Rhenium production raw material mainly comes from the by-product of molybdenum smelting process. The content of rhenium in general molybdenite concentrate is between 0.001% and 0.031%. However, the rhenium content of molybdenum concentrate from porphyry copper ore can reach 0.16%. In addition, some copper, platinum group metals, niobium, sphalerite smelting smoke, slag and treatment of low-grade molybdenum ores and rhenium-bearing wastes such as platinum-rhenium catalyst and rhenium-bearing waste alloys can also be used as raw materials for rhenium production.
The extraction method of rhenium needs to be determined according to the raw materials and products containing rhenium. When extracting rhenium, the solution containing rhenium was first prepared from the raw material containing rhenium, the solution was separated and purified to extract pure rhenium compounds, and then the rhenium powder was obtained by hydrogen reduction method, aqueous solution electrolysis method and halide thermal dissociation method, and then the material was processed by powder metallurgy method. The process of rhenium extraction and metallurgy mainly includes the production of raw materials containing rhenium, the separation of molybdenum from rhenium, the production of intermediate rhenium compounds, the production of crude rhenium powder and the refining and densification of Rhenium.
The rhenium powder was first made into the green strips under the pressure of 6MPa, the green strips were sintered under 1200℃ in vacuum or ammonia gas, and then the pre-sintered strips were sintered under high temperature at 2700 -- 2850℃ in the vertical furnace. Finally, the rhenium strips with theoretical density over 90% were obtained.
The raw rhenium was purified and purified by arc smelting, electron beam smelting and regional smelting. The rhenium ingot obtained by electron beam smelting is columnar crystal with purity of 99.99%. The product obtained by regional smelting is the single crystal of rhenium with spectral purity.
Now, the pattern of producing rhenium compound, rhenium powder and rhenium material has been formed in rhenium extraction metallurgy. The task of the future development of the rhenium smelting industry is to enlarge the source of rhenium raw material, improve the recovery rate of Rhenium in the smelting process of molybdenum and copper, develop and perfect the flash roaster and circulating fluidized roasting method, and at the same time develop more effective new processes of Rhenium recovery, especially solvent extraction and ion exchange method.
