The raw materials of rhenium mainly come from the by-products of molybdenum smelting process. Generally, rhenium content in molybdenum concentrate is between 0.001% and 0.031%. But the rhenium content of molybdenum concentrate from porphyry copper mine can reach 0.16%. In addition, some copper, platinum metal ore, niobium mine, zinc blende smelting dust, slag, waste liquid processing low-grade molybdenum ore and rhenium waste materials such as platinum rhenium catalyst and rhenium waste alloy can also be used as raw materials for rhenium production.
The extraction method of rhenium shall be determined according to rhenium raw materials and rhenium products. When extracting rhenium, rhenium solution is first prepared from raw materials containing rhenium. The solution is separated and purified to extract pure rhenium compounds. Then, rhenium powder is obtained by hydrogen reduction, electrolysis of aqueous solution, and hot dissociation of halide. The process of extraction of rhenium mainly includes the process of raw materials production of rhenium, separation of rhenium molybdenum, preparation of intermediate compounds of rhenium, preparation of crude rhenium powder and refining and densification of rhenium.
Rhenium powder in the first article 6 mpa pressure made billet, billet article under 1200 ℃ sintering in vacuum or ammonia, then article presintering in vertical furnace in 2700-2850 ℃ under the high temperature sintering, finally get the theoretical density of more than 90% of rhenium. This method USES sintering bar as raw material to purify crude rhenium by arc smelting, electron beam smelting and zone smelting. The rhenium ingots obtained by electron beam melting are columnar crystal with purity of 99.99%. The product obtained by regional smelting is a single crystal of rhenium with spectral purity.
At present, rhenium extraction metallurgy has formed three major links of production of rhenium compounds, rhenium powder and rhenium materials. The future development of the rhenium smelting industry is to expand the source of raw materials of rhenium, improve the recovery rate of rhenium in the process of smelting such as molybdenum and copper, develop and perfect flash roaster and circulating fluidized roasting method, and develop new technologies for more effective rhenium recovery, especially solvent extraction and ion exchange.
