N263 (TCMAC / Trioctylmethylammonium Chloride) Extractant

Application Scope

N263, also known as TCMAC or Aliquat 336, is a high-efficiency quaternary ammonium salt anion exchange extractant widely used in strategic mineral hydrometallurgy. Its core industrial applications focus on tungsten-molybdenum-vanadium separation and rhenium recovery, serving as a standard reagent for anion-complexed metal extraction and purification.

In tungsten and molybdenum processing, N263 selectively extracts tungstate and molybdate anions from acidic and weakly alkaline leach solutions, enabling efficient enrichment and graded separation of tungsten and molybdenum while reducing impurity interference. This capability supports the production of higher-purity tungsten and molybdenum intermediate products.

For vanadium hydrometallurgy, N263 provides selective vanadium enrichment and vanadium-molybdenum separation from complex metal-bearing solutions. In rhenium recovery applications, it effectively extracts perrhenate ions from copper-molybdenum smelting ash and industrial waste liquids, supporting high-value rhenium resource recycling.

As secondary applications, N263 can assist in purification and recovery of antimony, bismuth and tin from associated non-ferrous metal solutions through anion complexation extraction. It has no mature commercial application in lithium, nickel-cobalt, tantalum-niobium, fluorite, boron and magnesium processing.

Extraction Mechanism

N263 works through quaternary ammonium anion exchange and ion-pair extraction mechanisms. The positively charged ammonium group combines with negatively charged metal oxyanions and chloro-complexed ions in aqueous solutions, forming extractable neutral complexes that transfer into the organic phase.

Unlike tertiary amine extractants, N263 does not require acid protonation before operation and can maintain stable extraction performance in acidic and weakly alkaline systems. Its stable molecular structure provides high selectivity, reliable phase separation and suitability for continuous industrial extraction circuits.

Physicochemical Properties

N263 is a high-purity quaternary ammonium salt extractant with excellent chemical stability and compatibility with conventional organic diluents. Its low melting point and stable extraction characteristics support long-cycle operation under industrial hydrometallurgical conditions.

Specifications

Storage & Handling

Store N263 in a dry, well-ventilated warehouse under normal temperature conditions. Avoid prolonged exposure to high temperature and humidity to maintain product stability. Keep containers tightly sealed to prevent contamination.

During handling and industrial dosing, avoid direct skin and eye contact. Standard chemical protective equipment should be used. Keep away from strong oxidizing substances to ensure long-term storage stability and consistent extraction performance.

Advantages / Limitations

Advantages

N263 provides high selectivity and strong loading capacity for tungsten, molybdenum, vanadium and rhenium extraction. It operates efficiently across a wide pH range without additional protonation requirements, simplifying hydrometallurgical process operation.

Its excellent phase separation performance, low emulsification tendency and stable recycling characteristics make it suitable for continuous industrial extraction circuits while helping reduce reagent consumption and processing costs.

Limitations

N263 is specifically designed for anion-complexed metal extraction systems. It has limited applicability for conventional divalent base metal cations and is not a universal extractant for general mineral processing applications.

Summary

N263 (TCMAC / Trioctylmethylammonium Chloride) is a high-purity quaternary ammonium salt extractant specialized for anion metal separation in strategic mineral hydrometallurgy. With proven industrial applications in tungsten-molybdenum-vanadium separation and rhenium recovery, it provides stable, selective and economical solutions for advanced metal purification and resource recycling.

N263 (TCMAC Quaternary Ammonium Extractant) – FAQ

Q1. What are the optimal acidity conditions for extracting tungsten, molybdenum, and vanadium with N263 in hydrochloric acid systems?

N263 is a quaternary ammonium extractant commonly applied for the recovery and separation of anionic metal complexes in acidic hydrometallurgical systems. The optimal acidity range for tungsten, molybdenum, and vanadium extraction depends on the metal species present, chloride concentration, impurity composition, and organic phase formulation. In practical operations, hydrochloric acid concentration is optimized through solvent extraction testing to determine distribution coefficients and separation factors. Parameters including phase ratio, extraction stages, and stripping conditions should be evaluated together to establish a stable process window for efficient metal recovery.

Q2. How selective is N263 for tungsten, molybdenum, and vanadium extraction from solutions containing arsenic and antimony impurities?

N263 can provide selective extraction of anionic metal complexes from acidic solutions containing tungsten, molybdenum, and vanadium. However, arsenic and antimony species may influence extraction behavior depending on their oxidation states, concentration, and solution chemistry. Selectivity is normally improved through feed purification, acidity adjustment, scrubbing stages, and optimized organic phase composition. Laboratory solvent extraction tests are recommended to evaluate impurity distribution and determine suitable operating parameters. Proper process design helps maximize target metal recovery while minimizing unwanted co-extraction of impurities.

