China Nonferrous Metallurgy

Industrial primary ammonium rhenate is often accompanied by a variety of impurities. The traditional purification methods has the problems of low efficiency， high cost and strict equipment requirements. In this study， a crude ammonium rhenate product was used as the raw material， and its main impurities were copper， sulfur， selenium， iron， arsenic， etc. The high-purity ammonium rhenate was prepared by the multi-technology synergistic process of ‘pure water dissolution + ultrasonic assisted crystallization + hydrogen peroxide oxidation impurity removal + electrodialysis depth impurity removal’， and the process parameter optimization test and verification test were carried out. In the process of pure water dissolution， most of the copper sulfide and copper selenide impurities that are not easily soluble in water can be removed by filtration under the condition of stirring and dissolving at 85℃ for 1 h，because of ammonium rhenate easily dissolved in water at high temperature. Ultrasonic assisted crystallization process can improve the formation rate of crystal nucleus by the cavitation effect of ultrasonic wave， and it is difficult for impurity elements to adhere to the surface of the nucleus by its highfrequency vibration， and this process removes most of the arsenic and iron in the solution. Hydrogen peroxide oxidation impurity removal process can oxidize S^2- ， Se^2- ， Cu⁺ and other low valence impurity ions， so that it can produce high valence insoluble matter， and then filter to remove. The electrodialysis deep impurity removal process uses the ion exchange performance of the activated membrane to remove the potassium， sodium and other elements that are difficult to remove in the solution， as well as the residual copper and iron ions. In this process， crude ammonium rhenate with a grade of about 30% was used as raw material， and 5 N high-purity ammonium rhenate was successfully prepared which meeting the requirements of standard YS/T 894—2018. The process abandons the use of complex chemical agents， and the synergistic effect is significant， which greatly improves the impurity removal efficiency； and the process can stably and efficiently prepare high-purity ammonium rhenate products， which provide a new idea for the preparation of high-purity ammonium rhenate.