Acid-digestion and Washing

There are three main reasons for digesting soils in hot acid - to determine the organic carbon content, to extract mineral elements for their total content, and to determine total nitrogen by the Kjeldahl digestion. 

The first is called Tinsley s wet combustion (Tinsley, 1950), and uses a highly corrosive mixture of sodium dichromate, and concentrated perchloric and sulphuric acids. For undergraduate practical classes, the safer loss on ignition method might be considered more appropriate. 

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Other treatment processes like acid digestion and washing processes, developed primarily for the recovery of plutonium at a time when plutonium was considered as a rare and valuable material, are presently of reduced interest. Now volume reduction and production of a stable waste form for disposal are the main objectives for conditioning. 

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