Recovery of Precious Metal Values from Oil Sands Tailings Slurry

Background

The oil sands industry in Northern Alberta currently generates more than 11,000 tonnes of tailings slurry per day, 365 days per year, as waste from the process of bitumen extraction. These tailings are deposited in containment ponds to limit residual oil from leaching into water systems. It has been found that the tailings are a unique and rich source of titanium (5-10 % on solids), zirconium (2-5 %) and iron and rare earth minerals (8-12 %). These valuable minerals are at present not being recovered. The global titanium market is significant – approximately $10 billion per year in annual sales. The market is spit as follows: 60% paints and coatings, 20% plastics, 13% pulp and paper and 7% for other uses.

Description of the Invention

Researchers at Western have developed a superior and efficient process to concentrate and extract the valuable minerals from the tailings immediately following the hot water bitumen extraction and centrifugal processing steps used for oil recovery.

This process, which has been proven at pilot scale, would be added to the extraction stream after the removal of bitumen and just before tailings are moved to containment. At this stage of the process residual energy and a frothing agent would be used to produce a froth floating on the tailings slurry, which contains most of the mineral values. After removal of the froth the recovered material including minerals are subjected to incineration or other steps which remove residual bitumen, followed by magnetic separation and mechanical screening to separate the various metal types.

Advantages

The present invention offers a number of competitive advantages, including:

1. Significant cost advantages over previous methods
2. A feasibility study which has been completed, projecting an excellent recovery rate for the production of titanium concentrate, zircon and rare earth minerals.
3. The Western process addresses several environmental concerns.
4. The process exploits a potentially valuable source of minerals that are currently being placed into tailings ponds where recovery will be much more difficult and may not be economically viable.

The technology can be applied to the tailings deposits which already exist and to slurries which will be produced in the future. It produces mineral concentrates which will interest end-users in the paint and coating, pulp and paper, and/or plastics industries, or intermediate industries seeking to supply end-users.

Potential applications include:

• recovery of heavy metals
• pigments applications
• pulp and paper industry
• plastics applications

Canadian Patent 1,326,571 Issued

The University of Western Ontario is interested in seeing this technology applied to major tailings deposits existing and still in production.

UWO would like to license the process either to end-users or to an intermediate seeking to refine the process for subsequent license to an end-user.