Separating Bituminous Sands

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Clark continued with his research, and in the early 1930s he discovered what the role of the reagent was in separation. At this time, Clark was working with sand coming from a quarry to the north of the previous quarries with which he had worked. He noticed the sands from this location were not separating the way he expected them to.

It turned out the sands from this quarry were different from those mined from others in that there was a considerable amount of soluble salts present in them. This caused a high level of acidity, which was causing the difficulty in separation. To separate them, the sands had to be neutralized by an alkaline substance, such as soap reagent.

Clark further discovered that certain neutralizing agents worked better than others. While lime and caustic soda did not work well, soda ash worked perfectly. In his 1931 report to the Alberta Research Council, Clark states, “generally speaking, if bituminous sand as found in Northern Alberta is mixed and heated with a solution of soda ash till all its acidity is neutralized and then washed in hot water, practically one hundred percent of the bitumen content of the same will be recovered.”

Clark continued his research, and was granted one more patent in 1948. The patented process improved upon previous separation techniques by identifying the role of air bubbles in separation. Air bubbles occur naturally in the oilsands and are necessary for the separation of the bitumen. Bitumen particles attach to the air bubbles and float to the surface.

If there is too much air, however, sand will start attaching to the oil bubbles, causing excessive sand to be present with the bitumen. The patent makes it clear that the amount of air used must be controlled in order for the process to work efficiently. Though Clark discovered this principle over fifty years ago, it is still employed today.

Washing Out the Sand The problem of separating bitumen from the oil sands was one approached by several innovative minds, from G. Christian Hoffman to Dr. Karl Adolf Clark. In this excerpt from the JuneWarren publication, The Great Canadian Oil Patch: The Petroleum Era from Birth to Peak, author Earle Gray describes some of the scientific efforts made to solve the mystery of separating bituminous sands. Read more…