Mercury retorting is a process that is used to treat materials containing a significant concentration of mercury prior to smelting or further purification to minimize the release of mercury vapors. In a mercury retort, mercury is distilled from mercury rich sludge or precipitate, typically containing mercury, gold, silver, and impurities. The wet sludge is slowly heated to the boiling point of mercury; the mercury vapors produced are then condensed and collected in a condensation pot, from which it is transferred a containment vessel. Removal of mercury by retorting is an important process because the mercury vapors that can be released during smelting can result in serious health issues for workers.

KCA fabricates mercury retorts that can process up to 40 cu. ft of wet or dry solids per batch. Temperature and time are fully automated. Below is a labeled photograph of one our fully constructed retorts, KCA’s Model R17E,

KCA’s Mercury Retort typically consists of the following elements:

  • Stainless steel chamber where trays of precipitate are heated to expel mercury

  • Heating chamber lined with refractory wool insulation

  • Main control panel containing the Smart Controller (SCR), Eurotherm main process and high limit controllers

  • Skid mounted electrical transformer, vacuum pump complete with starter, retort safety switch and furnace safety switch

  • Mercury receiver for safe collection of the condensed mercury vapors

  • Shell and tube heat exchanger for additional cooling of the mercury vapors

  • Large carbon filter stainless steel tank filled with sulfur impregnated carbon

  • Vacuum pump which maintains negative pressure throughout the entire system

  • Pan handler cart for the loading and unloading of pans into the tray chamber

  • Air-water separator for the vacuum pump discharge

  • Vacuum pump air exhaust chimney

KCA also offers engineering, design and installation supervision services to ensure the mercury retort area has adequate containment features suitable for the installation of the unit.