| 摘要 |
PURPOSE:To recover valuable metals in good efficiency by improving the separation of components in ash, by providing a specific means for allowing water, an acid or alkali to act on ash discharged from the dust collector provided in the exhaust gas flue of a heavy oil burning boiler. CONSTITUTION:Water J is added to heavy oil ash A in a mixing tank 1 and both of them are stirred by a stirrer to form a slurry which is, in turn, guided to a dissolving tank 2 where sulfuric acid E is added to the slurry to adjust the pH thereof to 3 or less. Subsequently, the slurry is guided to a separator 3 to perform solid-liquid separation by a filter and the filtrate is introduced into a pH adjusting tank 4. On the other hand, separated carbon sludge is guided to a dissolving tank 13 where recirculated water J is added to said sludge to dissolve residual ammonium sulfate or heavy metals and, thereafter, solid-liquid separation is performed by a centrifugal separator 14 to obtain carbon sludge. The filtrate of the separator 3 is guided to the pH adjusting tank 4 while aqueous ammonia is added to said tank 4 from an aqueous ammonia tank 15 to adjust the pH thereof to 7-8 and vanadium is separated as VO(OH)2. |
