METHOD OF PROCESSING MOLYBDENITE CONCENTRATES AND MIDDLINGS Russian patent published in 2002 - IPC

FIELD: metallurgy industry, particularly, processing of molybdenite concentrates and middlings. SUBSTANCE: method includes oxidizing roasting at temperature of 550-600 C carried out in two stages: the first stage is performed with oxygen deficiency up to 85-95% desulfurization degree of cinder; the second stage is carried out up to full oxidation of sulfur and formation of metal oxides with oxygen value exceeding stoichiometric value by a factor of 1.5-2.0. Simultaneously volatile oxides of rare metals are driven off and absorbed. Method allows to increase recovery of rhenium and other rare metals into gas phase up to 93-95%; to increase withdrawal of rhenium and other rare metals up to 2.4-3.3 g/l into absorption solutions; to reduce sulfur content in cinder down to 0.5%. EFFECT: simplification in realization, higher e ecological efficiency of progress due to reduced concentration of sulfuric acid in solutions. 1 tbl, 1 ex