Liquid salt could be the answer to bituminous sand tailings ponds

Researchers at the University of Calgary aim to eliminate aqueous tailings from bitumen extraction. Wastewater from oil sands mining operations has long been a challenge for Canada’s energy industry, much of which ended up in industrial tailings ponds. But the scientists and engineers at the University of Calgary aim to eliminate aqueous tailings from the oil sands production process with the help of specialized liquid salt. The new pilot project aims to detoxify the oil sands and wastewater for a safe return to the Athabasca River.

Hot water is used in mining operations of oil sands to extract oily bitumen from the sand, and the resulting wastewater ends up in tailings ponds to settle and then reuse. Alberta has an estimated 1.3 trillion liters of fluid tailings in tailings ponds. Paula Berton and Steven Bryant believe that ionic liquids, or liquid salt, offer a possible solution. By using ionic liquids instead of water in the extraction process, researchers say they can eliminate the production of aqueous tailings, while ionic liquids can be recycled. They anticipate that surplus sand can be returned to the ground. Ionic liquids and the resulting sand are not toxic, they say. “We have found a way, using advanced materials, to make bitumen extraction from oil sands efficiently, using much less energy and without using water at all, and thus eliminating the problem of tailings,” said Bryant, a part of the University Schulich. Ingeniery school.

Out of the lab

They believe that the ionic liquid process could also be used by on-site projects. The team, which received funding from the Canada Chairs Program for research excellence, has obtained a patent and was recently published by the American Chemical Society. Scientists have been investigating ionic liquids (salts with organic cations that melt at low temperatures) for decades, but they have become an important subject of study for modern chemistry. Because they can dissolve many things and have low volatility, some of them have been called “green” solvents and have been used in chemical processes that include separation and purification. “Another property of these materials in general, I would say, is that they are really stable,” Berton said.

Recycled liquids

The researchers say that ionic liquids will also work at room temperature, which means that less energy is needed in the process and, therefore, less carbon emissions. Because ionic liquids are recycled immediately, Bryant explained, the volumes required are much smaller than the volumes of water used in current processes. “There are many reasons why these are not your grandfather’s solvents,” Bryant said. Nina Lothian, director of the fossil fuel program at the Pembina Institute, a group of green energy experts said that the extraction of oil sands without tailings is a concept that the industry has been exploring for a long time. “I think it has a lot of potential,” Lothian said. “I would applaud the efforts to discover the technology that would extract oil sands without producing tailings, but that doesn’t eliminate the [existing] tailings we have in the landscape today.”

Tailings are a priority

Alberta’s oil sands tailings ponds have been criticized by environmentalists for years, gaining international attention in 2008 following the death of 1,600 ducks. Water in tailings ponds contains contaminants ranging from salts and heavy metals to polycyclic aromatic hydrocarbons and naphthenic acids. The Alliance for the Innovation of the Oil Sands of Canada (COSIA), which coordinates the research of 13 oil sands companies, has identified the tailings as one of its key environmental priority areas. A COSIA spokesman said they are aware of the work of the U U researchers. “The use of ionic liquids … is one of the numerous treatment technologies that are being researched and developed to improve tailings management,” Rob Gray said in a statement. “This work is in the early stages and is currently not a COSIA project, but ionic liquids can become a tailings treatment of interest to COSIA in the near future.”

SOURCE: Tony Seskus · CBC News