent loss during solvent extraction operation and support stable industrial circulation.
Specifications
| Parameter | Specification |
|---|---|
| CAS Number | 3245-24-5 |
| Chemical Name | Dimethylheptyl Methyl Phosphate |
| Active Content | ≥75% |
| Appearance | Yellow non-volatile oily liquid |
| Molecular Weight | 320 |
| Specific Gravity | 0.913–0.915 |
| Viscosity | 7–8 mPa·s |
| Refractive Index | 1.4350–1.4360 |
| Flash Point | 165 ℃ (open cup) |
| Boiling Point | 140–145 ℃ (2mmHg) |
| Pour Point | <-70 ℃ |
| Water Solubility | <10 mg/L |
| Thermal Stability | Stable after 168 hours continuous reaction in 1M kerosene and 6N nitric acid at 80 ℃ |
Storage & Handling
P350 should be stored in cool, dry and well-ventilated warehouses away from direct sunlight, high temperature and strong oxidizing agents. Containers should remain tightly sealed to prevent contamination and maintain product stability.
During operation and transportation, avoid strong impact and direct contact with skin or eyes. Appropriate personal protective equipment, including chemical-resistant gloves and safety goggles, should be used according to industrial chemical handling requirements.
Advantages / Limitations
Advantages
High selectivity for tungsten, molybdenum and vanadium separation processes.
Excellent chemical and thermal stability for continuous hydrometallurgical operation.
Low water solubility reduces organic phase loss and improves process economy.
Good low-temperature fluidity due to extremely low pour point characteristics.
Suitable for tungsten solution purification and strategic mineral refining applications.
Limitations
Mainly specialized for tungsten, molybdenum and vanadium hydrometallurgy rather than general base metal extraction.
Secondary applications in scattered metals are mainly focused on fine purification processes.
Process performance depends on solution acidity, metal concentration and extraction circuit design.
Summary
P350 is a high-performance neutral organophosphorus extractant developed for tungsten, molybdenum and vanadium hydrometallurgy. With strong selectivity, chemical stability and low reagent loss characteristics, it is widely applied in tungsten-molybdenum separation, vanadium recovery and tungsten solution purification.
For mining and metallurgical operations requiring stable solvent extraction performance, P350 provides a reliable reagent solution for strategic mineral processing, supporting improved solution quality, process efficiency and long-cycle production stability.
P350 Neutral Organophosphorus Tungsten Extractant – FAQ
Q1. How is P350 extractant applied for removing molybdenum, arsenic, and phosphorus impurities from ammonium tungstate solutions?
P350 Neutral Organophosphorus Tungsten Extractant can be applied in tungsten hydrometallurgical purification processes where selective separation of impurity elements is required. In ammonium tungstate solutions, process conditions such as acidity, phase ratio, extractant concentration, and contact time should be optimized according to the impurity composition. P350 is mainly evaluated for its extraction selectivity toward targeted metal species, while controlling co-extraction of valuable tungsten. Laboratory shake tests and pilot-scale continuous extraction trials are commonly used to determine suitable operating parameters before industrial implementation.
Q2. What pH adjustment is required when using P350 for tungsten solutions containing high calcium and magnesium impurities?
For tungsten solutions with high calcium and magnesium content, pH adjustment and solution conditioning may be required before P350 extraction. Excessive alkaline earth metal ions can influence phase behavior, impurity distribution, and extraction efficiency depending on the solution chemistry. Pre-treatment steps such as impurity removal, filtration, or chemical conditioning may improve extraction stability. The optimal pH range should be determined through laboratory testing based on tungsten concentration, impurity levels, and the selected extraction flow sheet.
Q3. How should the organic-to-aqueous phase ratio (O/A) be optimized when using P350 for tungsten-molybdenum separation?
The organic-to-aqueous phase ratio (O/A) is an important operating parameter affecting tungsten recovery, impurity removal efficiency, and solvent loading capacity. For tungsten-molybdenum separation using P350, the appropriate O/A ratio depends on metal concentration, extractant concentration, extraction stages, and required separation performance. A higher organic phase ratio may improve extraction capacity but can increase solvent consumption. Laboratory counter-current simulation tests are recommended to determine the optimum O/A ratio and stage configuration for each specific tungsten processing solution.
