Metal Recovery System from Soots Produced by the Gasification Process for Heavy Oil Residue

摘要

Noncatalytic partially combustive gasification to carbon monoxide is one of an attractive process for the utilization of a heavy petroleum residue. The gasification operates in a reducing atmosphere, so a carbonaceous deposit (soot) containing iron, vanadium and nickel is produced. The extractive recovery of vanadium and nickel by nitric acid, sulfuric acid and a mixture of sulfuric acid/ammonium sulfate aqueous solution from the soot obtained from a commercial process was carried out to elucidate the effects of extraction conditions on the recovery rate of metals.Although 80% of vanadium was recovered from the soot collected from the gasification plant without pretreatment, the extraction ratio of nickel was below 20%. The dissolution rate of nickel sulfide, which is the main component in soots, is slower than that of nickel oxide. To improve the recovery rate of nickel, the soot was partially oxidized in air. The extraction ratio of nickel from the 90% oxidized soot rose to about 80%.A basic flow sheet for the metal recovery was propsoed for a commercial plant based on the extraction results obtained.