MECS® Metallurgical Sulfuric Acid Process Technology

Metallurgical Sulfuric Acid
Process Technology


DuPont Clean Technologies provides premier MECS® technology , engineering and equipment  for metallurgical off-gas sulfuric acid plants. Whether your drivers are stricter pollution control or deteriorating grades of ore, our off-gas metallurgical process generates quality sulfuric acid, using technologies that set the standard for performance, reliability, energy recovery, and emissions reduction. 

 Our expert engineers benefit from over two centuries of combined experience acquired by building over 1000 acid plants worldwide. They have the in-depth knowledge required to assess your complete process chain from the upstream metallurgical process right through to acid production. Our specialists can then design a cutting-edge metallurgical acid plant to recover and regenerate quality sulfuric acid for your organization, while meeting stringent emissions requirements and sustainably increasing your efficiency and cost-effectiveness. Our processes and plant designs feature breakthrough MECS® technologies, many of which have revolutionized performance, cost controls, and quality for the sulfuric acid industry. 



DuPont Clean Technologies developed its pre-conversion technology to more effectively manage high-SOconcentration off-gas from smelting operations.  Our unique configuration (see figure below) reduces CAPEX while maximizing energy recovery by converting a portion of the high strength gas to SOahead of the main converter.  Pre-converted gas is then mixed with SO3-bearing gas and sent to pass 1, where equilibrium conditions prevent excessive first pass outlet temperatures.  By processing a high concentration of SO2, the plant is able to produce a maximum amount of steam, in particular when combined with MECS®’s HRS™ technology.  MECS®’ pre-conversion configuration that treats high concentrations of SO2 also significantly reduces power consumption, adding to the profitability of the plant.  With 7 references and counting, MECS®’ pre-conversion design is the technology of choice to treat high concentration off-gas from modern smelters.  

 We also offer conventional technology to treat gas from other metallurgical operations.

MECS® Metallurgical
Process Description


The MECS® Metallurgical process is based on years of experience in ore and metal process design. We provide metallurgical plants around the world with technologies that can treat off-gas with high levels of impurity including arsenic, fluorides and mercury. 

Off-gas from essentially any continuous or semi-continuous metallurgical process that contains SO2 gas is pulled through the primary MECS® DynaWave® Reverse Jet Scrubber, where it is cleaned and cooled to its adiabatic saturation temperature by recirculation of weak acid. Next, the gas is cooled in the high-efficiency MECS® ZeCor® Tower, to a point where the moisture level is reduced to the amount required in the product acid. Depending on the level of impurities in the feed gas, another DynaWave® Jet Scrubber may be used. The final stage of gas cleaning is a MECS® WESP, which removes both liquid and solid particulate matter, to prevent corrosion and fouling in the acid plant. The gas is then pulled through the high-efficiency ZeCor® Drying Tower, where remaining water vapor is removed. A MECS® Brink® Mist Eliminator provides efficient acid mist removal for the protection of the main compressor. The dry, clean gas is then compressed and introduced to the converter system. 
In the contact section of the plant, the gas flows through three passes of MECS® GEAR™ and Cesium Catalyst, as well as their respective cooling equipment, and is then absorbed with 98% sulfuric acid (H2SO4) in the Interpass Absorbing Tower. The lean SO2 gas flows through another Brink® Mist Eliminator to remove fine mist particles, protecting downstream equipment. The clean gas is then reheated and enters the converter to complete the fourth conversion pass of SO2 to SO3 using MECS® Super Cesium Catalyst SCX-2000, to achieve the highest possible conversion. The resulting SO3 is absorbed in 98% H2SO4 in the ZeCor® Final Absorbing Tower. Brink® Mist Eliminators are installed in the final tower to ensure the stack gas will meet acid mist environmental regulations. 

By using this combination of metallurgical process technologies, non-ferrous metal producers will not only be able to reduce emission levels as required, but also cut energy and water use while optimizing equipment utilization. Among the adopters of the MECS® Metallurgical Sulfuric Acid Process Technology is the world’s largest copper producer, Codelco

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