"This is a summary report for the project entitled ""Nature of Bonding Between Organic Materials and Mineral Constituents of Oil Shale"" (PPBS 20-03-12), authorization number 9111311. Work on this project was begun in FY 1967 and completed in FY 1969. Two manuscripts resulted from this research, ""Use of Carbonic Acid to Concentrate Kerogen in Oil Shale"" by Rex D. Thomas published in the January 1969 issue of FUEL, and ""Concentrating the Kerogen in Oil Shale by Centrifuging"" by Rex D. Thomas and Philip B. Lorenz to be published as an RI. The important results of this research are described in the next paragraphs. The major problem encountered in this research on oil shale was the separation of organic and inorganic material. A new method of concentration of the organic material using carbonic acid was developed. This acid was selected because it dissolves the major mineral constituents (carbonates) yet should not attack the organic material. The best separation is obtained with a carbon dioxide pressure of 200 psi and oil scale particles smaller than 150 mesh. All of the calcium and magnesium in the oil shale , along with some iron and aluminum, is removed and the organic carbon content of the shale is not affected by this treatment. Physical separation by centrifuging can be improved by a factor of 10 by pretreatment with carbonic acid. The separation is further improved by pretreatment with sodium hydroxide (pH 11.5) to remove the clay-like minerals. Subsequent treatment and centrifuging with organic solvents also improved the separation. Analysis of the materials obtained shows that the concentration of organic sulfur and nitrogen compounds is not affected by centrifuging. Organic oxygen compounds, however, are concentrated in the light fraction. Iron compounds other than pyrite appear to be closely associated with the organic material."