Separating Bituminous Sands

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Dr. Karl Clark is strongly associated with the hot water separation of bituminous sands, and while he did not invent the procedure, he improved upon it by utilizing chemical reagents and fine-tuning the process, resulting in the cleanest bitumen achieved at that time.

In 1920, Clark considered the heavy, viscous oil coming from the tar sands as a potential ingredient in road surfacing. At the time, the dirt roads of the prairies were vulnerable to moisture, and Clark thought a bituminous emulsion would be useful for fixing the roads so they could stand up to wet weather.

In the 1920s, standard techniques of emulsifying paving material made use of a soap reagent. Clark found, however, that when he tried this process with the Northern Alberta sands, the sand and the oil (bitumen) separated; the sand sank to the bottom, with the bitumen settling  above it. Unfortunately, bitumen is heavier than water, and so the water involved in the procedure came out on top. As such, it was impossible to recover the bitumen without mixing it with sand again.

Clark explained his discovery in a letter to Dr. H. M. Tory, President of the University of Alberta. Within weeks, Clark was hired to Tory’s Research Department, the precursor to the Alberta Research Council (ARC), in order to study the separation process further. Bituminous sand as a paving material was soon abandoned as it was uneconomical, and so Clark's focus shifted to cleaning the bitumen in order to process it.

Clark began experiments with hot water, an idea pioneered by others such as Sidney Ells, an engineer for the Federal Department of Mines. Tar sands frothed when dispersed in hot water. After months of tests, Clark found that if he created a pulp of tar sand in hot water, a froth of oil would form once more hot water was introduced. This froth then floated to the surface while the sand sank to the bottom, thus allowing the froth to be easily collected from the surface.

With some minor adjustments, this method of separating bituminous sands was patented in 1929, though it would be decades of experimenting with new techniques in oil refinement before the oil sands yielded more valuable petroleum products.