Recovery of Metals such as Vanadium from Asphaltenes.

摘要

1,167,829. Purifying asphaltenes. SHELL INTERNATIONALE RESEARCH MAATSCHAPPIJ N.V. 15 March, 1968 [17 March, 1967], No. 12786/68. Heading C5E. [Also in Division C5] Metals, especially V, are removed from oilfree asphaltenes by treatment with an acid and oxidant or an oxidizing acid. Asphaltenes are crude oil distillation residues which are insoluble in 3-10 C hydrocarbons. Preferably 2-10 M HNO 3 is used as oxidizing acid; other suitable acids are H 2 SO 4 ,H 3 PO 4 , and hydrohalic acids, and suitable oxidants are H 2 O 2 and alkali metal chlorates or bichromates. O 2 may additionally be used to oxidize reduction products, e.g. NO and NO 2 to HNO 3 . Treatment may be effected at 15-100‹ C. for 1 min.-24 hrs. Using HNO 3 , the temperature may initially be 15-50‹ C. to preoxidize the asphaltenes, and the metals are then extracted at 50-100‹ C. Alternatively, the asphaltenes may be preoxidized with air at 150-200‹ C. The HNO 3 solution used may contain V5+ compounds and be saturated at below 50‹ C., treatment being effected at above 50‹ C. A wetting agent may be present during treatment. The metalcontaining acid solution may be recycled, and eventually treated with O 2 or air at above 50‹ C. then cooled to precipitate V5+compounds, mother liquor being recycled.