Q4. How can phase separation and emulsification risks be controlled when using P350 in continuous extraction equipment?
In continuous solvent extraction systems, phase separation performance is influenced by extractant formulation, diluent selection, aqueous impurities, mixing intensity, and equipment design. When applying P350 in mixer-settlers or extraction columns, proper control of agitation speed, settling time, interface level, and organic phase quality helps reduce emulsification risks. Pre-treatment of feed solutions to remove suspended solids and organic contaminants can also improve operational stability. Pilot testing is recommended to evaluate phase disengagement characteristics before large-scale installation.
Q5. Does temperature affect the tungsten extraction performance of P350 between 10°C and 40°C?
Temperature can influence solvent extraction performance by affecting reaction kinetics, viscosity, phase separation, and metal distribution behavior. For P350 tungsten extraction systems, moderate temperature variations may change extraction equilibrium and organic phase fluidity. In practical hydrometallurgical operations, temperature control is usually considered together with tungsten concentration, acidity, mixing conditions, and equipment efficiency. Testing at the expected operating temperature range helps determine whether process adjustments are required to maintain stable extraction and separation performance.
Q6. What stripping conditions are recommended for recovering tungsten from P350-loaded organic phase?
The stripping performance of P350-loaded organic phase depends on tungsten loading level, aqueous composition, acid concentration, stripping agent selection, and the number of stripping stages. Appropriate stripping conditions should provide efficient tungsten recovery while maintaining organic phase stability for recycling. Laboratory tests are typically conducted to evaluate tungsten transfer efficiency, phase behavior, and extractant regeneration requirements. The final stripping parameters should be integrated with the overall tungsten purification flow sheet, including downstream crystallization or precipitation processes.
Q7. Is pre-desilication required when using P350 for tungsten solutions with high silicon content?
High silicon content in tungsten leach solutions may affect solvent extraction performance by increasing viscosity, introducing colloidal species, or causing phase separation problems. Depending on silica concentration and solution characteristics, pre-treatment such as desilication, clarification, or filtration may be considered before P350 extraction. The necessity of pre-treatment should be evaluated through laboratory compatibility tests. Proper feed preparation can improve extraction stability, reduce organic contamination, and support consistent tungsten recovery in continuous solvent extraction operations.
Q8. How does P350 perform in alkaline and acidic tungsten hydrometallurgical processes?
P350 application depends on the tungsten process route, solution chemistry, and target separation objectives. Compatibility with acidic or alkaline tungsten systems should be evaluated based on tungsten species distribution, impurity composition, and extraction mechanism. Process conditions such as pH adjustment, phase composition, and stripping method may require optimization for different hydrometallurgical flowsheets. Laboratory evaluation is recommended to confirm extraction selectivity, phase stability, and recycling performance before applying P350 in industrial tungsten purification circuits.
Q9. Can P350 be used for recovering tungsten from tungsten-containing wastewater or recycling solutions?
P350 may be considered for tungsten recovery from certain industrial recycling streams or metallurgical wastewater where tungsten concentration and solution chemistry are suitable for solvent extraction. The feasibility depends on tungsten concentration, interfering ions, organic contaminants, and required recovery targets. Pre-treatment and process optimization may be necessary to improve extraction selectivity and operational stability. Laboratory testing can help determine whether P350 is suitable for integration into tungsten recovery and water recycling systems.
Q10. What are the technical advantages of using P350 compared with traditional amine extractants in tungsten hydrometallurgy?
P350 Neutral Organophosphorus Tungsten Extractant is evaluated as an alternative solvent extraction option depending on the tungsten processing conditions and separation requirements. Compared with traditional amine-based extraction systems, differences may exist in extraction behavior, selectivity, phase characteristics, and process compatibility. The actual technical and economic advantages depend on ore composition, impurity profile, reagent consumption, and plant operating conditions. A complete evaluation should include laboratory testing, pilot verification, and comparison with the existing tungsten purification process before industrial adoption.