EST offers technological solutions for the reduction in resource consumption and waste minimization (with the resulting reduction in external waste disposal costs) in the chemical pretreatment of metals. EST and its partner companies supply the customer with fully implemented or standalone modules for process tank maintenance such as oil separators or sludge filtering units, acid purification and recovery systems as well as applications for the provision of ultra-pure process water. Our resource recovery and conservation equipment does not only benefit the environment but also our customer’s operational cost structure.


Degreasing & surface cleaning operations are a precondition in most chemical pretreatment sequences. Removal of oils from the used process solution increases the lifespan of treatment baths considerably (saving on costs for disposal and fresh makeup) and can also improve process quality. EST oil separators use a proven and straightforward two-chamber physical separation principle to remove suspended oil from a liquid stream.

Technical Details

  • continuous contaminant removal by flow-through-principle light liquid separator

  • two step separation procedure: coarse separation stage followed by fine separation coalescence cassettes

  • with thermal insulation for hot media feeds

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Frequent disposal of spent pickling acid constitutes one of the main operational cost factors in material surface pretreatment processes. Additionally, slowly rising concentrations of dissolved metals from the pickling reaction inside the pickling tanks does gradually lead to a decline in pickling performance and may also cause excessive sludge formation. The EST acid purification unit (APU) makes these concerns a thing of the past through continuous removal of iron salts from the pickling solution by a simple yet highly efficient, resin-bed-driven physical separation method. APU technology allows a customer to keep pickling tank chemical composition constant throughout continued operation, making required pickling times predictable while averting the risk of sludge formation as well as diminishing disposal costs.

Technical Details

  • continuous removal of dissolved metals from pickling acids by "acid retardation" effect

  • no periodic dumping of spent pickling acid

  • applicable for all common pickling acid systems (hydrochloric, sulfuric, nitric / hydrofluoric, etc.) as well as other chemical systems (e.g. removal of metal salts from alkaline agents)

  • high free acid reclamation rate (up to 95 %) by advanced process sequence

  • available with integrated heat recovery for hot pickling procedures



For some chemical pretreatment processes, be it fluxing, zinc phosphating or others, the formation of fine precipitates and / or sludge is unavoidable due to the nature of the chemical treatment procedure. Here, EST Process Tank Desludging technology may help our customers to improve overall process quality and cleanliness as well as to avoid regular tedious decanting and sludge removal operations for the process tanks. Depending on the type of process and the characteristics of the precipitates and sludge we may offer a number of solutions adequate to our customer's needs.

Technical Details

  • efficient removal of suspended solids by continuous circulation of the media through the filtering system

  • direct solid removal by filter press or with prior sludge accumulation by lamella clarifier

  • available with in-line chemical treatment system (e.g. for chemical oxidation in iron removal from fluxing solution)

  • automated desludging process control