Q3. Can N263 be combined with TBP to improve rhenium extraction from high-iron solutions?

N263 and TBP represent different extractant chemistries and may be evaluated as mixed extraction systems for complex hydrometallurgical solutions containing rhenium and high iron levels. The combination may influence metal loading behavior, selectivity, and phase properties depending on solution acidity, iron concentration, and organic composition. The actual performance should be verified through laboratory and pilot-scale solvent extraction studies. Key evaluation parameters include extraction efficiency, impurity transfer, stripping performance, and organic phase stability during repeated recycling operations.

Q4. Does N263 remain stable when processing high-chloride tungsten and molybdenum solutions?

N263 is suitable for evaluation in chloride-based hydrometallurgical systems where tungsten, molybdenum, or other anionic metal complexes are present. High chloride concentrations may affect phase behavior, interfacial characteristics, and equipment compatibility depending on operating conditions. Long-term performance depends on factors such as acid concentration, temperature, impurity levels, and diluent selection. Industrial application should include monitoring of phase separation, organic losses, and potential crud formation. Pilot testing under actual feed conditions is recommended to confirm extraction stability and operational reliability.

Q5. How does acidity influence tungsten, molybdenum, and vanadium separation factors in continuous counter-current extraction using N263?

Acidity is a critical parameter in N263 extraction systems because it affects the formation of anionic metal complexes and their interaction with the quaternary ammonium extractant. Changes in acid concentration can significantly influence distribution coefficients, extraction selectivity, and impurity behavior. In continuous counter-current circuits, acidity control should be optimized together with organic-to-aqueous ratio, extraction stages, residence time, and stripping conditions. Laboratory simulation and pilot testing are commonly used to establish suitable operating conditions for stable separation of tungsten, molybdenum, and vanadium.

Q6. What stripping conditions are commonly used for recovering tungsten from N263-loaded organic phases?

The stripping process for N263-loaded organic phases depends on the extracted metal species, loading capacity, and downstream recovery requirements. Alkaline stripping systems such as ammonia solution or sodium hydroxide are commonly evaluated for transferring tungsten and related metals back into aqueous phases. The optimal reagent concentration, phase ratio, temperature, and stripping stages should be determined through laboratory testing. Proper stripping design helps achieve high metal recovery while maintaining the extraction performance and recyclability of the N263 organic phase.

Q7. How can organic phase losses and regeneration requirements be managed during long-term N263 solvent extraction operation?

During continuous solvent extraction operation, N263 organic phase performance may be affected by mechanical losses, entrainment, impurities, and prolonged chemical exposure. Regular monitoring of organic concentration, metal loading capacity, phase separation behavior, and extraction efficiency helps identify when regeneration or organic adjustment is required. Regeneration methods depend on the impurity profile and operating conditions, and may include washing or chemical treatment steps. Proper organic management practices can extend reagent service life and improve the consistency of tungsten, molybdenum, and vanadium recovery circuits.

Q8. Is N263 suitable for continuous industrial operation above 55°C?

N263 application at elevated temperatures requires evaluation of thermal stability, phase behavior, and long-term extraction performance. Temperature affects viscosity, mass transfer characteristics, distribution coefficients, and organic phase stability. For operations above 55°C, pilot testing under representative process conditions is recommended to determine suitable temperature limits and evaluate possible organic degradation or increased losses. Maintaining appropriate temperature control, selecting compatible diluents, and optimizing process parameters can support stable continuous solvent extraction operation.

Q9. Can N263 be combined with P350 to improve separation of tungsten, molybdenum, and vanadium?

N263 and P350 have different extraction mechanisms and may be considered as complementary reagents in complex hydrometallurgical separation systems. Combined extractant approaches can potentially modify selectivity, loading characteristics, and impurity rejection depending on solution chemistry and process objectives. The effectiveness of N263/P350 systems depends on factors including metal concentration, acidity, competing ions, organic formulation, and circuit configuration. Laboratory solvent extraction studies are recommended to determine suitable extractant ratios, extraction stages, and stripping conditions for specific tungsten, molybdenum, and vanadium recovery applications.

Q10. What are the key process parameters for producing high-purity rhenium products using N263 extraction technology?

High-purity rhenium recovery using N263 requires careful control of feed preparation, extraction selectivity, impurity removal, stripping efficiency, and downstream purification steps. Important operating parameters include acidity, rhenium concentration, organic-to-aqueous ratio, extraction stage number, temperature, and control of competing anions. N263 serves as a separation reagent within the overall hydrometallurgical process, and final product quality depends on complete circuit optimization. Laboratory evaluation and pilot validation are recommended to establish reliable operating conditions for consistent high-purity rhenium production.