2001 Volume 42 Issue 11 Pages 2465-2471
The fly ash generated from oil burning is collected with a dust collector installed on a boiler. Recently, The necessity of developing a new process for recycling fly ash has recently received considerable attention due to the rather short life of landfills used for the disposal of a fly ash. Many tests have therefore recently been carried in order to develop a recycling process for useful components such as V and Ni following the concept of zero emission. The results can be summarized as follows: (1) V ions in the fly ash can be leached out by mixing with an equal quantity of water and most of the components that remain in the residue can then be leached out by adding an aqueous ammonia solution. Using this two-stage leaching method, all components of interest can be leached out without heating or using significant amounts of chemicals. (2) It was possible to recover of Ni and V ions by a solvent extraction method which resulted in a high purity of the recovered compounds. (3) The sulfate ions, Mg ions, and ammonium ions that remained in the solution after the solvent extraction process to recover Ni and V ions were recoverable through a crystallization and distillation process as calcium sulfate, magnesium hydroxide, and aqueous ammonia solution, respectively. (4) Based on results of this work, a new recycling system which does not produce secondary waste was developed for fly ash generated from oil burning.