Spent shale

It consists of inorganic compounds (minerals) and remaining organic matter known as char—a carbonaceous residue formed from kerogen.

Depending on the extraction process and the amount of remaining organic matter, spent shale may be classified as oil shale coke, semi-coke or coke-ash residue, known also as oil shale ash.

[2] Oil shale coke is created by chamber ovens which were used for oil shale gas production.

[3] Spent shale can be used as ingredients in cement or brick manufacture.

[1][4][5] In Jordan, usage of spent shale for the production of sodium carbonate, ammonium sulfate, and potassium sulfate has been studied.

A photograph of dark gray/silver piles of spent shale lumps.
Mounds of spent shale