Extraction and separation of tungsten from acidic high-phosphorus solution

The utilization of high-phosphorus tungsten ores has attracted extensive attention with the mining and utilization of rich tungsten ores. To extract and separate tungsten from acidic high-phosphorus solution effectively, a novel process was developed. Firstly, tungsten was extracted directly in acid medium by solvent extraction . 99.8% tungsten in acidic high-phosphorus solution was extracted with Aliquat 336 in kerosene by one extraction stage under the conditions of O:A   =   1, pH   =   2, 25   °C, t   =   10   min, 5% v/v 2-Octanol and 10% v/v Aliquat 336. And then, tungsten and phosphorus were preliminary separated through stripping process. Over 95% tungsten were recovered after five stripping stages under the optimum stripping conditions of 2.5   M ammonium bicarbonate , 8   min stripping time, O:A   =   1:1, pH   =   9, and 60   °C, but only about 1.2% phosphorus was recovered from feed liquor. Finally, a small amount of phosphorus left in strip liquor was deeply removed by magnesium salt precipitation method on the optimum conditions of pH   =   10.0, 25   °C, reaction time 1   h and Mg/P molar ratio of 1:2 and the ammonium tungstate solution meeting the requirements of producing high-quality ATP can be obtained successfully. Compared to traditional phosphorus removal route, the process in this paper can help extract tungsten directly in acidic medium and decrease the quantity of phosphorus through extraction-stripping process, significantly reducing the consumption of alkali and magnesium salt and improving the separation efficiency of tungsten from acidic high-phosphorus solution.