| abstract |
Used drilling muds containing substantial quantities of organic liquids and water-soluble salts are treated to render them environmentally acceptable for disposal purposes, by drying the muds to evaporate all liquids, aqueous and non-aqueous, preferably in a shell-and-tube type heat exchanger through which they are conveyed and held in suspension by screw conveyors, and preferably with the vapors thus generated flowing in a direction counter-current to the mud. Water-soluble salts are removed from the dried mud components by dissolving with water, and the vapors are condensed and phase separated for further purification and re-use if desired. |