Waste liquid rhenium recovery technology

Rhenium disulfide was oxidized by furnace gas and flew in the form of Re2O7 (boiling point Re2O7 363℃) during the roasting of molybdenum concentrate. The dust removal system produces dust rich in rhenium. According to V.I. Bibikova, up to 90 percent of rhenium can be trapped by electrostatic precipitators.
However, it should be kept in mind that Re2O7 will only be captured if adequate cooling of the furnace gas for the ELECTROSTATIC precipitator is ensured. The rhenium content in dust is 0.01 ~ 0.2%. It is not difficult to remove rhenium from the dust.
The dust is filtered with water. In this case, Re2O7 enters the solution in the form of rhenic acid. To increase the concentration of rhenium, the solution evaporates. And then you add potassium chloride to the solution. This deposits potassium perrhenate as a white precipitate. For purification, perrhenate is recrystallized.

To extract rhenium and other valuable components, the broken furnace deposits are treated with dilute sulfuric acid. Rhenium is left in an insoluble residue with copper, molybdenum, nickel, and many other metals. Fine sludge is naturally oxidized in the air for several months after being washed. During oxidation, water-insoluble oxides, phosphates, molybdate, and basic sulfates of some metals are formed. In this case, rhenium forms a water-soluble perrhenate of the divalent metal, which enters the solution when the oxidized sludge is leached. The solution is concentrated by evaporation and potassium perrhenate is separated from it.



 

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