Shale Oil

Mankind was using oil shale because of its combustible property, which does not require complicated processing. Its utilization began in ancient times, when it was employed for decoration and construction purposes. Shale oil was used in medical and military sectors as well. The oil shale was exploited by different countries until the 17th century. One of the interesting oil shales is the Swedish alum shale of Cambrian and Ordovician age because of its alum content and high concentrations of metals including uranium and vanadium. As early as 1637, the alum shales were roasted over wood fires to extract potassium aluminum sulfate, a salt used for tanning leather and also for fixing colors in fabrics. Late in the 1800s, the alum shales were retorted on a small scale for hydrocarbons. Production continued through World War II but ceased in 1966 because of the availability of cheaper supplies of petroleum crude oils. A part of uranium and vanadium was also extracted from alum shales. By the mid 19th century, the modern application of oil shale was initiated and started growing before World War I because of bulk production of automobiles. Due to the massive demand of this type of transportation, the consumption of the gasoline was increased and the supply was decreased. Hence, during World War I, the oil shale projects were developed in various countries. Because of the easy, convenient, and economic accessibility of conventional crude oils, the decline in production of the oil shale formations was observed after World War II. As of 2010, oil shale was commercially employed in Estonia, China, and Brazil, while several countries are thinking about starting and restarting commercial use of oil shale.