Preparation of phosphor-tungstic acids (H3PW12O40) by solvent extraction with 2-octanol

• Published in: Hydrometallurgy 2019-05, Vol.185, p.291-296
• Main Authors: Li, Yongli, Zhao, Zhongwei
• Format: Article
• Language: English
• Subjects: 2-Octanol; H3PW12O40; Solvent extraction; Tungsten; Water stripping
• ISSN: 0304-386X; 1879-1158
• DOI: 10.1016/j.hydromet.2019.03.005

For more than a hundred years, extraction with ethyl ether has been the most used method for synthetizing H3PW12O40. However, the use of ethyl ether as the extraction agent faced many problems, such as strict regulation by public safety and environment authorities, poor operating environment, significant dissolution loss, low yields (approximately 80%), and difficulty in realizing continuous production. To overcome these problems, a new extraction method has been proposed in this paper, which uses 2-octanol as the extraction agent and water as the stripping agent. Under optimal conditions (30% 2-octanol in kerosene, O:A = 1:1, 180 g/L H2SO4, 20 g/L H3PO4, 45 °C, and a contact time of 2 min), 90.2% of H3PW12O40 contained in the solution was extracted in a single stage; the loaded H3PW12O40 could then be stripped completely via 3-stage continuous countercurrent stripping by maintaining O:A = 5:1, 65 °C, and t = 5 min. Finally, the obtained strip liquor, containing more than 550 g/L H3PW12O40, was evaporated to obtain crystals, resulting in an increased recovery rate of 10%. [Display omitted] •A low cost method for synthesizing H3PW12O40 was proposed to replace the method with ethyl ether.•The new method uses 2-Octanol as the extraction agent, water as the stripping agent.•Compared with the traditional method, the recovery rate of the new method is increased by 10%.