Study on Electrochemical Dissolution and Precipitation Separation of W-Re Alloy

In view of the waste of W-Re alloy, the electrochemical dissolution method was used to dissolve W, Mo and Re completely in the sodium hydroxide solution, and then the selective precipitation separation of the electrolytic solution performed using calcium chloride to precipitate W-Mo and potassium chloride to precipitate Re. The suitable technological parameters for electrochemical dissolution and precipitation separation of W-Re alloy waste were studied and determined. The results show that when the cell voltage is 2.5 V, the NaOH concentration is 100 g.L-1, the electrolysis temperature is 30-40 degrees C, the electrode distance is 20 similar to 30 mm, and the total W-Re ion concentration is 30 similar to 35 g.L-1, the dissolution ratios of W, Mo and Re are all more than 99%, the current efficiency is over 99%, and the electrolysis energy consumption of W-Mo-Re waste wire and W-Re scrap is 1.43 and 2.28 kW.h.kg(-1), respectively. The wire waste is easier to be electrochemically dissolved than the block waste. Under the conditions of reaction temperature of 80 degrees C, CaCl2 dosage of 3 times of theoretical dosage, OH - concentration at 9.5 g.L-1, W ion concentration at 23.18 g.L-1, reaction time for 2 h, the precipitation ratios of W and Mo are 99.86% and 99.55%, respectively. The white precipitate of CaWO4/CaMoO4 mixture is obtained, and its SEM morphology shows it is mainly spherical particles. After the above two processes, the recovery ratios of W and Mo are 98.86% and 98.55%, respectively and KReO4 white crystals are prepared.