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Abstract: Selectively extracting tungsten to purify sodium molybdate solution was studied using primary amine N1923, including various conditions, such as equilibrium pH values, concentrations of extractant in organic phase and metals in feed solution, contact time of extraction and stripping, types of acidic solutions added, temperature of extraction and the dosage of stripping agent. Graphical method using McCabe-Thiele diagram and counter-current extraction simulation (CCES) were used to determine the required stages of deep removal of tungsten. The results show that appropriate concentrations of tungsten and molybdenum in feed solution have great influence on the difficult degree of the separation between the two metals. Organic phase including 0.051M of N1923 modified by LK-N21X diluted in kerosene can extract 92.7% of tungsten in sulfuric acid solution at equilibrium pH value of 7.07 for 10min in one-stage extraction at 15.5°C, and the separation factor reaches 329 under those optimum conditions. A two-stage CCES removes 99.83% of tungsten and obtains the purified sodium molybdate solution where W/Mo (mass ratio) reaches 2.9×10−5. Stripping can be accomplished by NaOH solution completely and quickly. Furthermore, the extraction and stripping reactions of tungsten and molybdenum in equilibrium were proposed. [Copyright &y& Elsevier]

Coking wastewater is generated during high-temperature coal carbonization, coal gas purification and chemical products refining. There is a large amount of coke powder in coking wastewater. Various problems have been brought by coke powder. In this study, a novel method was proposed to remove coke powder from coking wastewater. The removal of coke powder was linked with extraction technology. A series of physical and chemical properties of coke powder were characterized by investigating XRF, XPS, elemental analysis and contact angle. Based on “Like Dissolve Like” principle, different extractants were selected to test contact angle of coke powder. Coke powder extraction experiments with the analysis results were carried out. This study provides a new insight to remove coke powder from coking wastewater. [ABSTRACT FROM AUTHOR]