Abstract: A system, process and method for remediating contaminated soil and solvent recovery. A solvent mixture including a polar and a non-polar solvent is mixed with contaminated soil in mixing vessels, allowing the solvent mixture to extract contaminates from the soil. The solvent mixture is separated from the soil using bicanting units to form a solvent stream and a soil stream. The soil stream goes through air sparging in a dryer to remove residual solvent vapor. Water and/or micro-fines are extracted from the solvent stream using a centrifuge. The solvent stream undergoes distillation in a distillation unit to remove the containments from the solvent stream, while recovering separately the solvent mixture and a product. The recovered solvent mixture can be recycled back to the mixing vessels. The contaminates can be BTEX or F1-F4 hydrocarbons, and the product can be oil or other hydrocarbons. The system can be mobile.

Abstract: A sulfurous compound such as a sulfur-rich “float” (concentrate) obtained by flotation of the residue from the leaching of a zinc concentrate is heated at a temperature not lower than the melting point of sulfur but below its boiling point, preferably not higher than 200° C., more preferably not higher than 140° C., and the evolving gas containing sulfur vapor is cooled at a temperature less than the melting point of sulfur, preferably at ordinary temperature, to condense sulfur.

Abstract: A sulfur purification process is provided. Ash-containing molten sulfur is fed to a centrifuge and subjected to centrifugation under controlled conditions at G forces at least about 4,000 times that of gravity. The centrifugation generates a purified sulfur product and a high-solids sulfur waste stream. A solid bowl disc centrifuge provided with conical discs is used to effect the centrifugal separation of solids from liquids at G forces of at least about 4,000. The centrifuge and related piping system are equipped with heating means so as to maintain the temperature of the sulfur above about 250° F. If large volumes of sulfur are to be treated, e.g., 40 or more long tons per hour, a pretreatment step, where the molten sulfur is first subjected to centrifugation at G forces at least about 4,000 times that of gravity in one or more nozzle bowl centrifuges, is added in order to obtain satisfactory results.