Recovery of Metals from Petroleum Waste Byproducts

The gasification of carbon feedstocks is used to generate syngas to produce electric power or to synthesize chemicals. Unfortunately, this process also generates waste materials that have few applications, with the majority being landfilled. Petcoke, a byproduct of petroleum processing, is utilized as a carbon feedstock in gasification, generating an ash byproduct high in nickel (Ni) and vanadium (V). Elemental Ni and V are listed in the U.S DOE 2011 Critical Materials Strategy, and are used in advanced technology products such as metal hydride batteries, redox batteries, and specialty alloys. Currently, the U.S. relies on foreign sources of these materials to meet most domestic manufacturing needs.    

The high Ni and V content in petcoke ash byproduct represents a potential source of these elements if an economically viable recovery process can be developed. Current methods for the extraction of Ni and V from petroleum waste byproducts use conventional separation techniques, such as chemical leaching. However, because Ni and V from petcoke gasifier ash are also dissolved in the vitrified slag (or glass), leaching methods for their recovery would require a multi-stage approach that is time consuming and expensive. The complex leaching processes also require the use of large quantities of strong acids, making them environmentally unsuitable.

This invention describes a single-stage process for the extraction of Ni and V from petroleum waste byproducts. The novel process represents a simplified and more environmentally friendly approach for the high yield and high purity extraction of Ni and V. Using this process, Ni and V are both ‘lifted’ above the waste matrix surface, making subsequent separation easier using simple beneficiation processes such as magnetic and gravity techniques; minimizing or eliminating the need for leaching, crushing, and grinding stages.